From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 23 Jan 2022 22:58:11 -0800
Subject: [PATCH] ConcurrentUtil
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/collection/MultiThreadedQueue.java b/src/main/java/ca/spottedleaf/concurrentutil/collection/MultiThreadedQueue.java
new file mode 100644
index 0000000000000000000000000000000000000000..f84a622dc29750139ac280f480b7cd132b036287
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/collection/MultiThreadedQueue.java
@@ -0,0 +1,1421 @@
+package ca.spottedleaf.concurrentutil.collection;
+
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import ca.spottedleaf.concurrentutil.util.Validate;
+
+import java.lang.invoke.VarHandle;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Queue;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.function.Consumer;
+import java.util.function.IntFunction;
+import java.util.function.Predicate;
+
+/**
+ * MT-Safe linked first in first out ordered queue.
+ *
+ * This queue should out-perform {@link java.util.concurrent.ConcurrentLinkedQueue} in high-contention reads/writes, and is
+ * not any slower in lower contention reads/writes.
+ * <p>
+ * Note that this queue breaks the specification laid out by {@link Collection}, see {@link #preventAdds()} and {@link Collection#add(Object)}.
+ * </p>
+ * <p><b>
+ * This queue will only unlink linked nodes through the {@link #peek()} and {@link #poll()} methods, and this is only if
+ * they are at the head of the queue.
+ * </b></p>
+ * @param <E> Type of element in this queue.
+ */
+public class MultiThreadedQueue<E> implements Queue<E> {
+
+ protected volatile LinkedNode<E> head; /* Always non-null, high chance of being the actual head */
+
+ protected volatile LinkedNode<E> tail; /* Always non-null, high chance of being the actual tail */
+
+ /* Note that it is possible to reach head from tail. */
+
+ /* IMPL NOTE: Leave hashCode and equals to their defaults */
+
+ protected static final VarHandle HEAD_HANDLE = ConcurrentUtil.getVarHandle(MultiThreadedQueue.class, "head", LinkedNode.class);
+ protected static final VarHandle TAIL_HANDLE = ConcurrentUtil.getVarHandle(MultiThreadedQueue.class, "tail", LinkedNode.class);
+
+ /* head */
+
+ protected final void setHeadPlain(final LinkedNode<E> newHead) {
+ HEAD_HANDLE.set(this, newHead);
+ }
+
+ protected final void setHeadOpaque(final LinkedNode<E> newHead) {
+ HEAD_HANDLE.setOpaque(this, newHead);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getHeadPlain() {
+ return (LinkedNode<E>)HEAD_HANDLE.get(this);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getHeadOpaque() {
+ return (LinkedNode<E>)HEAD_HANDLE.getOpaque(this);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getHeadAcquire() {
+ return (LinkedNode<E>)HEAD_HANDLE.getAcquire(this);
+ }
+
+ /* tail */
+
+ protected final void setTailPlain(final LinkedNode<E> newTail) {
+ TAIL_HANDLE.set(this, newTail);
+ }
+
+ protected final void setTailOpaque(final LinkedNode<E> newTail) {
+ TAIL_HANDLE.setOpaque(this, newTail);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getTailPlain() {
+ return (LinkedNode<E>)TAIL_HANDLE.get(this);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getTailOpaque() {
+ return (LinkedNode<E>)TAIL_HANDLE.getOpaque(this);
+ }
+
+ /**
+ * Constructs a {@code MultiThreadedQueue}, initially empty.
+ * <p>
+ * The returned object may not be published without synchronization.
+ * </p>
+ */
+ public MultiThreadedQueue() {
+ final LinkedNode<E> value = new LinkedNode<>(null, null);
+ this.setHeadPlain(value);
+ this.setTailPlain(value);
+ }
+
+ /**
+ * Constructs a {@code MultiThreadedQueue}, initially containing all elements in the specified {@code collection}.
+ * <p>
+ * The returned object may not be published without synchronization.
+ * </p>
+ * @param collection The specified collection.
+ * @throws NullPointerException If {@code collection} is {@code null} or contains {@code null} elements.
+ */
+ public MultiThreadedQueue(final Iterable<? extends E> collection) {
+ final Iterator<? extends E> elements = collection.iterator();
+
+ if (!elements.hasNext()) {
+ final LinkedNode<E> value = new LinkedNode<>(null, null);
+ this.setHeadPlain(value);
+ this.setTailPlain(value);
+ return;
+ }
+
+ final LinkedNode<E> head = new LinkedNode<>(Validate.notNull(elements.next(), "Null element"), null);
+ LinkedNode<E> tail = head;
+
+ while (elements.hasNext()) {
+ final LinkedNode<E> next = new LinkedNode<>(Validate.notNull(elements.next(), "Null element"), null);
+ tail.setNextPlain(next);
+ tail = next;
+ }
+
+ this.setHeadPlain(head);
+ this.setTailPlain(tail);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public E remove() throws NoSuchElementException {
+ final E ret = this.poll();
+
+ if (ret == null) {
+ throw new NoSuchElementException();
+ }
+
+ return ret;
+ }
+
+ /**
+ * {@inheritDoc}
+ * <p>
+ * Contrary to the specification of {@link Collection#add}, this method will fail to add the element to this queue
+ * and return {@code false} if this queue is add-blocked.
+ * </p>
+ */
+ @Override
+ public boolean add(final E element) {
+ return this.offer(element);
+ }
+
+ /**
+ * Adds the specified element to the tail of this queue. If this queue is currently add-locked, then the queue is
+ * released from that lock and this element is added. The unlock operation and addition of the specified
+ * element is atomic.
+ * @param element The specified element.
+ * @return {@code true} if this queue previously allowed additions
+ */
+ public boolean forceAdd(final E element) {
+ final LinkedNode<E> node = new LinkedNode<>(element, null);
+
+ return !this.forceAppendList(node, node);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public E element() throws NoSuchElementException {
+ final E ret = this.peek();
+
+ if (ret == null) {
+ throw new NoSuchElementException();
+ }
+
+ return ret;
+ }
+
+ /**
+ * {@inheritDoc}
+ * <p>
+ * This method may also return {@code false} to indicate an element was not added if this queue is add-blocked.
+ * </p>
+ */
+ @Override
+ public boolean offer(final E element) {
+ Validate.notNull(element, "Null element");
+
+ final LinkedNode<E> node = new LinkedNode<>(element, null);
+
+ return this.appendList(node, node);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public E peek() {
+ for (LinkedNode<E> head = this.getHeadOpaque(), curr = head;;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ if (this.getHeadOpaque() == head && curr != head) {
+ this.setHeadOpaque(curr);
+ }
+ return element;
+ }
+
+ if (next == null || curr == next) {
+ return null;
+ }
+ curr = next;
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public E poll() {
+ return this.removeHead();
+ }
+
+ /**
+ * Retrieves and removes the head of this queue if it matches the specified predicate. If this queue is empty
+ * or the head does not match the predicate, this function returns {@code null}.
+ * <p>
+ * The predicate may be invoked multiple or no times in this call.
+ * </p>
+ * @param predicate The specified predicate.
+ * @return The head if it matches the predicate, or {@code null} if it did not or this queue is empty.
+ */
+ public E pollIf(final Predicate<E> predicate) {
+ return this.removeHead(Validate.notNull(predicate, "Null predicate"));
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void clear() {
+ //noinspection StatementWithEmptyBody
+ while (this.poll() != null);
+ }
+
+ /**
+ * Prevents elements from being added to this queue. Once this is called, any attempt to add to this queue will fail.
+ * <p>
+ * This function is MT-Safe.
+ * </p>
+ * @return {@code true} if the queue was modified to prevent additions, {@code false} if it already prevented additions.
+ */
+ public boolean preventAdds() {
+ final LinkedNode<E> deadEnd = new LinkedNode<>(null, null);
+ deadEnd.setNextPlain(deadEnd);
+
+ if (!this.appendList(deadEnd, deadEnd)) {
+ return false;
+ }
+
+ this.setTailPlain(deadEnd); /* (try to) Ensure tail is set for the following #allowAdds call */
+ return true;
+ }
+
+ /**
+ * Allows elements to be added to this queue once again. Note that this function has undefined behaviour if
+ * {@link #preventAdds()} is not called beforehand. The benefit of this function over {@link #tryAllowAdds()}
+ * is that this function might perform better.
+ * <p>
+ * This function is not MT-Safe.
+ * </p>
+ */
+ public void allowAdds() {
+ LinkedNode<E> tail = this.getTailPlain();
+
+ /* We need to find the tail given the cas on tail isn't atomic (nor volatile) in this.appendList */
+ /* Thus it is possible for an outdated tail to be set */
+ while (tail != (tail = tail.getNextPlain())) {}
+
+ tail.setNextVolatile(null);
+ }
+
+ /**
+ * Tries to allow elements to be added to this queue. Returns {@code true} if the queue was previous add-locked,
+ * {@code false} otherwise.
+ * <p>
+ * This function is MT-Safe, however it should not be used with {@link #allowAdds()}.
+ * </p>
+ * @return {@code true} if the queue was previously add-locked, {@code false} otherwise.
+ */
+ public boolean tryAllowAdds() {
+ LinkedNode<E> tail = this.getTailPlain();
+
+ for (int failures = 0;;) {
+ /* We need to find the tail given the cas on tail isn't atomic (nor volatile) in this.appendList */
+ /* Thus it is possible for an outdated tail to be set */
+ while (tail != (tail = tail.getNextAcquire())) {
+ if (tail == null) {
+ return false;
+ }
+ }
+
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (tail == (tail = tail.compareExchangeNextVolatile(tail, null))) {
+ return true;
+ }
+
+ if (tail == null) {
+ return false;
+ }
+ ++failures;
+ }
+ }
+
+ /**
+ * Atomically adds the specified element to this queue or allows additions to the queue. If additions
+ * are not allowed, the element is not added.
+ * <p>
+ * This function is MT-Safe.
+ * </p>
+ * @param element The specified element.
+ * @return {@code true} if the queue now allows additions, {@code false} if the element was added.
+ */
+ public boolean addOrAllowAdds(final E element) {
+ Validate.notNull(element, "Null element");
+ int failures = 0;
+
+ final LinkedNode<E> append = new LinkedNode<>(element, null);
+
+ for (LinkedNode<E> currTail = this.getTailOpaque(), curr = currTail;;) {
+ /* It has been experimentally shown that placing the read before the backoff results in significantly greater performance */
+ /* It is likely due to a cache miss caused by another write to the next field */
+ final LinkedNode<E> next = curr.getNextVolatile();
+
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (next == null) {
+ final LinkedNode<E> compared = curr.compareExchangeNextVolatile(null, append);
+
+ if (compared == null) {
+ /* Added */
+ /* Avoid CASing on tail more than we need to */
+ /* CAS to avoid setting an out-of-date tail */
+ if (this.getTailOpaque() == currTail) {
+ this.setTailOpaque(append);
+ }
+ return false; // we added
+ }
+
+ ++failures;
+ curr = compared;
+ continue;
+ } else if (next == curr) {
+ final LinkedNode<E> compared = curr.compareExchangeNextVolatile(curr, null);
+
+ if (compared == curr) {
+ return true; // we let additions through
+ }
+
+ ++failures;
+
+ if (compared != null) {
+ curr = compared;
+ }
+ continue;
+ }
+
+ if (curr == currTail) {
+ /* Tail is likely not up-to-date */
+ curr = next;
+ } else {
+ /* Try to update to tail */
+ if (currTail == (currTail = this.getTailOpaque())) {
+ curr = next;
+ } else {
+ curr = currTail;
+ }
+ }
+ }
+ }
+
+ /**
+ * Returns whether this queue is currently add-blocked. That is, whether {@link #add(Object)} and friends will return {@code false}.
+ */
+ public boolean isAddBlocked() {
+ for (LinkedNode<E> tail = this.getTailOpaque();;) {
+ LinkedNode<E> next = tail.getNextVolatile();
+ if (next == null) {
+ return false;
+ }
+
+ if (next == tail) {
+ return true;
+ }
+
+ tail = next;
+ }
+ }
+
+ /**
+ * Atomically removes the head from this queue if it exists, otherwise prevents additions to this queue if no
+ * head is removed.
+ * <p>
+ * This function is MT-Safe.
+ * </p>
+ * If the queue is already add-blocked and empty then no operation is performed.
+ * @return {@code null} if the queue is now add-blocked or was previously add-blocked, else returns
+ * an non-null value which was the previous head of queue.
+ */
+ public E pollOrBlockAdds() {
+ int failures = 0;
+ for (LinkedNode<E> head = this.getHeadOpaque(), curr = head;;) {
+ final E currentVal = curr.getElementVolatile();
+ final LinkedNode<E> next = curr.getNextOpaque();
+
+ if (next == curr) {
+ return null; /* Additions are already blocked */
+ }
+
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (currentVal != null) {
+ if (curr.getAndSetElementVolatile(null) == null) {
+ ++failures;
+ continue;
+ }
+
+ /* "CAS" to avoid setting an out-of-date head */
+ if (this.getHeadOpaque() == head) {
+ this.setHeadOpaque(next != null ? next : curr);
+ }
+
+ return currentVal;
+ }
+
+ if (next == null) {
+ /* Try to update stale head */
+ if (curr != head && this.getHeadOpaque() == head) {
+ this.setHeadOpaque(curr);
+ }
+
+ final LinkedNode<E> compared = curr.compareExchangeNextVolatile(null, curr);
+
+ if (compared != null) {
+ // failed to block additions
+ curr = compared;
+ ++failures;
+ continue;
+ }
+
+ return null; /* We blocked additions */
+ }
+
+ if (head == curr) {
+ /* head is likely not up-to-date */
+ curr = next;
+ } else {
+ /* Try to update to head */
+ if (head == (head = this.getHeadOpaque())) {
+ curr = next;
+ } else {
+ curr = head;
+ }
+ }
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean remove(final Object object) {
+ Validate.notNull(object, "Null object to remove");
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ if ((element == object || element.equals(object)) && curr.getAndSetElementVolatile(null) == element) {
+ return true;
+ }
+ }
+
+ if (next == curr || next == null) {
+ break;
+ }
+ curr = next;
+ }
+
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean removeIf(final Predicate<? super E> filter) {
+ Validate.notNull(filter, "Null filter");
+
+ boolean ret = false;
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ ret |= filter.test(element) && curr.getAndSetElementVolatile(null) == element;
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return ret;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean removeAll(final Collection<?> collection) {
+ Validate.notNull(collection, "Null collection");
+
+ boolean ret = false;
+
+ /* Volatile is required to synchronize with the write to the first element */
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ ret |= collection.contains(element) && curr.getAndSetElementVolatile(null) == element;
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return ret;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean retainAll(final Collection<?> collection) {
+ Validate.notNull(collection, "Null collection");
+
+ boolean ret = false;
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ ret |= !collection.contains(element) && curr.getAndSetElementVolatile(null) == element;
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return ret;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public Object[] toArray() {
+ final List<E> ret = new ArrayList<>();
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ ret.add(element);
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return ret.toArray();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public <T> T[] toArray(final T[] array) {
+ final List<T> ret = new ArrayList<>();
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ //noinspection unchecked
+ ret.add((T)element);
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return ret.toArray(array);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public <T> T[] toArray(final IntFunction<T[]> generator) {
+ Validate.notNull(generator, "Null generator");
+
+ final List<T> ret = new ArrayList<>();
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ //noinspection unchecked
+ ret.add((T)element);
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return ret.toArray(generator);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public String toString() {
+ final StringBuilder builder = new StringBuilder();
+
+ builder.append("MultiThreadedQueue: {elements: {");
+
+ int deadEntries = 0;
+ int totalEntries = 0;
+ int aliveEntries = 0;
+
+ boolean addLocked = false;
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();; ++totalEntries) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element == null) {
+ ++deadEntries;
+ } else {
+ ++aliveEntries;
+ }
+
+ if (totalEntries != 0) {
+ builder.append(", ");
+ }
+
+ builder.append(totalEntries).append(": \"").append(element).append('"');
+
+ if (next == null) {
+ break;
+ }
+ if (curr == next) {
+ addLocked = true;
+ break;
+ }
+ curr = next;
+ }
+
+ builder.append("}, total_entries: \"").append(totalEntries).append("\", alive_entries: \"").append(aliveEntries)
+ .append("\", dead_entries:").append(deadEntries).append("\", add_locked: \"").append(addLocked)
+ .append("\"}");
+
+ return builder.toString();
+ }
+
+ /**
+ * Adds all elements from the specified collection to this queue. The addition is atomic.
+ * @param collection The specified collection.
+ * @return {@code true} if all elements were added successfully, or {@code false} if this queue is add-blocked, or
+ * {@code false} if the specified collection contains no elements.
+ */
+ @Override
+ public boolean addAll(final Collection<? extends E> collection) {
+ return this.addAll((Iterable<? extends E>)collection);
+ }
+
+ /**
+ * Adds all elements from the specified iterable object to this queue. The addition is atomic.
+ * @param iterable The specified iterable object.
+ * @return {@code true} if all elements were added successfully, or {@code false} if this queue is add-blocked, or
+ * {@code false} if the specified iterable contains no elements.
+ */
+ public boolean addAll(final Iterable<? extends E> iterable) {
+ Validate.notNull(iterable, "Null iterable");
+
+ final Iterator<? extends E> elements = iterable.iterator();
+ if (!elements.hasNext()) {
+ return false;
+ }
+
+ /* Build a list of nodes to append */
+ /* This is an much faster due to the fact that zero additional synchronization is performed */
+
+ final LinkedNode<E> head = new LinkedNode<>(Validate.notNull(elements.next(), "Null element"), null);
+ LinkedNode<E> tail = head;
+
+ while (elements.hasNext()) {
+ final LinkedNode<E> next = new LinkedNode<>(Validate.notNull(elements.next(), "Null element"), null);
+ tail.setNextPlain(next);
+ tail = next;
+ }
+
+ return this.appendList(head, tail);
+ }
+
+ /**
+ * Adds all of the elements from the specified array to this queue.
+ * @param items The specified array.
+ * @return {@code true} if all elements were added successfully, or {@code false} if this queue is add-blocked, or
+ * {@code false} if the specified array has a length of 0.
+ */
+ public boolean addAll(final E[] items) {
+ return this.addAll(items, 0, items.length);
+ }
+
+ /**
+ * Adds all of the elements from the specified array to this queue.
+ * @param items The specified array.
+ * @param off The offset in the array.
+ * @param len The number of items.
+ * @return {@code true} if all elements were added successfully, or {@code false} if this queue is add-blocked, or
+ * {@code false} if the specified array has a length of 0.
+ */
+ public boolean addAll(final E[] items, final int off, final int len) {
+ Validate.notNull(items, "Items may not be null");
+ Validate.arrayBounds(off, len, items.length, "Items array indices out of bounds");
+
+ if (len == 0) {
+ return false;
+ }
+
+ final LinkedNode<E> head = new LinkedNode<>(Validate.notNull(items[off], "Null element"), null);
+ LinkedNode<E> tail = head;
+
+ for (int i = 1; i < len; ++i) {
+ final LinkedNode<E> next = new LinkedNode<>(Validate.notNull(items[off + i], "Null element"), null);
+ tail.setNextPlain(next);
+ tail = next;
+ }
+
+ return this.appendList(head, tail);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean containsAll(final Collection<?> collection) {
+ Validate.notNull(collection, "Null collection");
+
+ for (final Object element : collection) {
+ if (!this.contains(element)) {
+ return false;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public Iterator<E> iterator() {
+ return new LinkedIterator<>(this.getHeadOpaque());
+ }
+
+ /**
+ * {@inheritDoc}
+ * <p>
+ * Note that this function is computed non-atomically and in O(n) time. The value returned may not be representative of
+ * the queue in its current state.
+ * </p>
+ */
+ @Override
+ public int size() {
+ int size = 0;
+
+ /* Volatile is required to synchronize with the write to the first element */
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ ++size;
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return size;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean isEmpty() {
+ return this.peek() == null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean contains(final Object object) {
+ Validate.notNull(object, "Null object");
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null && (element == object || element.equals(object))) {
+ return true;
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return false;
+ }
+
+ /**
+ * Finds the first element in this queue that matches the predicate.
+ * @param predicate The predicate to test elements against.
+ * @return The first element that matched the predicate, {@code null} if none matched.
+ */
+ public E find(final Predicate<E> predicate) {
+ Validate.notNull(predicate, "Null predicate");
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null && predicate.test(element)) {
+ return element;
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+
+ return null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void forEach(final Consumer<? super E> action) {
+ Validate.notNull(action, "Null action");
+
+ for (LinkedNode<E> curr = this.getHeadOpaque();;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E element = curr.getElementPlain(); /* Likely in sync */
+
+ if (element != null) {
+ action.accept(element);
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+ }
+
+ // return true if normal addition, false if the queue previously disallowed additions
+ protected final boolean forceAppendList(final LinkedNode<E> head, final LinkedNode<E> tail) {
+ int failures = 0;
+
+ for (LinkedNode<E> currTail = this.getTailOpaque(), curr = currTail;;) {
+ /* It has been experimentally shown that placing the read before the backoff results in significantly greater performance */
+ /* It is likely due to a cache miss caused by another write to the next field */
+ final LinkedNode<E> next = curr.getNextVolatile();
+
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (next == null || next == curr) {
+ final LinkedNode<E> compared = curr.compareExchangeNextVolatile(next, head);
+
+ if (compared == next) {
+ /* Added */
+ /* Avoid CASing on tail more than we need to */
+ /* "CAS" to avoid setting an out-of-date tail */
+ if (this.getTailOpaque() == currTail) {
+ this.setTailOpaque(tail);
+ }
+ return next != curr;
+ }
+
+ ++failures;
+ curr = compared;
+ continue;
+ }
+
+ if (curr == currTail) {
+ /* Tail is likely not up-to-date */
+ curr = next;
+ } else {
+ /* Try to update to tail */
+ if (currTail == (currTail = this.getTailOpaque())) {
+ curr = next;
+ } else {
+ curr = currTail;
+ }
+ }
+ }
+ }
+
+ // return true if successful, false otherwise
+ protected final boolean appendList(final LinkedNode<E> head, final LinkedNode<E> tail) {
+ int failures = 0;
+
+ for (LinkedNode<E> currTail = this.getTailOpaque(), curr = currTail;;) {
+ /* It has been experimentally shown that placing the read before the backoff results in significantly greater performance */
+ /* It is likely due to a cache miss caused by another write to the next field */
+ final LinkedNode<E> next = curr.getNextVolatile();
+
+ if (next == curr) {
+ /* Additions are stopped */
+ return false;
+ }
+
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (next == null) {
+ final LinkedNode<E> compared = curr.compareExchangeNextVolatile(null, head);
+
+ if (compared == null) {
+ /* Added */
+ /* Avoid CASing on tail more than we need to */
+ /* CAS to avoid setting an out-of-date tail */
+ if (this.getTailOpaque() == currTail) {
+ this.setTailOpaque(tail);
+ }
+ return true;
+ }
+
+ ++failures;
+ curr = compared;
+ continue;
+ }
+
+ if (curr == currTail) {
+ /* Tail is likely not up-to-date */
+ curr = next;
+ } else {
+ /* Try to update to tail */
+ if (currTail == (currTail = this.getTailOpaque())) {
+ curr = next;
+ } else {
+ curr = currTail;
+ }
+ }
+ }
+ }
+
+ protected final E removeHead(final Predicate<E> predicate) {
+ int failures = 0;
+ for (LinkedNode<E> head = this.getHeadOpaque(), curr = head;;) {
+ // volatile here synchronizes-with writes to element
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E currentVal = curr.getElementPlain();
+
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (currentVal != null) {
+ if (!predicate.test(currentVal)) {
+ /* Try to update stale head */
+ if (curr != head && this.getHeadOpaque() == head) {
+ this.setHeadOpaque(curr);
+ }
+ return null;
+ }
+ if (curr.getAndSetElementVolatile(null) == null) {
+ /* Failed to get head */
+ if (curr == (curr = next) || next == null) {
+ return null;
+ }
+ ++failures;
+ continue;
+ }
+
+ /* "CAS" to avoid setting an out-of-date head */
+ if (this.getHeadOpaque() == head) {
+ this.setHeadOpaque(next != null ? next : curr);
+ }
+
+ return currentVal;
+ }
+
+ if (curr == next || next == null) {
+ /* Try to update stale head */
+ if (curr != head && this.getHeadOpaque() == head) {
+ this.setHeadOpaque(curr);
+ }
+ return null; /* End of queue */
+ }
+
+ if (head == curr) {
+ /* head is likely not up-to-date */
+ curr = next;
+ } else {
+ /* Try to update to head */
+ if (head == (head = this.getHeadOpaque())) {
+ curr = next;
+ } else {
+ curr = head;
+ }
+ }
+ }
+ }
+
+ protected final E removeHead() {
+ int failures = 0;
+ for (LinkedNode<E> head = this.getHeadOpaque(), curr = head;;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+ final E currentVal = curr.getElementPlain();
+
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (currentVal != null) {
+ if (curr.getAndSetElementVolatile(null) == null) {
+ /* Failed to get head */
+ if (curr == (curr = next) || next == null) {
+ return null;
+ }
+ ++failures;
+ continue;
+ }
+
+ /* "CAS" to avoid setting an out-of-date head */
+ if (this.getHeadOpaque() == head) {
+ this.setHeadOpaque(next != null ? next : curr);
+ }
+
+ return currentVal;
+ }
+
+ if (curr == next || next == null) {
+ /* Try to update stale head */
+ if (curr != head && this.getHeadOpaque() == head) {
+ this.setHeadOpaque(curr);
+ }
+ return null; /* End of queue */
+ }
+
+ if (head == curr) {
+ /* head is likely not up-to-date */
+ curr = next;
+ } else {
+ /* Try to update to head */
+ if (head == (head = this.getHeadOpaque())) {
+ curr = next;
+ } else {
+ curr = head;
+ }
+ }
+ }
+ }
+
+ /**
+ * Empties the queue into the specified consumer. This function is optimized for single-threaded reads, and should
+ * be faster than a loop on {@link #poll()}.
+ * <p>
+ * This function is not MT-Safe. This function cannot be called with other read operations ({@link #peek()}, {@link #poll()},
+ * {@link #clear()}, etc).
+ * Write operations are safe to be called concurrently.
+ * </p>
+ * @param consumer The consumer to accept the elements.
+ * @return The total number of elements drained.
+ */
+ public int drain(final Consumer<E> consumer) {
+ return this.drain(consumer, false, ConcurrentUtil::rethrow);
+ }
+
+ /**
+ * Empties the queue into the specified consumer. This function is optimized for single-threaded reads, and should
+ * be faster than a loop on {@link #poll()}.
+ * <p>
+ * If {@code preventAdds} is {@code true}, then after this function returns the queue is guaranteed to be empty and
+ * additions to the queue will fail.
+ * </p>
+ * <p>
+ * This function is not MT-Safe. This function cannot be called with other read operations ({@link #peek()}, {@link #poll()},
+ * {@link #clear()}, etc).
+ * Write operations are safe to be called concurrently.
+ * </p>
+ * @param consumer The consumer to accept the elements.
+ * @param preventAdds Whether to prevent additions to this queue after draining.
+ * @return The total number of elements drained.
+ */
+ public int drain(final Consumer<E> consumer, final boolean preventAdds) {
+ return this.drain(consumer, preventAdds, ConcurrentUtil::rethrow);
+ }
+
+ /**
+ * Empties the queue into the specified consumer. This function is optimized for single-threaded reads, and should
+ * be faster than a loop on {@link #poll()}.
+ * <p>
+ * If {@code preventAdds} is {@code true}, then after this function returns the queue is guaranteed to be empty and
+ * additions to the queue will fail.
+ * </p>
+ * <p>
+ * This function is not MT-Safe. This function cannot be called with other read operations ({@link #peek()}, {@link #poll()},
+ * {@link #clear()}, {@link #remove(Object)} etc).
+ * Only write operations are safe to be called concurrently.
+ * </p>
+ * @param consumer The consumer to accept the elements.
+ * @param preventAdds Whether to prevent additions to this queue after draining.
+ * @param exceptionHandler Invoked when the consumer raises an exception.
+ * @return The total number of elements drained.
+ */
+ public int drain(final Consumer<E> consumer, final boolean preventAdds, final Consumer<Throwable> exceptionHandler) {
+ Validate.notNull(consumer, "Null consumer");
+ Validate.notNull(exceptionHandler, "Null exception handler");
+
+ /* This function assumes proper synchronization is made to ensure drain and no other read function are called concurrently */
+ /* This allows plain write usages instead of opaque or higher */
+ int total = 0;
+
+ final LinkedNode<E> head = this.getHeadAcquire(); /* Required to synchronize with the write to the first element field */
+ LinkedNode<E> curr = head;
+
+ for (;;) {
+ /* Volatile acquires with the write to the element field */
+ final E currentVal = curr.getElementPlain();
+ LinkedNode<E> next = curr.getNextVolatile();
+
+ if (next == curr) {
+ /* Add-locked nodes always have a null value */
+ break;
+ }
+
+ if (currentVal == null) {
+ if (next == null) {
+ if (preventAdds && (next = curr.compareExchangeNextVolatile(null, curr)) != null) {
+ // failed to prevent adds, continue
+ curr = next;
+ continue;
+ } else {
+ // we're done here
+ break;
+ }
+ }
+ curr = next;
+ continue;
+ }
+
+ try {
+ consumer.accept(currentVal);
+ } catch (final Exception ex) {
+ this.setHeadOpaque(next != null ? next : curr); /* Avoid perf penalty (of reiterating) if the exception handler decides to re-throw */
+ curr.setElementOpaque(null); /* set here, we might re-throw */
+
+ exceptionHandler.accept(ex);
+ }
+
+ curr.setElementOpaque(null);
+
+ ++total;
+
+ if (next == null) {
+ if (preventAdds && (next = curr.compareExchangeNextVolatile(null, curr)) != null) {
+ /* Retry with next value */
+ curr = next;
+ continue;
+ }
+ break;
+ }
+
+ curr = next;
+ }
+ if (curr != head) {
+ this.setHeadOpaque(curr); /* While this may be a plain write, eventually publish it for methods such as find. */
+ }
+ return total;
+ }
+
+ @Override
+ public Spliterator<E> spliterator() { // TODO implement
+ return Spliterators.spliterator(this, Spliterator.CONCURRENT |
+ Spliterator.NONNULL | Spliterator.ORDERED);
+ }
+
+ protected static final class LinkedNode<E> {
+
+ protected volatile Object element;
+ protected volatile LinkedNode<E> next;
+
+ protected static final VarHandle ELEMENT_HANDLE = ConcurrentUtil.getVarHandle(LinkedNode.class, "element", Object.class);
+ protected static final VarHandle NEXT_HANDLE = ConcurrentUtil.getVarHandle(LinkedNode.class, "next", LinkedNode.class);
+
+ protected LinkedNode(final Object element, final LinkedNode<E> next) {
+ ELEMENT_HANDLE.set(this, element);
+ NEXT_HANDLE.set(this, next);
+ }
+
+ /* element */
+
+ @SuppressWarnings("unchecked")
+ protected final E getElementPlain() {
+ return (E)ELEMENT_HANDLE.get(this);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final E getElementVolatile() {
+ return (E)ELEMENT_HANDLE.getVolatile(this);
+ }
+
+ protected final void setElementPlain(final E update) {
+ ELEMENT_HANDLE.set(this, (Object)update);
+ }
+
+ protected final void setElementOpaque(final E update) {
+ ELEMENT_HANDLE.setOpaque(this, (Object)update);
+ }
+
+ protected final void setElementVolatile(final E update) {
+ ELEMENT_HANDLE.setVolatile(this, (Object)update);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final E getAndSetElementVolatile(final E update) {
+ return (E)ELEMENT_HANDLE.getAndSet(this, update);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final E compareExchangeElementVolatile(final E expect, final E update) {
+ return (E)ELEMENT_HANDLE.compareAndExchange(this, expect, update);
+ }
+
+ /* next */
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getNextPlain() {
+ return (LinkedNode<E>)NEXT_HANDLE.get(this);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getNextOpaque() {
+ return (LinkedNode<E>)NEXT_HANDLE.getOpaque(this);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getNextAcquire() {
+ return (LinkedNode<E>)NEXT_HANDLE.getAcquire(this);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getNextVolatile() {
+ return (LinkedNode<E>)NEXT_HANDLE.getVolatile(this);
+ }
+
+ protected final void setNextPlain(final LinkedNode<E> next) {
+ NEXT_HANDLE.set(this, next);
+ }
+
+ protected final void setNextVolatile(final LinkedNode<E> next) {
+ NEXT_HANDLE.setVolatile(this, next);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> compareExchangeNextVolatile(final LinkedNode<E> expect, final LinkedNode<E> set) {
+ return (LinkedNode<E>)NEXT_HANDLE.compareAndExchange(this, expect, set);
+ }
+ }
+
+ protected static final class LinkedIterator<E> implements Iterator<E> {
+
+ protected LinkedNode<E> curr; /* last returned by next() */
+ protected LinkedNode<E> next; /* next to return from next() */
+ protected E nextElement; /* cached to avoid a race condition with removing or polling */
+
+ protected LinkedIterator(final LinkedNode<E> start) {
+ /* setup nextElement and next */
+ for (LinkedNode<E> curr = start;;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+
+ final E element = curr.getElementPlain();
+
+ if (element != null) {
+ this.nextElement = element;
+ this.next = curr;
+ break;
+ }
+
+ if (next == null || next == curr) {
+ break;
+ }
+ curr = next;
+ }
+ }
+
+ protected final void findNext() {
+ /* only called if this.nextElement != null, which means this.next != null */
+ for (LinkedNode<E> curr = this.next;;) {
+ final LinkedNode<E> next = curr.getNextVolatile();
+
+ if (next == null || next == curr) {
+ break;
+ }
+
+ final E element = next.getElementPlain();
+
+ if (element != null) {
+ this.nextElement = element;
+ this.curr = this.next; /* this.next will be the value returned from next(), set this.curr for remove() */
+ this.next = next;
+ return;
+ }
+ curr = next;
+ }
+
+ /* out of nodes to iterate */
+ /* keep curr for remove() calls */
+ this.next = null;
+ this.nextElement = null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean hasNext() {
+ return this.nextElement != null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public E next() {
+ final E element = this.nextElement;
+
+ if (element == null) {
+ throw new NoSuchElementException();
+ }
+
+ this.findNext();
+
+ return element;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void remove() {
+ if (this.curr == null) {
+ throw new IllegalStateException();
+ }
+
+ this.curr.setElementVolatile(null);
+ this.curr = null;
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/collection/SRSWLinkedQueue.java b/src/main/java/ca/spottedleaf/concurrentutil/collection/SRSWLinkedQueue.java
new file mode 100644
index 0000000000000000000000000000000000000000..094eff418b4e3bffce020d650931b4d9e58fa9ed
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/collection/SRSWLinkedQueue.java
@@ -0,0 +1,149 @@
+package ca.spottedleaf.concurrentutil.collection;
+
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import ca.spottedleaf.concurrentutil.util.Validate;
+
+import java.lang.invoke.VarHandle;
+import java.util.ConcurrentModificationException;
+
+/**
+ * Single reader thread single writer thread queue. The reader side of the queue is ordered by acquire semantics,
+ * and the writer side of the queue is ordered by release semantics.
+ */
+// TODO test
+public class SRSWLinkedQueue<E> {
+
+ // always non-null
+ protected LinkedNode<E> head;
+
+ // always non-null
+ protected LinkedNode<E> tail;
+
+ /* IMPL NOTE: Leave hashCode and equals to their defaults */
+
+ public SRSWLinkedQueue() {
+ final LinkedNode<E> dummy = new LinkedNode<>(null, null);
+ this.head = this.tail = dummy;
+ }
+
+ /**
+ * Must be the reader thread.
+ *
+ * <p>
+ * Returns, without removing, the first element of this queue.
+ * </p>
+ * @return Returns, without removing, the first element of this queue.
+ */
+ public E peekFirst() {
+ LinkedNode<E> head = this.head;
+ E ret = head.getElementPlain();
+ if (ret == null) {
+ head = head.getNextAcquire();
+ if (head == null) {
+ // empty
+ return null;
+ }
+ // update head reference for next poll() call
+ this.head = head;
+ // guaranteed to be non-null
+ ret = head.getElementPlain();
+ if (ret == null) {
+ throw new ConcurrentModificationException("Multiple reader threads");
+ }
+ }
+
+ return ret;
+ }
+
+ /**
+ * Must be the reader thread.
+ *
+ * <p>
+ * Returns and removes the first element of this queue.
+ * </p>
+ * @return Returns and removes the first element of this queue.
+ */
+ public E poll() {
+ LinkedNode<E> head = this.head;
+ E ret = head.getElementPlain();
+ if (ret == null) {
+ head = head.getNextAcquire();
+ if (head == null) {
+ // empty
+ return null;
+ }
+ // guaranteed to be non-null
+ ret = head.getElementPlain();
+ if (ret == null) {
+ throw new ConcurrentModificationException("Multiple reader threads");
+ }
+ }
+
+ head.setElementPlain(null);
+ LinkedNode<E> next = head.getNextAcquire();
+ this.head = next == null ? head : next;
+
+ return ret;
+ }
+
+ /**
+ * Must be the writer thread.
+ *
+ * <p>
+ * Adds the element to the end of the queue.
+ * </p>
+ *
+ * @throws NullPointerException If the provided element is null
+ */
+ public void addLast(final E element) {
+ Validate.notNull(element, "Provided element cannot be null");
+ final LinkedNode<E> append = new LinkedNode<>(element, null);
+
+ this.tail.setNextRelease(append);
+ this.tail = append;
+ }
+
+ protected static final class LinkedNode<E> {
+
+ protected volatile Object element;
+ protected volatile LinkedNode<E> next;
+
+ protected static final VarHandle ELEMENT_HANDLE = ConcurrentUtil.getVarHandle(LinkedNode.class, "element", Object.class);
+ protected static final VarHandle NEXT_HANDLE = ConcurrentUtil.getVarHandle(LinkedNode.class, "next", LinkedNode.class);
+
+ protected LinkedNode(final Object element, final LinkedNode<E> next) {
+ ELEMENT_HANDLE.set(this, element);
+ NEXT_HANDLE.set(this, next);
+ }
+
+ /* element */
+
+ @SuppressWarnings("unchecked")
+ protected final E getElementPlain() {
+ return (E)ELEMENT_HANDLE.get(this);
+ }
+
+ protected final void setElementPlain(final E update) {
+ ELEMENT_HANDLE.set(this, (Object)update);
+ }
+ /* next */
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getNextPlain() {
+ return (LinkedNode<E>)NEXT_HANDLE.get(this);
+ }
+
+ @SuppressWarnings("unchecked")
+ protected final LinkedNode<E> getNextAcquire() {
+ return (LinkedNode<E>)NEXT_HANDLE.getAcquire(this);
+ }
+
+ protected final void setNextPlain(final LinkedNode<E> next) {
+ NEXT_HANDLE.set(this, next);
+ }
+
+ protected final void setNextRelease(final LinkedNode<E> next) {
+ NEXT_HANDLE.setRelease(this, next);
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/completable/Completable.java b/src/main/java/ca/spottedleaf/concurrentutil/completable/Completable.java
new file mode 100644
index 0000000000000000000000000000000000000000..46d1bd01542ebeeffc0006a5c585a50dbbbff907
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/completable/Completable.java
@@ -0,0 +1,112 @@
+package ca.spottedleaf.concurrentutil.completable;
+
+import ca.spottedleaf.concurrentutil.collection.MultiThreadedQueue;
+import ca.spottedleaf.concurrentutil.executor.Cancellable;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.util.function.BiConsumer;
+
+public final class Completable<T> {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(Completable.class);
+
+ private final MultiThreadedQueue<BiConsumer<T, Throwable>> waiters = new MultiThreadedQueue<>();
+ private T result;
+ private Throwable throwable;
+ private volatile boolean completed;
+
+ public boolean isCompleted() {
+ return this.completed;
+ }
+
+ /**
+ * Note: Can only use after calling {@link #addAsynchronousWaiter(BiConsumer)}, as this function performs zero
+ * synchronisation
+ */
+ public T getResult() {
+ return this.result;
+ }
+
+ /**
+ * Note: Can only use after calling {@link #addAsynchronousWaiter(BiConsumer)}, as this function performs zero
+ * synchronisation
+ */
+ public Throwable getThrowable() {
+ return this.throwable;
+ }
+
+ /**
+ * Adds a waiter that should only be completed asynchronously by the complete() calls. If complete()
+ * has already been called, returns {@code null} and does not invoke the specified consumer.
+ * @param consumer Consumer to be executed on completion
+ * @throws NullPointerException If consumer is null
+ * @return A cancellable which will control the execution of the specified consumer
+ */
+ public Cancellable addAsynchronousWaiter(final BiConsumer<T, Throwable> consumer) {
+ if (this.waiters.add(consumer)) {
+ return new CancellableImpl(consumer);
+ }
+ return null;
+ }
+
+ private void completeAllWaiters(final T result, final Throwable throwable) {
+ this.completed = true;
+ BiConsumer<T, Throwable> waiter;
+ while ((waiter = this.waiters.pollOrBlockAdds()) != null) {
+ this.completeWaiter(waiter, result, throwable);
+ }
+ }
+
+ private void completeWaiter(final BiConsumer<T, Throwable> consumer, final T result, final Throwable throwable) {
+ try {
+ consumer.accept(result, throwable);
+ } catch (final ThreadDeath death) {
+ throw death;
+ } catch (final Throwable throwable2) {
+ LOGGER.error("Failed to complete callback " + ConcurrentUtil.genericToString(consumer), throwable2);
+ }
+ }
+
+ /**
+ * Adds a waiter that will be completed asynchronously by the complete() calls. If complete()
+ * has already been called, then invokes the consumer synchronously with the completed result.
+ * @param consumer Consumer to be executed on completion
+ * @throws NullPointerException If consumer is null
+ * @return A cancellable which will control the execution of the specified consumer
+ */
+ public Cancellable addWaiter(final BiConsumer<T, Throwable> consumer) {
+ if (this.waiters.add(consumer)) {
+ return new CancellableImpl(consumer);
+ }
+ this.completeWaiter(consumer, this.result, this.throwable);
+ return new CancellableImpl(consumer);
+ }
+
+ public void complete(final T result) {
+ this.result = result;
+ this.completeAllWaiters(result, null);
+ }
+
+ public void completeWithThrowable(final Throwable throwable) {
+ if (throwable == null) {
+ throw new NullPointerException("Throwable cannot be null");
+ }
+ this.throwable = throwable;
+ this.completeAllWaiters(null, throwable);
+ }
+
+ private final class CancellableImpl implements Cancellable {
+
+ private final BiConsumer<T, Throwable> waiter;
+
+ private CancellableImpl(final BiConsumer<T, Throwable> waiter) {
+ this.waiter = waiter;
+ }
+
+ @Override
+ public boolean cancel() {
+ return Completable.this.waiters.remove(this.waiter);
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/executor/BaseExecutor.java b/src/main/java/ca/spottedleaf/concurrentutil/executor/BaseExecutor.java
new file mode 100644
index 0000000000000000000000000000000000000000..18d646676fd022afd64afaac30ec1bd283a73b0e
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/BaseExecutor.java
@@ -0,0 +1,208 @@
+package ca.spottedleaf.concurrentutil.executor;
+
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import java.util.function.BooleanSupplier;
+
+/**
+ * Base implementation for an abstract queue of tasks which are executed either synchronously or asynchronously.
+ *
+ * <p>
+ * The implementation supports tracking task executions using {@link #getTotalTasksScheduled()} and
+ * {@link #getTotalTasksExecuted()}, and optionally shutting down the executor using {@link #shutdown()}
+ * </p>
+ *
+ * <p>
+ * The base implementation does not provide a method to queue a task for execution, rather that is specified in
+ * the specific implementation. However, it is required that a specific implementation provides a method to
+ * <i>queue</i> a task or <i>create</i> a task. A <i>queued</i> task is one which will eventually be executed,
+ * and a <i>created</i> task must be queued to execute via {@link BaseTask#queue()} or be executed manually via
+ * {@link BaseTask#execute()}. This choice of delaying the queueing of a task may be useful to provide a task handle
+ * which may be cancelled or adjusted before the actual real task logic is ready to be executed.
+ * </p>
+ */
+public interface BaseExecutor {
+
+ /**
+ * Returns whether every task scheduled to this queue has been removed and executed or cancelled. If no tasks have been queued,
+ * returns {@code true}.
+ *
+ * @return {@code true} if all tasks that have been queued have finished executing or no tasks have been queued, {@code false} otherwise.
+ */
+ public default boolean haveAllTasksExecuted() {
+ // order is important
+ // if new tasks are scheduled between the reading of these variables, scheduled is guaranteed to be higher -
+ // so our check fails, and we try again
+ final long completed = this.getTotalTasksExecuted();
+ final long scheduled = this.getTotalTasksScheduled();
+
+ return completed == scheduled;
+ }
+
+ /**
+ * Returns the number of tasks that have been scheduled or execute or are pending to be scheduled.
+ */
+ public long getTotalTasksScheduled();
+
+ /**
+ * Returns the number of tasks that have fully been executed.
+ */
+ public long getTotalTasksExecuted();
+
+ /**
+ * Waits until this queue has had all of its tasks executed (NOT removed). See {@link #haveAllTasksExecuted()}
+ * <p>
+ * This call is most effective after a {@link #shutdown()} call, as the shutdown call guarantees no tasks can
+ * be executed and the waitUntilAllExecuted call makes sure the queue is empty. Effectively, using shutdown then using
+ * waitUntilAllExecuted ensures this queue is empty - and most importantly, will remain empty.
+ * </p>
+ * <p>
+ * This method is not guaranteed to be immediately responsive to queue state, so calls may take significantly more
+ * time than expected. Effectively, do not rely on this call being fast - even if there are few tasks scheduled.
+ * </p>
+ * <p>
+ * Note: Interruptions to the the current thread have no effect. Interrupt status is also not affected by this call.
+ * </p>
+ *
+ * @throws IllegalStateException If the current thread is not allowed to wait
+ */
+ public default void waitUntilAllExecuted() throws IllegalStateException {
+ long failures = 1L; // start at 0.25ms
+
+ while (!this.haveAllTasksExecuted()) {
+ Thread.yield();
+ failures = ConcurrentUtil.linearLongBackoff(failures, 250_000L, 5_000_000L); // 500us, 5ms
+ }
+ }
+
+ /**
+ * Executes the next available task.
+ *
+ * @return {@code true} if a task was executed, {@code false} otherwise
+ * @throws IllegalStateException If the current thread is not allowed to execute a task
+ */
+ public boolean executeTask() throws IllegalStateException;
+
+ /**
+ * Executes all queued tasks.
+ *
+ * @return {@code true} if a task was executed, {@code false} otherwise
+ * @throws IllegalStateException If the current thread is not allowed to execute a task
+ */
+ public default boolean executeAll() {
+ if (!this.executeTask()) {
+ return false;
+ }
+
+ while (this.executeTask());
+
+ return true;
+ }
+
+ /**
+ * Waits and executes tasks until the condition returns {@code true}.
+ * <p>
+ * WARNING: This function is <i>not</i> suitable for waiting until a deadline!
+ * Use {@link #executeUntil(long)} or {@link #executeConditionally(BooleanSupplier, long)} instead.
+ * </p>
+ */
+ public default void executeConditionally(final BooleanSupplier condition) {
+ long failures = 0;
+ while (!condition.getAsBoolean()) {
+ if (this.executeTask()) {
+ failures = failures >>> 2;
+ } else {
+ failures = ConcurrentUtil.linearLongBackoff(failures, 100_000L, 10_000_000L); // 100us, 10ms
+ }
+ }
+ }
+
+ /**
+ * Waits and executes tasks until the condition returns {@code true} or {@code System.nanoTime() - deadline >= 0}.
+ */
+ public default void executeConditionally(final BooleanSupplier condition, final long deadline) {
+ long failures = 0;
+ // double check deadline; we don't know how expensive the condition is
+ while ((System.nanoTime() - deadline < 0L) && !condition.getAsBoolean() && (System.nanoTime() - deadline < 0L)) {
+ if (this.executeTask()) {
+ failures = failures >>> 2;
+ } else {
+ failures = ConcurrentUtil.linearLongBackoffDeadline(failures, 100_000L, 10_000_000L, deadline); // 100us, 10ms
+ }
+ }
+ }
+
+ /**
+ * Waits and executes tasks until {@code System.nanoTime() - deadline >= 0}.
+ */
+ public default void executeUntil(final long deadline) {
+ long failures = 0;
+ while (System.nanoTime() - deadline < 0L) {
+ if (this.executeTask()) {
+ failures = failures >>> 2;
+ } else {
+ failures = ConcurrentUtil.linearLongBackoffDeadline(failures, 100_000L, 10_000_000L, deadline); // 100us, 10ms
+ }
+ }
+ }
+
+ /**
+ * Prevent further additions to this queue. Attempts to add after this call has completed (potentially during) will
+ * result in {@link IllegalStateException} being thrown.
+ * <p>
+ * This operation is atomic with respect to other shutdown calls
+ * </p>
+ * <p>
+ * After this call has completed, regardless of return value, this queue will be shutdown.
+ * </p>
+ *
+ * @return {@code true} if the queue was shutdown, {@code false} if it has shut down already
+ * @throws UnsupportedOperationException If this queue does not support shutdown
+ * @see #isShutdown()
+ */
+ public default boolean shutdown() throws UnsupportedOperationException {
+ throw new UnsupportedOperationException();
+ }
+
+ /**
+ * Returns whether this queue has shut down. Effectively, whether new tasks will be rejected - this method
+ * does not indicate whether all the tasks scheduled have been executed.
+ * @return Returns whether this queue has shut down.
+ * @see #waitUntilAllExecuted()
+ */
+ public default boolean isShutdown() {
+ return false;
+ }
+
+ /**
+ * Task object returned for any {@link BaseExecutor} scheduled task.
+ * @see BaseExecutor
+ */
+ public static interface BaseTask extends Cancellable {
+
+ /**
+ * Causes a lazily queued task to become queued or executed
+ *
+ * @throws IllegalStateException If the backing queue has shutdown
+ * @return {@code true} If the task was queued, {@code false} if the task was already queued/cancelled/executed
+ */
+ public boolean queue();
+
+ /**
+ * Forces this task to be marked as completed.
+ *
+ * @return {@code true} if the task was cancelled, {@code false} if the task has already completed or is being completed.
+ */
+ @Override
+ public boolean cancel();
+
+ /**
+ * Executes this task. This will also mark the task as completing.
+ * <p>
+ * Exceptions thrown from the runnable will be rethrown.
+ * </p>
+ *
+ * @return {@code true} if this task was executed, {@code false} if it was already marked as completed.
+ */
+ public boolean execute();
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/executor/Cancellable.java b/src/main/java/ca/spottedleaf/concurrentutil/executor/Cancellable.java
new file mode 100644
index 0000000000000000000000000000000000000000..11449056361bb6c5a055f543cdd135c4113757c6
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/Cancellable.java
@@ -0,0 +1,14 @@
+package ca.spottedleaf.concurrentutil.executor;
+
+/**
+ * Interface specifying that something can be cancelled.
+ */
+public interface Cancellable {
+
+ /**
+ * Tries to cancel this task. If the task is in a stage that is too late to be cancelled, then this function
+ * will return {@code false}. If the task is already cancelled, then this function returns {@code false}. Only
+ * when this function successfully stops this task from being completed will it return {@code true}.
+ */
+ public boolean cancel();
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/DelayedPrioritisedTask.java b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/DelayedPrioritisedTask.java
new file mode 100644
index 0000000000000000000000000000000000000000..3ce10053d4ec51855ad7012abb5d97df1c0e557a
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/DelayedPrioritisedTask.java
@@ -0,0 +1,170 @@
+package ca.spottedleaf.concurrentutil.executor.standard;
+
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import java.lang.invoke.VarHandle;
+
+public class DelayedPrioritisedTask {
+
+ protected volatile int priority;
+ protected static final VarHandle PRIORITY_HANDLE = ConcurrentUtil.getVarHandle(DelayedPrioritisedTask.class, "priority", int.class);
+
+ protected static final int PRIORITY_SET = Integer.MIN_VALUE >>> 0;
+
+ protected final int getPriorityVolatile() {
+ return (int)PRIORITY_HANDLE.getVolatile((DelayedPrioritisedTask)this);
+ }
+
+ protected final int compareAndExchangePriorityVolatile(final int expect, final int update) {
+ return (int)PRIORITY_HANDLE.compareAndExchange((DelayedPrioritisedTask)this, (int)expect, (int)update);
+ }
+
+ protected final int getAndOrPriorityVolatile(final int val) {
+ return (int)PRIORITY_HANDLE.getAndBitwiseOr((DelayedPrioritisedTask)this, (int)val);
+ }
+
+ protected final void setPriorityPlain(final int val) {
+ PRIORITY_HANDLE.set((DelayedPrioritisedTask)this, (int)val);
+ }
+
+ protected volatile PrioritisedExecutor.PrioritisedTask task;
+ protected static final VarHandle TASK_HANDLE = ConcurrentUtil.getVarHandle(DelayedPrioritisedTask.class, "task", PrioritisedExecutor.PrioritisedTask.class);
+
+ protected PrioritisedExecutor.PrioritisedTask getTaskPlain() {
+ return (PrioritisedExecutor.PrioritisedTask)TASK_HANDLE.get((DelayedPrioritisedTask)this);
+ }
+
+ protected PrioritisedExecutor.PrioritisedTask getTaskVolatile() {
+ return (PrioritisedExecutor.PrioritisedTask)TASK_HANDLE.getVolatile((DelayedPrioritisedTask)this);
+ }
+
+ protected final PrioritisedExecutor.PrioritisedTask compareAndExchangeTaskVolatile(final PrioritisedExecutor.PrioritisedTask expect, final PrioritisedExecutor.PrioritisedTask update) {
+ return (PrioritisedExecutor.PrioritisedTask)TASK_HANDLE.compareAndExchange((DelayedPrioritisedTask)this, (PrioritisedExecutor.PrioritisedTask)expect, (PrioritisedExecutor.PrioritisedTask)update);
+ }
+
+ public DelayedPrioritisedTask(final PrioritisedExecutor.Priority priority) {
+ this.setPriorityPlain(priority.priority);
+ }
+
+ // only public for debugging
+ public int getPriorityInternal() {
+ return this.getPriorityVolatile();
+ }
+
+ public PrioritisedExecutor.PrioritisedTask getTask() {
+ return this.getTaskVolatile();
+ }
+
+ public void setTask(final PrioritisedExecutor.PrioritisedTask task) {
+ int priority = this.getPriorityVolatile();
+
+ if (this.compareAndExchangeTaskVolatile(null, task) != null) {
+ throw new IllegalStateException("setTask() called twice");
+ }
+
+ int failures = 0;
+ for (;;) {
+ task.setPriority(PrioritisedExecutor.Priority.getPriority(priority));
+
+ if (priority == (priority = this.compareAndExchangePriorityVolatile(priority, priority | PRIORITY_SET))) {
+ return;
+ }
+
+ ++failures;
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+ }
+ }
+
+ public PrioritisedExecutor.Priority getPriority() {
+ final int priority = this.getPriorityVolatile();
+ if ((priority & PRIORITY_SET) != 0) {
+ return this.task.getPriority();
+ }
+
+ return PrioritisedExecutor.Priority.getPriority(priority);
+ }
+
+ public void raisePriority(final PrioritisedExecutor.Priority priority) {
+ if (!PrioritisedExecutor.Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Invalid priority " + priority);
+ }
+
+ int failures = 0;
+ for (int curr = this.getPriorityVolatile();;) {
+ if ((curr & PRIORITY_SET) != 0) {
+ this.getTaskPlain().raisePriority(priority);
+ return;
+ }
+
+ if (!priority.isLowerPriority(curr)) {
+ return;
+ }
+
+ if (curr == (curr = this.compareAndExchangePriorityVolatile(curr, priority.priority))) {
+ return;
+ }
+
+ // failed, retry
+
+ ++failures;
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+ }
+ }
+
+ public void setPriority(final PrioritisedExecutor.Priority priority) {
+ if (!PrioritisedExecutor.Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Invalid priority " + priority);
+ }
+
+ int failures = 0;
+ for (int curr = this.getPriorityVolatile();;) {
+ if ((curr & PRIORITY_SET) != 0) {
+ this.getTaskPlain().setPriority(priority);
+ return;
+ }
+
+ if (curr == (curr = this.compareAndExchangePriorityVolatile(curr, priority.priority))) {
+ return;
+ }
+
+ // failed, retry
+
+ ++failures;
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+ }
+ }
+
+ public void lowerPriority(final PrioritisedExecutor.Priority priority) {
+ if (!PrioritisedExecutor.Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Invalid priority " + priority);
+ }
+
+ int failures = 0;
+ for (int curr = this.getPriorityVolatile();;) {
+ if ((curr & PRIORITY_SET) != 0) {
+ this.getTaskPlain().lowerPriority(priority);
+ return;
+ }
+
+ if (!priority.isHigherPriority(curr)) {
+ return;
+ }
+
+ if (curr == (curr = this.compareAndExchangePriorityVolatile(curr, priority.priority))) {
+ return;
+ }
+
+ // failed, retry
+
+ ++failures;
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedExecutor.java b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedExecutor.java
new file mode 100644
index 0000000000000000000000000000000000000000..91beb6f23f257cf265fe3150f760892e605f217a
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedExecutor.java
@@ -0,0 +1,276 @@
+package ca.spottedleaf.concurrentutil.executor.standard;
+
+import ca.spottedleaf.concurrentutil.executor.BaseExecutor;
+
+/**
+ * Implementation of {@link BaseExecutor} which schedules tasks to be executed by a given priority.
+ * @see BaseExecutor
+ */
+public interface PrioritisedExecutor extends BaseExecutor {
+
+ public static enum Priority {
+
+ /**
+ * Priority value indicating the task has completed or is being completed.
+ * This priority cannot be used to schedule tasks.
+ */
+ COMPLETING(-1),
+
+ /**
+ * Absolute highest priority, should only be used for when a task is blocking a time-critical thread.
+ */
+ BLOCKING(),
+
+ /**
+ * Should only be used for urgent but not time-critical tasks.
+ */
+ HIGHEST(),
+
+ /**
+ * Two priorities above normal.
+ */
+ HIGHER(),
+
+ /**
+ * One priority above normal.
+ */
+ HIGH(),
+
+ /**
+ * Default priority.
+ */
+ NORMAL(),
+
+ /**
+ * One priority below normal.
+ */
+ LOW(),
+
+ /**
+ * Two priorities below normal.
+ */
+ LOWER(),
+
+ /**
+ * Use for tasks that should eventually execute, but are not needed to.
+ */
+ LOWEST(),
+
+ /**
+ * Use for tasks that can be delayed indefinitely.
+ */
+ IDLE();
+
+ // returns whether the priority can be scheduled
+ public static boolean isValidPriority(final Priority priority) {
+ return priority != null && priority != Priority.COMPLETING;
+ }
+
+ // returns the higher priority of the two
+ public static Priority max(final Priority p1, final Priority p2) {
+ return p1.isHigherOrEqualPriority(p2) ? p1 : p2;
+ }
+
+ // returns the lower priroity of the two
+ public static Priority min(final Priority p1, final Priority p2) {
+ return p1.isLowerOrEqualPriority(p2) ? p1 : p2;
+ }
+
+ public boolean isHigherOrEqualPriority(final Priority than) {
+ return this.priority <= than.priority;
+ }
+
+ public boolean isHigherPriority(final Priority than) {
+ return this.priority < than.priority;
+ }
+
+ public boolean isLowerOrEqualPriority(final Priority than) {
+ return this.priority >= than.priority;
+ }
+
+ public boolean isLowerPriority(final Priority than) {
+ return this.priority > than.priority;
+ }
+
+ public boolean isHigherOrEqualPriority(final int than) {
+ return this.priority <= than;
+ }
+
+ public boolean isHigherPriority(final int than) {
+ return this.priority < than;
+ }
+
+ public boolean isLowerOrEqualPriority(final int than) {
+ return this.priority >= than;
+ }
+
+ public boolean isLowerPriority(final int than) {
+ return this.priority > than;
+ }
+
+ public static boolean isHigherOrEqualPriority(final int priority, final int than) {
+ return priority <= than;
+ }
+
+ public static boolean isHigherPriority(final int priority, final int than) {
+ return priority < than;
+ }
+
+ public static boolean isLowerOrEqualPriority(final int priority, final int than) {
+ return priority >= than;
+ }
+
+ public static boolean isLowerPriority(final int priority, final int than) {
+ return priority > than;
+ }
+
+ static final Priority[] PRIORITIES = Priority.values();
+
+ /** includes special priorities */
+ public static final int TOTAL_PRIORITIES = PRIORITIES.length;
+
+ public static final int TOTAL_SCHEDULABLE_PRIORITIES = TOTAL_PRIORITIES - 1;
+
+ public static Priority getPriority(final int priority) {
+ return PRIORITIES[priority + 1];
+ }
+
+ private static int priorityCounter;
+
+ private static int nextCounter() {
+ return priorityCounter++;
+ }
+
+ public final int priority;
+
+ Priority() {
+ this(nextCounter());
+ }
+
+ Priority(final int priority) {
+ this.priority = priority;
+ }
+ }
+
+ /**
+ * Executes the next available task.
+ * <p>
+ * If there is a task with priority {@link PrioritisedExecutor.Priority#BLOCKING} available, then that such task is executed.
+ * </p>
+ * <p>
+ * If there is a task with priority {@link PrioritisedExecutor.Priority#IDLE} available then that task is only executed
+ * when there are no other tasks available with a higher priority.
+ * </p>
+ * <p>
+ * If there are no tasks that have priority {@link PrioritisedExecutor.Priority#BLOCKING} or {@link PrioritisedExecutor.Priority#IDLE}, then
+ * this function will be biased to execute tasks that have higher priorities.
+ * </p>
+ *
+ * @return {@code true} if a task was executed, {@code false} otherwise
+ * @throws IllegalStateException If the current thread is not allowed to execute a task
+ */
+ @Override
+ public boolean executeTask() throws IllegalStateException;
+
+ /**
+ * Queues or executes a task at {@link Priority#NORMAL} priority.
+ * @param task The task to run.
+ *
+ * @throws IllegalStateException If this queue has shutdown.
+ * @throws NullPointerException If the task is null
+ * @return {@code null} if the current thread immediately executed the task, else returns the prioritised task
+ * associated with the parameter
+ */
+ public default PrioritisedTask queueRunnable(final Runnable task) {
+ return this.queueRunnable(task, Priority.NORMAL);
+ }
+
+ /**
+ * Queues or executes a task.
+ *
+ * @param task The task to run.
+ * @param priority The priority for the task.
+ *
+ * @throws IllegalStateException If this queue has shutdown.
+ * @throws NullPointerException If the task is null
+ * @throws IllegalArgumentException If the priority is invalid.
+ * @return {@code null} if the current thread immediately executed the task, else returns the prioritised task
+ * associated with the parameter
+ */
+ public PrioritisedTask queueRunnable(final Runnable task, final Priority priority);
+
+ /**
+ * Creates, but does not execute or queue the task. The task must later be queued via {@link BaseTask#queue()}.
+ *
+ * @param task The task to run.
+ *
+ * @throws IllegalStateException If this queue has shutdown.
+ * @throws NullPointerException If the task is null
+ * @throws IllegalArgumentException If the priority is invalid.
+ * @throws UnsupportedOperationException If this executor does not support lazily queueing tasks
+ * @return The prioritised task associated with the parameters
+ */
+ public default PrioritisedTask createTask(final Runnable task) {
+ return this.createTask(task, Priority.NORMAL);
+ }
+
+ /**
+ * Creates, but does not execute or queue the task. The task must later be queued via {@link BaseTask#queue()}.
+ *
+ * @param task The task to run.
+ * @param priority The priority for the task.
+ *
+ * @throws IllegalStateException If this queue has shutdown.
+ * @throws NullPointerException If the task is null
+ * @throws IllegalArgumentException If the priority is invalid.
+ * @throws UnsupportedOperationException If this executor does not support lazily queueing tasks
+ * @return The prioritised task associated with the parameters
+ */
+ public PrioritisedTask createTask(final Runnable task, final Priority priority);
+
+ /**
+ * Extension of {@link ca.spottedleaf.concurrentutil.executor.BaseExecutor.BaseTask} which adds functions
+ * to retrieve and modify the task's associated priority.
+ *
+ * @see ca.spottedleaf.concurrentutil.executor.BaseExecutor.BaseTask
+ */
+ public static interface PrioritisedTask extends BaseTask {
+
+ /**
+ * Returns the current priority. Note that {@link Priority#COMPLETING} will be returned
+ * if this task is completing or has completed.
+ */
+ public Priority getPriority();
+
+ /**
+ * Attempts to set this task's priority level to the level specified.
+ *
+ * @param priority Specified priority level.
+ *
+ * @throws IllegalArgumentException If the priority is invalid
+ * @return {@code true} if successful, {@code false} if this task is completing or has completed or the queue
+ * this task was scheduled on was shutdown, or if the priority was already at the specified level.
+ */
+ public boolean setPriority(final Priority priority);
+
+ /**
+ * Attempts to raise the priority to the priority level specified.
+ *
+ * @param priority Priority specified
+ *
+ * @throws IllegalArgumentException If the priority is invalid
+ * @return {@code false} if the current task is completing, {@code true} if the priority was raised to the specified level or was already at the specified level or higher.
+ */
+ public boolean raisePriority(final Priority priority);
+
+ /**
+ * Attempts to lower the priority to the priority level specified.
+ *
+ * @param priority Priority specified
+ *
+ * @throws IllegalArgumentException If the priority is invalid
+ * @return {@code false} if the current task is completing, {@code true} if the priority was lowered to the specified level or was already at the specified level or lower.
+ */
+ public boolean lowerPriority(final Priority priority);
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedQueueExecutorThread.java b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedQueueExecutorThread.java
new file mode 100644
index 0000000000000000000000000000000000000000..d1683ba6350e530373944f98192c0f2baf241e70
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedQueueExecutorThread.java
@@ -0,0 +1,301 @@
+package ca.spottedleaf.concurrentutil.executor.standard;
+
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.lang.invoke.VarHandle;
+import java.util.concurrent.locks.LockSupport;
+
+/**
+ * Thread which will continuously drain from a specified queue.
+ * <p>
+ * Note: When using this thread, queue additions to the underlying {@link #queue} are not sufficient to get this thread
+ * to execute the task. The function {@link #notifyTasks()} must be used after scheduling a task. For expected behaviour
+ * of task scheduling (thread wakes up after tasks are scheduled), use the methods provided on {@link PrioritisedExecutor}
+ * methods.
+ * </p>
+ */
+public class PrioritisedQueueExecutorThread extends Thread implements PrioritisedExecutor {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(PrioritisedQueueExecutorThread.class);
+
+ protected final PrioritisedExecutor queue;
+
+ protected volatile boolean threadShutdown;
+
+ protected volatile boolean threadParked;
+ protected static final VarHandle THREAD_PARKED_HANDLE = ConcurrentUtil.getVarHandle(PrioritisedQueueExecutorThread.class, "threadParked", boolean.class);
+
+ protected volatile boolean halted;
+
+ protected final long spinWaitTime;
+
+ static final long DEFAULT_SPINWAIT_TIME = (long)(0.1e6);// 0.1ms
+
+ public PrioritisedQueueExecutorThread(final PrioritisedExecutor queue) {
+ this(queue, DEFAULT_SPINWAIT_TIME); // 0.1ms
+ }
+
+ public PrioritisedQueueExecutorThread(final PrioritisedExecutor queue, final long spinWaitTime) { // in ns
+ this.queue = queue;
+ this.spinWaitTime = spinWaitTime;
+ }
+
+ @Override
+ public void run() {
+ final long spinWaitTime = this.spinWaitTime;
+
+ main_loop:
+ for (;;) {
+ this.pollTasks();
+
+ // spinwait
+
+ final long start = System.nanoTime();
+
+ for (;;) {
+ // If we are interrupted for any reason, park() will always return immediately. Clear so that we don't needlessly use cpu in such an event.
+ Thread.interrupted();
+ Thread.yield();
+ LockSupport.parkNanos("Spinwaiting on tasks", 10_000L); // 10us
+
+ if (this.pollTasks()) {
+ // restart loop, found tasks
+ continue main_loop;
+ }
+
+ if (this.handleClose()) {
+ return; // we're done
+ }
+
+ if ((System.nanoTime() - start) >= spinWaitTime) {
+ break;
+ }
+ }
+
+ if (this.handleClose()) {
+ return;
+ }
+
+ this.setThreadParkedVolatile(true);
+
+ // We need to parse here to avoid a race condition where a thread queues a task before we set parked to true
+ // (i.e it will not notify us)
+ if (this.pollTasks()) {
+ this.setThreadParkedVolatile(false);
+ continue;
+ }
+
+ if (this.handleClose()) {
+ return;
+ }
+
+ // we don't need to check parked before sleeping, but we do need to check parked in a do-while loop
+ // LockSupport.park() can fail for any reason
+ while (this.getThreadParkedVolatile()) {
+ Thread.interrupted();
+ LockSupport.park("Waiting on tasks");
+ }
+ }
+ }
+
+ /**
+ * Attempts to poll as many tasks as possible, returning when finished.
+ * @return Whether any tasks were executed.
+ */
+ protected boolean pollTasks() {
+ boolean ret = false;
+
+ for (;;) {
+ if (this.halted) {
+ break;
+ }
+ try {
+ if (!this.queue.executeTask()) {
+ break;
+ }
+ ret = true;
+ } catch (final ThreadDeath death) {
+ throw death; // goodbye world...
+ } catch (final Throwable throwable) {
+ LOGGER.error("Exception thrown from prioritized runnable task in thread '" + this.getName() + "'", throwable);
+ }
+ }
+
+ return ret;
+ }
+
+ protected boolean handleClose() {
+ if (this.threadShutdown) {
+ this.pollTasks(); // this ensures we've emptied the queue
+ return true;
+ }
+ return false;
+ }
+
+ /**
+ * Notify this thread that a task has been added to its queue
+ * @return {@code true} if this thread was waiting for tasks, {@code false} if it is executing tasks
+ */
+ public boolean notifyTasks() {
+ if (this.getThreadParkedVolatile() && this.exchangeThreadParkedVolatile(false)) {
+ LockSupport.unpark(this);
+ return true;
+ }
+ return false;
+ }
+
+ @Override
+ public PrioritisedTask createTask(final Runnable task, final Priority priority) {
+ final PrioritisedTask queueTask = this.queue.createTask(task, priority);
+
+ // need to override queue() to notify us of tasks
+ return new PrioritisedTask() {
+ @Override
+ public Priority getPriority() {
+ return queueTask.getPriority();
+ }
+
+ @Override
+ public boolean setPriority(final Priority priority) {
+ return queueTask.setPriority(priority);
+ }
+
+ @Override
+ public boolean raisePriority(final Priority priority) {
+ return queueTask.raisePriority(priority);
+ }
+
+ @Override
+ public boolean lowerPriority(final Priority priority) {
+ return queueTask.lowerPriority(priority);
+ }
+
+ @Override
+ public boolean queue() {
+ final boolean ret = queueTask.queue();
+ if (ret) {
+ PrioritisedQueueExecutorThread.this.notifyTasks();
+ }
+ return ret;
+ }
+
+ @Override
+ public boolean cancel() {
+ return queueTask.cancel();
+ }
+
+ @Override
+ public boolean execute() {
+ return queueTask.execute();
+ }
+ };
+ }
+
+ @Override
+ public PrioritisedTask queueRunnable(final Runnable task, final Priority priority) {
+ final PrioritisedTask ret = this.queue.queueRunnable(task, priority);
+
+ this.notifyTasks();
+
+ return ret;
+ }
+
+ @Override
+ public boolean haveAllTasksExecuted() {
+ return this.queue.haveAllTasksExecuted();
+ }
+
+ @Override
+ public long getTotalTasksExecuted() {
+ return this.queue.getTotalTasksExecuted();
+ }
+
+ @Override
+ public long getTotalTasksScheduled() {
+ return this.queue.getTotalTasksScheduled();
+ }
+
+ /**
+ * {@inheritDoc}
+ * @throws IllegalStateException If the current thread is {@code this} thread, or the underlying queue throws this exception.
+ */
+ @Override
+ public void waitUntilAllExecuted() throws IllegalStateException {
+ if (Thread.currentThread() == this) {
+ throw new IllegalStateException("Cannot block on our own queue");
+ }
+ this.queue.waitUntilAllExecuted();
+ }
+
+ /**
+ * {@inheritDoc}
+ * @throws IllegalStateException Always
+ */
+ @Override
+ public boolean executeTask() throws IllegalStateException {
+ throw new IllegalStateException();
+ }
+
+ /**
+ * Closes this queue executor's queue. Optionally waits for all tasks in queue to be executed if {@code wait} is true.
+ * <p>
+ * This function is MT-Safe.
+ * </p>
+ * @param wait If this call is to wait until the queue is empty and there are no tasks executing in the queue.
+ * @param killQueue Whether to shutdown this thread's queue
+ * @return whether this thread shut down the queue
+ * @see #halt(boolean)
+ */
+ public boolean close(final boolean wait, final boolean killQueue) {
+ final boolean ret = killQueue && this.queue.shutdown();
+ this.threadShutdown = true;
+
+ // force thread to respond to the shutdown
+ this.setThreadParkedVolatile(false);
+ LockSupport.unpark(this);
+
+ if (wait) {
+ this.waitUntilAllExecuted();
+ }
+
+ return ret;
+ }
+
+
+ /**
+ * Causes this thread to exit without draining the queue. To ensure tasks are completed, use {@link #close(boolean, boolean)}.
+ * <p>
+ * This is not safe to call with {@link #close(boolean, boolean)} if <code>wait = true</code>, in which case
+ * the waiting thread may block indefinitely.
+ * </p>
+ * <p>
+ * This function is MT-Safe.
+ * </p>
+ * @param killQueue Whether to shutdown this thread's queue
+ * @see #close(boolean, boolean)
+ */
+ public void halt(final boolean killQueue) {
+ if (killQueue) {
+ this.queue.shutdown();
+ }
+ this.threadShutdown = true;
+ this.halted = true;
+
+ // force thread to respond to the shutdown
+ this.setThreadParkedVolatile(false);
+ LockSupport.unpark(this);
+ }
+
+ protected final boolean getThreadParkedVolatile() {
+ return (boolean)THREAD_PARKED_HANDLE.getVolatile(this);
+ }
+
+ protected final boolean exchangeThreadParkedVolatile(final boolean value) {
+ return (boolean)THREAD_PARKED_HANDLE.getAndSet(this, value);
+ }
+
+ protected final void setThreadParkedVolatile(final boolean value) {
+ THREAD_PARKED_HANDLE.setVolatile(this, value);
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedThreadPool.java b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedThreadPool.java
new file mode 100644
index 0000000000000000000000000000000000000000..2ba36e29d0d8693f2f5e6c6d195ca27f2a5099aa
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedThreadPool.java
@@ -0,0 +1,632 @@
+package ca.spottedleaf.concurrentutil.executor.standard;
+
+import it.unimi.dsi.fastutil.objects.ReferenceOpenHashSet;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.TreeSet;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.BiConsumer;
+
+public final class PrioritisedThreadPool {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(PrioritisedThreadPool.class);
+
+ private final PrioritisedThread[] threads;
+ private final TreeSet<PrioritisedPoolExecutorImpl> queues = new TreeSet<>(PrioritisedPoolExecutorImpl.comparator());
+ private final String name;
+ private final long queueMaxHoldTime;
+
+ private final ReferenceOpenHashSet<PrioritisedPoolExecutorImpl> nonShutdownQueues = new ReferenceOpenHashSet<>();
+ private final ReferenceOpenHashSet<PrioritisedPoolExecutorImpl> activeQueues = new ReferenceOpenHashSet<>();
+
+ private boolean shutdown;
+
+ private long schedulingIdGenerator;
+
+ private static final long DEFAULT_QUEUE_HOLD_TIME = (long)(5.0e6);
+
+ /**
+ * @param name Specified debug name of this thread pool
+ * @param threads The number of threads to use
+ */
+ public PrioritisedThreadPool(final String name, final int threads) {
+ this(name, threads, null);
+ }
+
+ /**
+ * @param name Specified debug name of this thread pool
+ * @param threads The number of threads to use
+ * @param threadModifier Invoked for each created thread with its incremental id before starting them
+ */
+ public PrioritisedThreadPool(final String name, final int threads, final BiConsumer<Thread, Integer> threadModifier) {
+ this(name, threads, threadModifier, DEFAULT_QUEUE_HOLD_TIME); // 5ms
+ }
+
+ /**
+ * @param name Specified debug name of this thread pool
+ * @param threads The number of threads to use
+ * @param threadModifier Invoked for each created thread with its incremental id before starting them
+ * @param queueHoldTime The maximum amount of time to spend executing tasks in a specific queue before attempting
+ * to switch to another queue, per thread
+ */
+ public PrioritisedThreadPool(final String name, final int threads, final BiConsumer<Thread, Integer> threadModifier,
+ final long queueHoldTime) { // in ns
+ if (threads <= 0) {
+ throw new IllegalArgumentException("Thread count must be > 0, not " + threads);
+ }
+ if (name == null) {
+ throw new IllegalArgumentException("Name cannot be null");
+ }
+ this.name = name;
+ this.queueMaxHoldTime = queueHoldTime;
+
+ this.threads = new PrioritisedThread[threads];
+ for (int i = 0; i < threads; ++i) {
+ this.threads[i] = new PrioritisedThread(this);
+
+ // set default attributes
+ this.threads[i].setName("Prioritised thread for pool '" + name + "' #" + i);
+ this.threads[i].setUncaughtExceptionHandler((final Thread thread, final Throwable throwable) -> {
+ LOGGER.error("Uncaught exception in thread " + thread.getName(), throwable);
+ });
+
+ // let thread modifier override defaults
+ if (threadModifier != null) {
+ threadModifier.accept(this.threads[i], Integer.valueOf(i));
+ }
+
+ // now the thread can start
+ this.threads[i].start();
+ }
+ }
+
+ /**
+ * Returns an array representing the threads backing this thread pool.
+ */
+ public Thread[] getThreads() {
+ return Arrays.copyOf(this.threads, this.threads.length, Thread[].class);
+ }
+
+ /**
+ * Creates and returns a {@link PrioritisedPoolExecutor} to schedule tasks onto. The returned executor will execute
+ * tasks on this thread pool only.
+ * @param name The debug name of the executor.
+ * @param minParallelism The minimum number of threads to be executing tasks from the returned executor
+ * before threads may be allocated to other queues in this thread pool.
+ * @param parallelism The maximum number of threads which may be executing tasks from the returned executor.
+ * @throws IllegalStateException If this thread pool is shut down
+ */
+ public PrioritisedPoolExecutor createExecutor(final String name, final int minParallelism, final int parallelism) {
+ synchronized (this.nonShutdownQueues) {
+ if (this.shutdown) {
+ throw new IllegalStateException("Queue is shutdown: " + this.toString());
+ }
+ final PrioritisedPoolExecutorImpl ret = new PrioritisedPoolExecutorImpl(
+ this, name,
+ Math.min(Math.max(1, parallelism), this.threads.length),
+ Math.min(Math.max(0, minParallelism), this.threads.length)
+ );
+
+ this.nonShutdownQueues.add(ret);
+
+ synchronized (this.activeQueues) {
+ this.activeQueues.add(ret);
+ }
+
+ return ret;
+ }
+ }
+
+ /**
+ * Prevents creation of new queues, shutdowns all non-shutdown queues if specified
+ */
+ public void halt(final boolean shutdownQueues) {
+ synchronized (this.nonShutdownQueues) {
+ this.shutdown = true;
+ }
+ if (shutdownQueues) {
+ final ArrayList<PrioritisedPoolExecutorImpl> queuesToShutdown;
+ synchronized (this.nonShutdownQueues) {
+ this.shutdown = true;
+ queuesToShutdown = new ArrayList<>(this.nonShutdownQueues);
+ }
+
+ for (final PrioritisedPoolExecutorImpl queue : queuesToShutdown) {
+ queue.shutdown();
+ }
+ }
+
+
+ for (final PrioritisedThread thread : this.threads) {
+ // can't kill queue, queue is null
+ thread.halt(false);
+ }
+ }
+
+ /**
+ * Waits until all threads in this pool have shutdown, or until the specified time has passed.
+ * @param msToWait Maximum time to wait.
+ * @return {@code false} if the maximum time passed, {@code true} otherwise.
+ */
+ public boolean join(final long msToWait) {
+ try {
+ return this.join(msToWait, false);
+ } catch (final InterruptedException ex) {
+ throw new IllegalStateException(ex);
+ }
+ }
+
+ /**
+ * Waits until all threads in this pool have shutdown, or until the specified time has passed.
+ * @param msToWait Maximum time to wait.
+ * @return {@code false} if the maximum time passed, {@code true} otherwise.
+ * @throws InterruptedException If this thread is interrupted.
+ */
+ public boolean joinInterruptable(final long msToWait) throws InterruptedException {
+ return this.join(msToWait, true);
+ }
+
+ protected final boolean join(final long msToWait, final boolean interruptable) throws InterruptedException {
+ final long nsToWait = msToWait * (1000 * 1000);
+ final long start = System.nanoTime();
+ final long deadline = start + nsToWait;
+ boolean interrupted = false;
+ try {
+ for (final PrioritisedThread thread : this.threads) {
+ for (;;) {
+ if (!thread.isAlive()) {
+ break;
+ }
+ final long current = System.nanoTime();
+ if (current >= deadline) {
+ return false;
+ }
+
+ try {
+ thread.join(Math.max(1L, (deadline - current) / (1000 * 1000)));
+ } catch (final InterruptedException ex) {
+ if (interruptable) {
+ throw ex;
+ }
+ interrupted = true;
+ }
+ }
+ }
+
+ return true;
+ } finally {
+ if (interrupted) {
+ Thread.currentThread().interrupt();
+ }
+ }
+ }
+
+ /**
+ * Shuts down this thread pool, optionally waiting for all tasks to be executed.
+ * This function will invoke {@link PrioritisedPoolExecutor#shutdown()} on all created executors on this
+ * thread pool.
+ * @param wait Whether to wait for tasks to be executed
+ */
+ public void shutdown(final boolean wait) {
+ final ArrayList<PrioritisedPoolExecutorImpl> queuesToShutdown;
+ synchronized (this.nonShutdownQueues) {
+ this.shutdown = true;
+ queuesToShutdown = new ArrayList<>(this.nonShutdownQueues);
+ }
+
+ for (final PrioritisedPoolExecutorImpl queue : queuesToShutdown) {
+ queue.shutdown();
+ }
+
+ for (final PrioritisedThread thread : this.threads) {
+ // none of these can be true or else NPE
+ thread.close(false, false);
+ }
+
+ if (wait) {
+ final ArrayList<PrioritisedPoolExecutorImpl> queues;
+ synchronized (this.activeQueues) {
+ queues = new ArrayList<>(this.activeQueues);
+ }
+ for (final PrioritisedPoolExecutorImpl queue : queues) {
+ queue.waitUntilAllExecuted();
+ }
+ }
+ }
+
+ protected static final class PrioritisedThread extends PrioritisedQueueExecutorThread {
+
+ protected final PrioritisedThreadPool pool;
+ protected final AtomicBoolean alertedHighPriority = new AtomicBoolean();
+
+ public PrioritisedThread(final PrioritisedThreadPool pool) {
+ super(null);
+ this.pool = pool;
+ }
+
+ public boolean alertHighPriorityExecutor() {
+ if (!this.notifyTasks()) {
+ if (!this.alertedHighPriority.get()) {
+ this.alertedHighPriority.set(true);
+ }
+ return false;
+ }
+
+ return true;
+ }
+
+ private boolean isAlertedHighPriority() {
+ return this.alertedHighPriority.get() && this.alertedHighPriority.getAndSet(false);
+ }
+
+ @Override
+ protected boolean pollTasks() {
+ final PrioritisedThreadPool pool = this.pool;
+ final TreeSet<PrioritisedPoolExecutorImpl> queues = this.pool.queues;
+
+ boolean ret = false;
+ for (;;) {
+ if (this.halted) {
+ break;
+ }
+ // try to find a queue
+ // note that if and ONLY IF the queues set is empty, this means there are no tasks for us to execute.
+ // so we can only break when it's empty
+ final PrioritisedPoolExecutorImpl queue;
+ // select queue
+ synchronized (queues) {
+ queue = queues.pollFirst();
+ if (queue == null) {
+ // no tasks to execute
+ break;
+ }
+
+ queue.schedulingId = ++pool.schedulingIdGenerator;
+ // we own this queue now, so increment the executor count
+ // do we also need to push this queue up for grabs for another executor?
+ if (++queue.concurrentExecutors < queue.maximumExecutors) {
+ // re-add to queues
+ // it's very important this is done in the same synchronised block for polling, as this prevents
+ // us from possibly later adding a queue that should not exist in the set
+ queues.add(queue);
+ queue.isQueued = true;
+ } else {
+ queue.isQueued = false;
+ }
+ // note: we cannot drain entries from the queue while holding this lock, as it will cause deadlock
+ // the queue addition holds the per-queue lock first then acquires the lock we have now, but if we
+ // try to poll now we don't hold the per queue lock but we do hold the global lock...
+ }
+
+ // parse tasks as long as we are allowed
+ final long start = System.nanoTime();
+ final long deadline = start + pool.queueMaxHoldTime;
+ do {
+ try {
+ if (this.halted) {
+ break;
+ }
+ if (!queue.executeTask()) {
+ // no more tasks, try next queue
+ break;
+ }
+ ret = true;
+ } catch (final ThreadDeath death) {
+ throw death; // goodbye world...
+ } catch (final Throwable throwable) {
+ LOGGER.error("Exception thrown from thread '" + this.getName() + "' in queue '" + queue.toString() + "'", throwable);
+ }
+ } while (!this.isAlertedHighPriority() && System.nanoTime() <= deadline);
+
+ synchronized (queues) {
+ // decrement executors, we are no longer executing
+ if (queue.isQueued) {
+ queues.remove(queue);
+ queue.isQueued = false;
+ }
+ if (--queue.concurrentExecutors == 0 && queue.scheduledPriority == null) {
+ // reset scheduling id once the queue is empty again
+ // this will ensure empty queues are not prioritised suddenly over active queues once tasks are
+ // queued
+ queue.schedulingId = 0L;
+ }
+
+ // ensure the executor is queued for execution again
+ if (!queue.isHalted && queue.scheduledPriority != null) { // make sure it actually has tasks
+ queues.add(queue);
+ queue.isQueued = true;
+ }
+ }
+ }
+
+ return ret;
+ }
+ }
+
+ public interface PrioritisedPoolExecutor extends PrioritisedExecutor {
+
+ /**
+ * Removes this queue from the thread pool without shutting the queue down or waiting for queued tasks to be executed
+ */
+ public void halt();
+
+ /**
+ * Returns whether this executor is scheduled to run tasks or is running tasks, otherwise it returns whether
+ * this queue is not halted and not shutdown.
+ */
+ public boolean isActive();
+ }
+
+ protected static final class PrioritisedPoolExecutorImpl extends PrioritisedThreadedTaskQueue implements PrioritisedPoolExecutor {
+
+ protected final PrioritisedThreadPool pool;
+ protected final long[] priorityCounts = new long[Priority.TOTAL_SCHEDULABLE_PRIORITIES];
+ protected long schedulingId;
+ protected int concurrentExecutors;
+ protected Priority scheduledPriority;
+
+ protected final String name;
+ protected final int maximumExecutors;
+ protected final int minimumExecutors;
+ protected boolean isQueued;
+
+ public PrioritisedPoolExecutorImpl(final PrioritisedThreadPool pool, final String name, final int maximumExecutors, final int minimumExecutors) {
+ this.pool = pool;
+ this.name = name;
+ this.maximumExecutors = maximumExecutors;
+ this.minimumExecutors = minimumExecutors;
+ }
+
+ public static Comparator<PrioritisedPoolExecutorImpl> comparator() {
+ return (final PrioritisedPoolExecutorImpl p1, final PrioritisedPoolExecutorImpl p2) -> {
+ if (p1 == p2) {
+ return 0;
+ }
+
+ final int belowMin1 = p1.minimumExecutors - p1.concurrentExecutors;
+ final int belowMin2 = p2.minimumExecutors - p2.concurrentExecutors;
+
+ // test minimum executors
+ if (belowMin1 > 0 || belowMin2 > 0) {
+ // want the largest belowMin to be first
+ final int minCompare = Integer.compare(belowMin2, belowMin1);
+
+ if (minCompare != 0) {
+ return minCompare;
+ }
+ }
+
+ // prefer higher priority
+ final int priorityCompare = p1.scheduledPriority.ordinal() - p2.scheduledPriority.ordinal();
+ if (priorityCompare != 0) {
+ return priorityCompare;
+ }
+
+ // try to spread out the executors so that each can have threads executing
+ final int executorCompare = p1.concurrentExecutors - p2.concurrentExecutors;
+ if (executorCompare != 0) {
+ return executorCompare;
+ }
+
+ // if all else fails here we just choose whichever executor was queued first
+ return Long.compare(p1.schedulingId, p2.schedulingId);
+ };
+ }
+
+ private boolean isHalted;
+
+ @Override
+ public void halt() {
+ final PrioritisedThreadPool pool = this.pool;
+ final TreeSet<PrioritisedPoolExecutorImpl> queues = pool.queues;
+ synchronized (queues) {
+ if (this.isHalted) {
+ return;
+ }
+ this.isHalted = true;
+ if (this.isQueued) {
+ queues.remove(this);
+ this.isQueued = false;
+ }
+ }
+ synchronized (pool.nonShutdownQueues) {
+ pool.nonShutdownQueues.remove(this);
+ }
+ synchronized (pool.activeQueues) {
+ pool.activeQueues.remove(this);
+ }
+ }
+
+ @Override
+ public boolean isActive() {
+ final PrioritisedThreadPool pool = this.pool;
+ final TreeSet<PrioritisedPoolExecutorImpl> queues = pool.queues;
+
+ synchronized (queues) {
+ if (this.concurrentExecutors != 0) {
+ return true;
+ }
+ synchronized (pool.activeQueues) {
+ if (pool.activeQueues.contains(this)) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+ }
+
+ private long totalQueuedTasks = 0L;
+
+ @Override
+ protected void priorityChange(final PrioritisedThreadedTaskQueue.PrioritisedTask task, final Priority from, final Priority to) {
+ // Note: The superclass' queue lock is ALWAYS held when inside this method. So we do NOT need to do any additional synchronisation
+ // for accessing this queue's state.
+ final long[] priorityCounts = this.priorityCounts;
+ final boolean shutdown = this.isShutdown();
+
+ if (from == null && to == Priority.COMPLETING) {
+ throw new IllegalStateException("Cannot complete task without queueing it first");
+ }
+
+ // we should only notify for queueing of tasks, not changing priorities
+ final boolean shouldNotifyTasks = from == null;
+
+ final Priority scheduledPriority = this.scheduledPriority;
+ if (from != null) {
+ --priorityCounts[from.priority];
+ }
+ if (to != Priority.COMPLETING) {
+ ++priorityCounts[to.priority];
+ }
+ final long totalQueuedTasks;
+ if (to == Priority.COMPLETING) {
+ totalQueuedTasks = --this.totalQueuedTasks;
+ } else if (from == null) {
+ totalQueuedTasks = ++this.totalQueuedTasks;
+ } else {
+ totalQueuedTasks = this.totalQueuedTasks;
+ }
+
+ // find new highest priority
+ int highest = Math.min(to == Priority.COMPLETING ? Priority.IDLE.priority : to.priority, scheduledPriority == null ? Priority.IDLE.priority : scheduledPriority.priority);
+ int lowestPriority = priorityCounts.length; // exclusive
+ for (;highest < lowestPriority; ++highest) {
+ final long count = priorityCounts[highest];
+ if (count < 0) {
+ throw new IllegalStateException("Priority " + highest + " has " + count + " scheduled tasks");
+ }
+
+ if (count != 0) {
+ break;
+ }
+ }
+
+ final Priority newPriority;
+ if (highest == lowestPriority) {
+ // no tasks left
+ newPriority = null;
+ } else if (shutdown) {
+ // whichever is lower, the actual greatest priority or simply HIGHEST
+ // this is so shutdown automatically gets priority
+ newPriority = Priority.getPriority(Math.min(highest, Priority.HIGHEST.priority));
+ } else {
+ newPriority = Priority.getPriority(highest);
+ }
+
+ final int executorsWanted;
+ boolean shouldNotifyHighPriority = false;
+
+ final PrioritisedThreadPool pool = this.pool;
+ final TreeSet<PrioritisedPoolExecutorImpl> queues = pool.queues;
+
+ synchronized (queues) {
+ if (!this.isQueued) {
+ // see if we need to be queued
+ if (newPriority != null) {
+ if (this.schedulingId == 0L) {
+ this.schedulingId = ++pool.schedulingIdGenerator;
+ }
+ this.scheduledPriority = newPriority; // must be updated before queue add
+ if (!this.isHalted && this.concurrentExecutors < this.maximumExecutors) {
+ shouldNotifyHighPriority = newPriority.isHigherOrEqualPriority(Priority.HIGH);
+ queues.add(this);
+ this.isQueued = true;
+ }
+ } else {
+ // do not queue
+ this.scheduledPriority = null;
+ }
+ } else {
+ // see if we need to NOT be queued
+ if (newPriority == null) {
+ queues.remove(this);
+ this.scheduledPriority = null;
+ this.isQueued = false;
+ } else if (scheduledPriority != newPriority) {
+ // if our priority changed, we need to update it - which means removing and re-adding into the queue
+ queues.remove(this);
+ // only now can we update scheduledPriority, since we are no longer in queue
+ this.scheduledPriority = newPriority;
+ queues.add(this);
+ shouldNotifyHighPriority = (scheduledPriority == null || scheduledPriority.isLowerPriority(Priority.HIGH)) && newPriority.isHigherOrEqualPriority(Priority.HIGH);
+ }
+ }
+
+ if (this.isQueued) {
+ executorsWanted = Math.min(this.maximumExecutors - this.concurrentExecutors, (int)totalQueuedTasks);
+ } else {
+ executorsWanted = 0;
+ }
+ }
+
+ if (newPriority == null && shutdown) {
+ synchronized (pool.activeQueues) {
+ pool.activeQueues.remove(this);
+ }
+ }
+
+ // Wake up the number of executors we want
+ if (executorsWanted > 0 || (shouldNotifyTasks | shouldNotifyHighPriority)) {
+ int notified = 0;
+ for (final PrioritisedThread thread : pool.threads) {
+ if ((shouldNotifyHighPriority ? thread.alertHighPriorityExecutor() : thread.notifyTasks())
+ && (++notified >= executorsWanted)) {
+ break;
+ }
+ }
+ }
+ }
+
+ @Override
+ public boolean shutdown() {
+ final boolean ret = super.shutdown();
+ if (!ret) {
+ return ret;
+ }
+
+ final PrioritisedThreadPool pool = this.pool;
+
+ // remove from active queues
+ synchronized (pool.nonShutdownQueues) {
+ pool.nonShutdownQueues.remove(this);
+ }
+
+ final TreeSet<PrioritisedPoolExecutorImpl> queues = pool.queues;
+
+ // try and shift around our priority
+ synchronized (queues) {
+ if (this.scheduledPriority == null) {
+ // no tasks are queued, ensure we aren't in activeQueues
+ synchronized (pool.activeQueues) {
+ pool.activeQueues.remove(this);
+ }
+
+ return ret;
+ }
+
+ // try to set scheduled priority to HIGHEST so it drains faster
+
+ if (this.scheduledPriority.isHigherOrEqualPriority(Priority.HIGHEST)) {
+ // already at target priority (highest or above)
+ return ret;
+ }
+
+ // shift priority to HIGHEST
+
+ if (this.isQueued) {
+ queues.remove(this);
+ this.scheduledPriority = Priority.HIGHEST;
+ queues.add(this);
+ } else {
+ this.scheduledPriority = Priority.HIGHEST;
+ }
+ }
+
+ return ret;
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedThreadedTaskQueue.java b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedThreadedTaskQueue.java
new file mode 100644
index 0000000000000000000000000000000000000000..3e8401b1b1f833c4f01bc87059a2f48d761d989f
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedThreadedTaskQueue.java
@@ -0,0 +1,378 @@
+package ca.spottedleaf.concurrentutil.executor.standard;
+
+import java.util.ArrayDeque;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class PrioritisedThreadedTaskQueue implements PrioritisedExecutor {
+
+ protected final ArrayDeque<PrioritisedTask>[] queues = new ArrayDeque[Priority.TOTAL_SCHEDULABLE_PRIORITIES]; {
+ for (int i = 0; i < Priority.TOTAL_SCHEDULABLE_PRIORITIES; ++i) {
+ this.queues[i] = new ArrayDeque<>();
+ }
+ }
+
+ // Use AtomicLong to separate from the queue field, we don't want false sharing here.
+ protected final AtomicLong totalScheduledTasks = new AtomicLong();
+ protected final AtomicLong totalCompletedTasks = new AtomicLong();
+
+ // this is here to prevent failures to queue stalling flush() calls (as the schedule calls would increment totalScheduledTasks without this check)
+ protected volatile boolean hasShutdown;
+
+ protected long taskIdGenerator = 0;
+
+ @Override
+ public PrioritisedExecutor.PrioritisedTask queueRunnable(final Runnable task, final Priority priority) throws IllegalStateException, IllegalArgumentException {
+ if (!Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Priority " + priority + " is invalid");
+ }
+ if (task == null) {
+ throw new NullPointerException("Task cannot be null");
+ }
+
+ if (this.hasShutdown) {
+ // prevent us from stalling flush() calls by incrementing scheduled tasks when we really didn't schedule something
+ throw new IllegalStateException("Queue has shutdown");
+ }
+
+ final PrioritisedTask ret;
+
+ synchronized (this.queues) {
+ if (this.hasShutdown) {
+ throw new IllegalStateException("Queue has shutdown");
+ }
+ this.getAndAddTotalScheduledTasksVolatile(1L);
+
+ ret = new PrioritisedTask(this.taskIdGenerator++, task, priority, this);
+
+ this.queues[ret.priority.priority].add(ret);
+
+ // call priority change callback (note: only after we successfully queue!)
+ this.priorityChange(ret, null, priority);
+ }
+
+ return ret;
+ }
+
+ @Override
+ public PrioritisedExecutor.PrioritisedTask createTask(final Runnable task, final Priority priority) {
+ if (!Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Priority " + priority + " is invalid");
+ }
+ if (task == null) {
+ throw new NullPointerException("Task cannot be null");
+ }
+
+ return new PrioritisedTask(task, priority, this);
+ }
+
+ @Override
+ public long getTotalTasksScheduled() {
+ return this.totalScheduledTasks.get();
+ }
+
+ @Override
+ public long getTotalTasksExecuted() {
+ return this.totalCompletedTasks.get();
+ }
+
+ // callback method for subclasses to override
+ // from is null when a task is immediately created
+ protected void priorityChange(final PrioritisedTask task, final Priority from, final Priority to) {}
+
+ /**
+ * Polls the highest priority task currently available. {@code null} if none. This will mark the
+ * returned task as completed.
+ */
+ protected PrioritisedTask poll() {
+ return this.poll(Priority.IDLE);
+ }
+
+ protected PrioritisedTask poll(final Priority minPriority) {
+ final ArrayDeque<PrioritisedTask>[] queues = this.queues;
+ synchronized (queues) {
+ final int max = minPriority.priority;
+ for (int i = 0; i <= max; ++i) {
+ final ArrayDeque<PrioritisedTask> queue = queues[i];
+ PrioritisedTask task;
+ while ((task = queue.pollFirst()) != null) {
+ if (task.trySetCompleting(i)) {
+ return task;
+ }
+ }
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * Polls and executes the highest priority task currently available. Exceptions thrown during task execution will
+ * be rethrown.
+ * @return {@code true} if a task was executed, {@code false} otherwise.
+ */
+ @Override
+ public boolean executeTask() {
+ final PrioritisedTask task = this.poll();
+
+ if (task != null) {
+ task.executeInternal();
+ return true;
+ }
+
+ return false;
+ }
+
+ @Override
+ public boolean shutdown() {
+ synchronized (this.queues) {
+ if (this.hasShutdown) {
+ return false;
+ }
+ this.hasShutdown = true;
+ }
+ return true;
+ }
+
+ @Override
+ public boolean isShutdown() {
+ return this.hasShutdown;
+ }
+
+ /* totalScheduledTasks */
+
+ protected final long getTotalScheduledTasksVolatile() {
+ return this.totalScheduledTasks.get();
+ }
+
+ protected final long getAndAddTotalScheduledTasksVolatile(final long value) {
+ return this.totalScheduledTasks.getAndAdd(value);
+ }
+
+ /* totalCompletedTasks */
+
+ protected final long getTotalCompletedTasksVolatile() {
+ return this.totalCompletedTasks.get();
+ }
+
+ protected final long getAndAddTotalCompletedTasksVolatile(final long value) {
+ return this.totalCompletedTasks.getAndAdd(value);
+ }
+
+ protected static final class PrioritisedTask implements PrioritisedExecutor.PrioritisedTask {
+ protected final PrioritisedThreadedTaskQueue queue;
+ protected long id;
+ protected static final long NOT_SCHEDULED_ID = -1L;
+
+ protected Runnable runnable;
+ protected volatile Priority priority;
+
+ protected PrioritisedTask(final long id, final Runnable runnable, final Priority priority, final PrioritisedThreadedTaskQueue queue) {
+ if (!Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Invalid priority " + priority);
+ }
+
+ this.priority = priority;
+ this.runnable = runnable;
+ this.queue = queue;
+ this.id = id;
+ }
+
+ protected PrioritisedTask(final Runnable runnable, final Priority priority, final PrioritisedThreadedTaskQueue queue) {
+ if (!Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Invalid priority " + priority);
+ }
+
+ this.priority = priority;
+ this.runnable = runnable;
+ this.queue = queue;
+ this.id = NOT_SCHEDULED_ID;
+ }
+
+ @Override
+ public boolean queue() {
+ if (this.queue.hasShutdown) {
+ throw new IllegalStateException("Queue has shutdown");
+ }
+
+ synchronized (this.queue.queues) {
+ if (this.queue.hasShutdown) {
+ throw new IllegalStateException("Queue has shutdown");
+ }
+
+ final Priority priority = this.priority;
+ if (priority == Priority.COMPLETING) {
+ return false;
+ }
+
+ if (this.id != NOT_SCHEDULED_ID) {
+ return false;
+ }
+
+ this.queue.getAndAddTotalScheduledTasksVolatile(1L);
+ this.id = this.queue.taskIdGenerator++;
+ this.queue.queues[priority.priority].add(this);
+
+ this.queue.priorityChange(this, null, priority);
+
+ return true;
+ }
+ }
+
+ protected boolean trySetCompleting(final int minPriority) {
+ final Priority oldPriority = this.priority;
+ if (oldPriority != Priority.COMPLETING && oldPriority.isHigherOrEqualPriority(minPriority)) {
+ this.priority = Priority.COMPLETING;
+ if (this.id != NOT_SCHEDULED_ID) {
+ this.queue.priorityChange(this, oldPriority, Priority.COMPLETING);
+ }
+ return true;
+ }
+
+ return false;
+ }
+
+ @Override
+ public Priority getPriority() {
+ return this.priority;
+ }
+
+ @Override
+ public boolean setPriority(final Priority priority) {
+ if (!Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Invalid priority " + priority);
+ }
+ synchronized (this.queue.queues) {
+ final Priority curr = this.priority;
+
+ if (curr == Priority.COMPLETING) {
+ return false;
+ }
+
+ if (curr == priority) {
+ return true;
+ }
+
+ this.priority = priority;
+ if (this.id != NOT_SCHEDULED_ID) {
+ this.queue.queues[priority.priority].add(this);
+
+ // call priority change callback
+ this.queue.priorityChange(this, curr, priority);
+ }
+ }
+
+ return true;
+ }
+
+ @Override
+ public boolean raisePriority(final Priority priority) {
+ if (!Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Invalid priority " + priority);
+ }
+
+ synchronized (this.queue.queues) {
+ final Priority curr = this.priority;
+
+ if (curr == Priority.COMPLETING) {
+ return false;
+ }
+
+ if (curr.isHigherOrEqualPriority(priority)) {
+ return true;
+ }
+
+ this.priority = priority;
+ if (this.id != NOT_SCHEDULED_ID) {
+ this.queue.queues[priority.priority].add(this);
+
+ // call priority change callback
+ this.queue.priorityChange(this, curr, priority);
+ }
+ }
+
+ return true;
+ }
+
+ @Override
+ public boolean lowerPriority(final Priority priority) {
+ if (!Priority.isValidPriority(priority)) {
+ throw new IllegalArgumentException("Invalid priority " + priority);
+ }
+
+ synchronized (this.queue.queues) {
+ final Priority curr = this.priority;
+
+ if (curr == Priority.COMPLETING) {
+ return false;
+ }
+
+ if (curr.isLowerOrEqualPriority(priority)) {
+ return true;
+ }
+
+ this.priority = priority;
+ if (this.id != NOT_SCHEDULED_ID) {
+ this.queue.queues[priority.priority].add(this);
+
+ // call priority change callback
+ this.queue.priorityChange(this, curr, priority);
+ }
+ }
+
+ return true;
+ }
+
+ @Override
+ public boolean cancel() {
+ final long id;
+ synchronized (this.queue.queues) {
+ final Priority oldPriority = this.priority;
+ if (oldPriority == Priority.COMPLETING) {
+ return false;
+ }
+
+ this.priority = Priority.COMPLETING;
+ // call priority change callback
+ if ((id = this.id) != NOT_SCHEDULED_ID) {
+ this.queue.priorityChange(this, oldPriority, Priority.COMPLETING);
+ }
+ }
+ this.runnable = null;
+ if (id != NOT_SCHEDULED_ID) {
+ this.queue.getAndAddTotalCompletedTasksVolatile(1L);
+ }
+ return true;
+ }
+
+ protected void executeInternal() {
+ try {
+ final Runnable execute = this.runnable;
+ this.runnable = null;
+ execute.run();
+ } finally {
+ if (this.id != NOT_SCHEDULED_ID) {
+ this.queue.getAndAddTotalCompletedTasksVolatile(1L);
+ }
+ }
+ }
+
+ @Override
+ public boolean execute() {
+ synchronized (this.queue.queues) {
+ final Priority oldPriority = this.priority;
+ if (oldPriority == Priority.COMPLETING) {
+ return false;
+ }
+
+ this.priority = Priority.COMPLETING;
+ // call priority change callback
+ if (this.id != NOT_SCHEDULED_ID) {
+ this.queue.priorityChange(this, oldPriority, Priority.COMPLETING);
+ }
+ }
+
+ this.executeInternal();
+ return true;
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/function/BiLong1Function.java b/src/main/java/ca/spottedleaf/concurrentutil/function/BiLong1Function.java
new file mode 100644
index 0000000000000000000000000000000000000000..94bfd7c56ffcea7d6491e94a7804bc3bd60fe9c3
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/function/BiLong1Function.java
@@ -0,0 +1,8 @@
+package ca.spottedleaf.concurrentutil.function;
+
+@FunctionalInterface
+public interface BiLong1Function<T, R> {
+
+ public R apply(final long t1, final T t2);
+
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/function/BiLongObjectConsumer.java b/src/main/java/ca/spottedleaf/concurrentutil/function/BiLongObjectConsumer.java
new file mode 100644
index 0000000000000000000000000000000000000000..8e7eef07960a18d0593688eba55adfa1c85efadf
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/function/BiLongObjectConsumer.java
@@ -0,0 +1,8 @@
+package ca.spottedleaf.concurrentutil.function;
+
+@FunctionalInterface
+public interface BiLongObjectConsumer<V> {
+
+ public void accept(final long key, final V value);
+
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/lock/ReentrantAreaLock.java b/src/main/java/ca/spottedleaf/concurrentutil/lock/ReentrantAreaLock.java
new file mode 100644
index 0000000000000000000000000000000000000000..7ffe4379b06c03c56abbcbdee3bb720894a10702
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/lock/ReentrantAreaLock.java
@@ -0,0 +1,350 @@
+package ca.spottedleaf.concurrentutil.lock;
+
+import ca.spottedleaf.concurrentutil.collection.MultiThreadedQueue;
+import ca.spottedleaf.concurrentutil.map.ConcurrentLong2ReferenceChainedHashTable;
+import ca.spottedleaf.concurrentutil.util.IntPairUtil;
+import java.util.Objects;
+import java.util.concurrent.locks.LockSupport;
+
+public final class ReentrantAreaLock {
+
+ public final int coordinateShift;
+
+ // aggressive load factor to reduce contention
+ private final ConcurrentLong2ReferenceChainedHashTable<Node> nodes = ConcurrentLong2ReferenceChainedHashTable.createWithCapacity(128, 0.2f);
+
+ public ReentrantAreaLock(final int coordinateShift) {
+ this.coordinateShift = coordinateShift;
+ }
+
+ public boolean isHeldByCurrentThread(final int x, final int z) {
+ final Thread currThread = Thread.currentThread();
+ final int shift = this.coordinateShift;
+ final int sectionX = x >> shift;
+ final int sectionZ = z >> shift;
+
+ final long coordinate = IntPairUtil.key(sectionX, sectionZ);
+ final Node node = this.nodes.get(coordinate);
+
+ return node != null && node.thread == currThread;
+ }
+
+ public boolean isHeldByCurrentThread(final int centerX, final int centerZ, final int radius) {
+ return this.isHeldByCurrentThread(centerX - radius, centerZ - radius, centerX + radius, centerZ + radius);
+ }
+
+ public boolean isHeldByCurrentThread(final int fromX, final int fromZ, final int toX, final int toZ) {
+ if (fromX > toX || fromZ > toZ) {
+ throw new IllegalArgumentException();
+ }
+
+ final Thread currThread = Thread.currentThread();
+ final int shift = this.coordinateShift;
+ final int fromSectionX = fromX >> shift;
+ final int fromSectionZ = fromZ >> shift;
+ final int toSectionX = toX >> shift;
+ final int toSectionZ = toZ >> shift;
+
+ for (int currZ = fromSectionZ; currZ <= toSectionZ; ++currZ) {
+ for (int currX = fromSectionX; currX <= toSectionX; ++currX) {
+ final long coordinate = IntPairUtil.key(currX, currZ);
+
+ final Node node = this.nodes.get(coordinate);
+
+ if (node == null || node.thread != currThread) {
+ return false;
+ }
+ }
+ }
+
+ return true;
+ }
+
+ public Node tryLock(final int x, final int z) {
+ return this.tryLock(x, z, x, z);
+ }
+
+ public Node tryLock(final int centerX, final int centerZ, final int radius) {
+ return this.tryLock(centerX - radius, centerZ - radius, centerX + radius, centerZ + radius);
+ }
+
+ public Node tryLock(final int fromX, final int fromZ, final int toX, final int toZ) {
+ if (fromX > toX || fromZ > toZ) {
+ throw new IllegalArgumentException();
+ }
+
+ final Thread currThread = Thread.currentThread();
+ final int shift = this.coordinateShift;
+ final int fromSectionX = fromX >> shift;
+ final int fromSectionZ = fromZ >> shift;
+ final int toSectionX = toX >> shift;
+ final int toSectionZ = toZ >> shift;
+
+ final long[] areaAffected = new long[(toSectionX - fromSectionX + 1) * (toSectionZ - fromSectionZ + 1)];
+ int areaAffectedLen = 0;
+
+ final Node ret = new Node(this, areaAffected, currThread);
+
+ boolean failed = false;
+
+ // try to fast acquire area
+ for (int currZ = fromSectionZ; currZ <= toSectionZ; ++currZ) {
+ for (int currX = fromSectionX; currX <= toSectionX; ++currX) {
+ final long coordinate = IntPairUtil.key(currX, currZ);
+
+ final Node prev = this.nodes.putIfAbsent(coordinate, ret);
+
+ if (prev == null) {
+ areaAffected[areaAffectedLen++] = coordinate;
+ continue;
+ }
+
+ if (prev.thread != currThread) {
+ failed = true;
+ break;
+ }
+ }
+ }
+
+ if (!failed) {
+ return ret;
+ }
+
+ // failed, undo logic
+ if (areaAffectedLen != 0) {
+ for (int i = 0; i < areaAffectedLen; ++i) {
+ final long key = areaAffected[i];
+
+ if (this.nodes.remove(key) != ret) {
+ throw new IllegalStateException();
+ }
+ }
+
+ areaAffectedLen = 0;
+
+ // since we inserted, we need to drain waiters
+ Thread unpark;
+ while ((unpark = ret.pollOrBlockAdds()) != null) {
+ LockSupport.unpark(unpark);
+ }
+ }
+
+ return null;
+ }
+
+ public Node lock(final int x, final int z) {
+ final Thread currThread = Thread.currentThread();
+ final int shift = this.coordinateShift;
+ final int sectionX = x >> shift;
+ final int sectionZ = z >> shift;
+
+ final long coordinate = IntPairUtil.key(sectionX, sectionZ);
+ final long[] areaAffected = new long[1];
+ areaAffected[0] = coordinate;
+
+ final Node ret = new Node(this, areaAffected, currThread);
+
+ for (long failures = 0L;;) {
+ final Node park;
+
+ // try to fast acquire area
+ {
+ final Node prev = this.nodes.putIfAbsent(coordinate, ret);
+
+ if (prev == null) {
+ ret.areaAffectedLen = 1;
+ return ret;
+ } else if (prev.thread != currThread) {
+ park = prev;
+ } else {
+ // only one node we would want to acquire, and it's owned by this thread already
+ // areaAffectedLen = 0 already
+ return ret;
+ }
+ }
+
+ ++failures;
+
+ if (failures > 128L && park.add(currThread)) {
+ LockSupport.park();
+ } else {
+ // high contention, spin wait
+ if (failures < 128L) {
+ for (long i = 0; i < failures; ++i) {
+ Thread.onSpinWait();
+ }
+ failures = failures << 1;
+ } else if (failures < 1_200L) {
+ LockSupport.parkNanos(1_000L);
+ failures = failures + 1L;
+ } else { // scale 0.1ms (100us) per failure
+ Thread.yield();
+ LockSupport.parkNanos(100_000L * failures);
+ failures = failures + 1L;
+ }
+ }
+ }
+ }
+
+ public Node lock(final int centerX, final int centerZ, final int radius) {
+ return this.lock(centerX - radius, centerZ - radius, centerX + radius, centerZ + radius);
+ }
+
+ public Node lock(final int fromX, final int fromZ, final int toX, final int toZ) {
+ if (fromX > toX || fromZ > toZ) {
+ throw new IllegalArgumentException();
+ }
+
+ final Thread currThread = Thread.currentThread();
+ final int shift = this.coordinateShift;
+ final int fromSectionX = fromX >> shift;
+ final int fromSectionZ = fromZ >> shift;
+ final int toSectionX = toX >> shift;
+ final int toSectionZ = toZ >> shift;
+
+ if (((fromSectionX ^ toSectionX) | (fromSectionZ ^ toSectionZ)) == 0) {
+ return this.lock(fromX, fromZ);
+ }
+
+ final long[] areaAffected = new long[(toSectionX - fromSectionX + 1) * (toSectionZ - fromSectionZ + 1)];
+ int areaAffectedLen = 0;
+
+ final Node ret = new Node(this, areaAffected, currThread);
+
+ for (long failures = 0L;;) {
+ Node park = null;
+ boolean addedToArea = false;
+ boolean alreadyOwned = false;
+ boolean allOwned = true;
+
+ // try to fast acquire area
+ for (int currZ = fromSectionZ; currZ <= toSectionZ; ++currZ) {
+ for (int currX = fromSectionX; currX <= toSectionX; ++currX) {
+ final long coordinate = IntPairUtil.key(currX, currZ);
+
+ final Node prev = this.nodes.putIfAbsent(coordinate, ret);
+
+ if (prev == null) {
+ addedToArea = true;
+ allOwned = false;
+ areaAffected[areaAffectedLen++] = coordinate;
+ continue;
+ }
+
+ if (prev.thread != currThread) {
+ park = prev;
+ alreadyOwned = true;
+ break;
+ }
+ }
+ }
+
+ // check for failure
+ if ((park != null && addedToArea) || (park == null && alreadyOwned && !allOwned)) {
+ // failure to acquire: added and we need to block, or improper lock usage
+ for (int i = 0; i < areaAffectedLen; ++i) {
+ final long key = areaAffected[i];
+
+ if (this.nodes.remove(key) != ret) {
+ throw new IllegalStateException();
+ }
+ }
+
+ areaAffectedLen = 0;
+
+ // since we inserted, we need to drain waiters
+ Thread unpark;
+ while ((unpark = ret.pollOrBlockAdds()) != null) {
+ LockSupport.unpark(unpark);
+ }
+ }
+
+ if (park == null) {
+ if (alreadyOwned && !allOwned) {
+ throw new IllegalStateException("Improper lock usage: Should never acquire intersecting areas");
+ }
+ ret.areaAffectedLen = areaAffectedLen;
+ return ret;
+ }
+
+ // failed
+
+ ++failures;
+
+ if (failures > 128L && park.add(currThread)) {
+ LockSupport.park(park);
+ } else {
+ // high contention, spin wait
+ if (failures < 128L) {
+ for (long i = 0; i < failures; ++i) {
+ Thread.onSpinWait();
+ }
+ failures = failures << 1;
+ } else if (failures < 1_200L) {
+ LockSupport.parkNanos(1_000L);
+ failures = failures + 1L;
+ } else { // scale 0.1ms (100us) per failure
+ Thread.yield();
+ LockSupport.parkNanos(100_000L * failures);
+ failures = failures + 1L;
+ }
+ }
+
+ if (addedToArea) {
+ // try again, so we need to allow adds so that other threads can properly block on us
+ ret.allowAdds();
+ }
+ }
+ }
+
+ public void unlock(final Node node) {
+ if (node.lock != this) {
+ throw new IllegalStateException("Unlock target lock mismatch");
+ }
+
+ final long[] areaAffected = node.areaAffected;
+ final int areaAffectedLen = node.areaAffectedLen;
+
+ if (areaAffectedLen == 0) {
+ // here we are not in the node map, and so do not need to remove from the node map or unblock any waiters
+ return;
+ }
+
+ Objects.checkFromToIndex(0, areaAffectedLen, areaAffected.length);
+
+ // remove from node map; allowing other threads to lock
+ for (int i = 0; i < areaAffectedLen; ++i) {
+ final long coordinate = areaAffected[i];
+ if (this.nodes.remove(coordinate, node) != node) {
+ throw new IllegalStateException();
+ }
+ }
+
+ Thread unpark;
+ while ((unpark = node.pollOrBlockAdds()) != null) {
+ LockSupport.unpark(unpark);
+ }
+ }
+
+ public static final class Node extends MultiThreadedQueue<Thread> {
+
+ private final ReentrantAreaLock lock;
+ private final long[] areaAffected;
+ private int areaAffectedLen;
+ private final Thread thread;
+
+ private Node(final ReentrantAreaLock lock, final long[] areaAffected, final Thread thread) {
+ this.lock = lock;
+ this.areaAffected = areaAffected;
+ this.thread = thread;
+ }
+
+ @Override
+ public String toString() {
+ return "Node{" +
+ "areaAffected=" + IntPairUtil.toString(this.areaAffected, 0, this.areaAffectedLen) +
+ ", thread=" + this.thread +
+ '}';
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/map/ConcurrentLong2ReferenceChainedHashTable.java b/src/main/java/ca/spottedleaf/concurrentutil/map/ConcurrentLong2ReferenceChainedHashTable.java
new file mode 100644
index 0000000000000000000000000000000000000000..d701998b376579ec652fb94823befa3cc0bc4090
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/map/ConcurrentLong2ReferenceChainedHashTable.java
@@ -0,0 +1,1684 @@
+package ca.spottedleaf.concurrentutil.map;
+
+import ca.spottedleaf.concurrentutil.function.BiLong1Function;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import ca.spottedleaf.concurrentutil.util.HashUtil;
+import ca.spottedleaf.concurrentutil.util.IntegerUtil;
+import ca.spottedleaf.concurrentutil.util.ThrowUtil;
+import ca.spottedleaf.concurrentutil.util.Validate;
+import java.lang.invoke.VarHandle;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.PrimitiveIterator;
+import java.util.concurrent.atomic.LongAdder;
+import java.util.function.BiFunction;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.LongConsumer;
+import java.util.function.LongFunction;
+import java.util.function.Predicate;
+
+/**
+ * Concurrent hashtable implementation supporting mapping arbitrary {@code long} values onto non-null {@code Object}
+ * values with support for multiple writer and multiple reader threads.
+ *
+ * <p><h3>Happens-before relationship</h3></p>
+ * <p>
+ * As with {@link java.util.concurrent.ConcurrentMap}, there is a happens-before relationship between actions in one thread
+ * prior to writing to the map and access to the results of those actions in another thread.
+ * </p>
+ *
+ * <p><h3>Atomicity of functional methods</h3></p>
+ * <p>
+ * Functional methods are functions declared in this class which possibly perform a write (remove, replace, or modify)
+ * to an entry in this map as a result of invoking a function on an input parameter. For example, {@link #compute(long, BiLong1Function)},
+ * {@link #merge(long, Object, BiFunction)} and {@link #removeIf(long, Predicate)} are examples of functional methods.
+ * Functional methods will be performed atomically, that is, the input parameter is guaranteed to only be invoked at most
+ * once per function call. The consequence of this behavior however is that a critical lock for a bin entry is held, which
+ * means that if the input parameter invocation makes additional calls to write into this hash table that the result
+ * is undefined and deadlock-prone.
+ * </p>
+ *
+ * @param <V>
+ * @see java.util.concurrent.ConcurrentMap
+ */
+public class ConcurrentLong2ReferenceChainedHashTable<V> {
+
+ protected static final int DEFAULT_CAPACITY = 16;
+ protected static final float DEFAULT_LOAD_FACTOR = 0.75f;
+ protected static final int MAXIMUM_CAPACITY = Integer.MIN_VALUE >>> 1;
+
+ protected final LongAdder size = new LongAdder();
+ protected final float loadFactor;
+
+ protected volatile TableEntry<V>[] table;
+
+ protected static final int THRESHOLD_NO_RESIZE = -1;
+ protected static final int THRESHOLD_RESIZING = -2;
+ protected volatile int threshold;
+ protected static final VarHandle THRESHOLD_HANDLE = ConcurrentUtil.getVarHandle(ConcurrentLong2ReferenceChainedHashTable.class, "threshold", int.class);
+
+ protected final int getThresholdAcquire() {
+ return (int)THRESHOLD_HANDLE.getAcquire(this);
+ }
+
+ protected final int getThresholdVolatile() {
+ return (int)THRESHOLD_HANDLE.getVolatile(this);
+ }
+
+ protected final void setThresholdPlain(final int threshold) {
+ THRESHOLD_HANDLE.set(this, threshold);
+ }
+
+ protected final void setThresholdRelease(final int threshold) {
+ THRESHOLD_HANDLE.setRelease(this, threshold);
+ }
+
+ protected final void setThresholdVolatile(final int threshold) {
+ THRESHOLD_HANDLE.setVolatile(this, threshold);
+ }
+
+ protected final int compareExchangeThresholdVolatile(final int expect, final int update) {
+ return (int)THRESHOLD_HANDLE.compareAndExchange(this, expect, update);
+ }
+
+ public ConcurrentLong2ReferenceChainedHashTable() {
+ this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR);
+ }
+
+ protected static int getTargetThreshold(final int capacity, final float loadFactor) {
+ final double ret = (double)capacity * (double)loadFactor;
+ if (Double.isInfinite(ret) || ret >= ((double)Integer.MAX_VALUE)) {
+ return THRESHOLD_NO_RESIZE;
+ }
+
+ return (int)Math.ceil(ret);
+ }
+
+ protected static int getCapacityFor(final int capacity) {
+ if (capacity <= 0) {
+ throw new IllegalArgumentException("Invalid capacity: " + capacity);
+ }
+ if (capacity >= MAXIMUM_CAPACITY) {
+ return MAXIMUM_CAPACITY;
+ }
+ return IntegerUtil.roundCeilLog2(capacity);
+ }
+
+ protected ConcurrentLong2ReferenceChainedHashTable(final int capacity, final float loadFactor) {
+ final int tableSize = getCapacityFor(capacity);
+
+ if (loadFactor <= 0.0 || !Float.isFinite(loadFactor)) {
+ throw new IllegalArgumentException("Invalid load factor: " + loadFactor);
+ }
+
+ if (tableSize == MAXIMUM_CAPACITY) {
+ this.setThresholdPlain(THRESHOLD_NO_RESIZE);
+ } else {
+ this.setThresholdPlain(getTargetThreshold(tableSize, loadFactor));
+ }
+
+ this.loadFactor = loadFactor;
+ // noinspection unchecked
+ this.table = (TableEntry<V>[])new TableEntry[tableSize];
+ }
+
+ public static <V> ConcurrentLong2ReferenceChainedHashTable<V> createWithCapacity(final int capacity) {
+ return createWithCapacity(capacity, DEFAULT_LOAD_FACTOR);
+ }
+
+ public static <V> ConcurrentLong2ReferenceChainedHashTable<V> createWithCapacity(final int capacity, final float loadFactor) {
+ return new ConcurrentLong2ReferenceChainedHashTable<>(capacity, loadFactor);
+ }
+
+ public static <V> ConcurrentLong2ReferenceChainedHashTable<V> createWithExpected(final int expected) {
+ return createWithExpected(expected, DEFAULT_LOAD_FACTOR);
+ }
+
+ public static <V> ConcurrentLong2ReferenceChainedHashTable<V> createWithExpected(final int expected, final float loadFactor) {
+ final int capacity = (int)Math.ceil((double)expected / (double)loadFactor);
+
+ return createWithCapacity(capacity, loadFactor);
+ }
+
+ /** must be deterministic given a key */
+ protected static int getHash(final long key) {
+ return (int)HashUtil.mix(key);
+ }
+
+ /**
+ * Returns the load factor associated with this map.
+ */
+ public final float getLoadFactor() {
+ return this.loadFactor;
+ }
+
+ protected static <V> TableEntry<V> getAtIndexVolatile(final TableEntry<V>[] table, final int index) {
+ //noinspection unchecked
+ return (TableEntry<V>)TableEntry.TABLE_ENTRY_ARRAY_HANDLE.getVolatile(table, index);
+ }
+
+ protected static <V> void setAtIndexRelease(final TableEntry<V>[] table, final int index, final TableEntry<V> value) {
+ TableEntry.TABLE_ENTRY_ARRAY_HANDLE.setRelease(table, index, value);
+ }
+
+ protected static <V> void setAtIndexVolatile(final TableEntry<V>[] table, final int index, final TableEntry<V> value) {
+ TableEntry.TABLE_ENTRY_ARRAY_HANDLE.setVolatile(table, index, value);
+ }
+
+ protected static <V> TableEntry<V> compareAndExchangeAtIndexVolatile(final TableEntry<V>[] table, final int index,
+ final TableEntry<V> expect, final TableEntry<V> update) {
+ //noinspection unchecked
+ return (TableEntry<V>)TableEntry.TABLE_ENTRY_ARRAY_HANDLE.compareAndExchange(table, index, expect, update);
+ }
+
+ /**
+ * Returns the possible node associated with the key, or {@code null} if there is no such node. The node
+ * returned may have a {@code null} {@link TableEntry#value}, in which case the node is a placeholder for
+ * a compute/computeIfAbsent call. The placeholder node should not be considered mapped in order to preserve
+ * happens-before relationships between writes and reads in the map.
+ */
+ protected final TableEntry<V> getNode(final long key) {
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ for (;;) {
+ TableEntry<V> node = getAtIndexVolatile(table, hash & (table.length - 1));
+
+ if (node == null) {
+ // node == null
+ return node;
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue;
+ }
+
+ for (; node != null; node = node.getNextVolatile()) {
+ if (node.key == key) {
+ return node;
+ }
+ }
+
+ // node == null
+ return node;
+ }
+ }
+
+ /**
+ * Returns the currently mapped value associated with the specified key, or {@code null} if there is none.
+ *
+ * @param key Specified key
+ */
+ public V get(final long key) {
+ final TableEntry<V> node = this.getNode(key);
+ return node == null ? null : node.getValueVolatile();
+ }
+
+ /**
+ * Returns the currently mapped value associated with the specified key, or the specified default value if there is none.
+ *
+ * @param key Specified key
+ * @param defaultValue Specified default value
+ */
+ public V getOrDefault(final long key, final V defaultValue) {
+ final TableEntry<V> node = this.getNode(key);
+ if (node == null) {
+ return defaultValue;
+ }
+
+ final V ret = node.getValueVolatile();
+ if (ret == null) {
+ // ret == null for nodes pre-allocated to compute() and friends
+ return defaultValue;
+ }
+
+ return ret;
+ }
+
+ /**
+ * Returns whether the specified key is mapped to some value.
+ * @param key Specified key
+ */
+ public boolean containsKey(final long key) {
+ // cannot use getNode, as the node may be a placeholder for compute()
+ return this.get(key) != null;
+ }
+
+ /**
+ * Returns whether the specified value has a key mapped to it.
+ * @param value Specified value
+ * @throws NullPointerException If value is null
+ */
+ public boolean containsValue(final V value) {
+ Validate.notNull(value, "Value cannot be null");
+
+ final NodeIterator<V> iterator = new NodeIterator<>(this.table);
+
+ TableEntry<V> node;
+ while ((node = iterator.findNext()) != null) {
+ // need to use acquire here to ensure the happens-before relationship
+ if (node.getValueAcquire() == value) {
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ /**
+ * Returns the number of mappings in this map.
+ */
+ public int size() {
+ final long ret = this.size.sum();
+
+ if (ret <= 0L) {
+ return 0;
+ }
+ if (ret >= (long)Integer.MAX_VALUE) {
+ return Integer.MAX_VALUE;
+ }
+
+ return (int)ret;
+ }
+
+ /**
+ * Returns whether this map has no mappings.
+ */
+ public boolean isEmpty() {
+ return this.size.sum() <= 0L;
+ }
+
+ /**
+ * Adds count to size and checks threshold for resizing
+ */
+ protected final void addSize(final long count) {
+ this.size.add(count);
+
+ final int threshold = this.getThresholdAcquire();
+
+ if (threshold < 0L) {
+ // resizing or no resizing allowed, in either cases we do not need to do anything
+ return;
+ }
+
+ final long sum = this.size.sum();
+
+ if (sum < (long)threshold) {
+ return;
+ }
+
+ if (threshold != this.compareExchangeThresholdVolatile(threshold, THRESHOLD_RESIZING)) {
+ // some other thread resized
+ return;
+ }
+
+ // create new table
+ this.resize(sum);
+ }
+
+ /**
+ * Resizes table, only invoke for the thread which has successfully updated threshold to {@link #THRESHOLD_RESIZING}
+ * @param sum Estimate of current mapping count, must be >= old threshold
+ */
+ private void resize(final long sum) {
+ int capacity;
+
+ // add 1.0, as sum may equal threshold (in which case, sum / loadFactor = current capacity)
+ // adding 1.0 should at least raise the size by a factor of two due to usage of roundCeilLog2
+ final double targetD = ((double)sum / (double)this.loadFactor) + 1.0;
+ if (targetD >= (double)MAXIMUM_CAPACITY) {
+ capacity = MAXIMUM_CAPACITY;
+ } else {
+ capacity = (int)Math.ceil(targetD);
+ capacity = IntegerUtil.roundCeilLog2(capacity);
+ if (capacity > MAXIMUM_CAPACITY) {
+ capacity = MAXIMUM_CAPACITY;
+ }
+ }
+
+ // create new table data
+
+ final TableEntry<V>[] newTable = new TableEntry[capacity];
+ // noinspection unchecked
+ final TableEntry<V> resizeNode = new TableEntry<>(0L, (V)newTable, true);
+
+ // transfer nodes from old table
+
+ // does not need to be volatile read, just plain
+ final TableEntry<V>[] oldTable = this.table;
+
+ // when resizing, the old entries at bin i (where i = hash % oldTable.length) are assigned to
+ // bin k in the new table (where k = hash % newTable.length)
+ // since both table lengths are powers of two (specifically, newTable is a multiple of oldTable),
+ // the possible number of locations in the new table to assign any given i is newTable.length/oldTable.length
+
+ // we can build the new linked nodes for the new table by using a work array sized to newTable.length/oldTable.length
+ // which holds the _last_ entry in the chain per bin
+
+ final int capOldShift = IntegerUtil.floorLog2(oldTable.length);
+ final int capDiffShift = IntegerUtil.floorLog2(capacity) - capOldShift;
+
+ if (capDiffShift == 0) {
+ throw new IllegalStateException("Resizing to same size");
+ }
+
+ final TableEntry<V>[] work = new TableEntry[1 << capDiffShift]; // typically, capDiffShift = 1
+
+ for (int i = 0, len = oldTable.length; i < len; ++i) {
+ TableEntry<V> binNode = getAtIndexVolatile(oldTable, i);
+
+ for (;;) {
+ if (binNode == null) {
+ // just need to replace the bin node, do not need to move anything
+ if (null == (binNode = compareAndExchangeAtIndexVolatile(oldTable, i, null, resizeNode))) {
+ break;
+ } // else: binNode != null, fall through
+ }
+
+ // need write lock to block other writers
+ synchronized (binNode) {
+ if (binNode != (binNode = getAtIndexVolatile(oldTable, i))) {
+ continue;
+ }
+
+ // an important detail of resizing is that we do not need to be concerned with synchronisation on
+ // writes to the new table, as no access to any nodes on bin i on oldTable will occur until a thread
+ // sees the resizeNode
+ // specifically, as long as the resizeNode is release written there are no cases where another thread
+ // will see our writes to the new table
+
+ TableEntry<V> next = binNode.getNextPlain();
+
+ if (next == null) {
+ // simple case: do not use work array
+
+ // do not need to create new node, readers only need to see the state of the map at the
+ // beginning of a call, so any additions onto _next_ don't really matter
+ // additionally, the old node is replaced so that writers automatically forward to the new table,
+ // which resolves any issues
+ newTable[getHash(binNode.key) & (capacity - 1)] = binNode;
+ } else {
+ // reset for next usage
+ Arrays.fill(work, null);
+
+ for (TableEntry<V> curr = binNode; curr != null; curr = curr.getNextPlain()) {
+ final int newTableIdx = getHash(curr.key) & (capacity - 1);
+ final int workIdx = newTableIdx >>> capOldShift;
+
+ final TableEntry<V> replace = new TableEntry<>(curr.key, curr.getValuePlain());
+
+ final TableEntry<V> workNode = work[workIdx];
+ work[workIdx] = replace;
+
+ if (workNode == null) {
+ newTable[newTableIdx] = replace;
+ continue;
+ } else {
+ workNode.setNextPlain(replace);
+ continue;
+ }
+ }
+ }
+
+ setAtIndexRelease(oldTable, i, resizeNode);
+ break;
+ }
+ }
+ }
+
+ // calculate new threshold
+ final int newThreshold;
+ if (capacity == MAXIMUM_CAPACITY) {
+ newThreshold = THRESHOLD_NO_RESIZE;
+ } else {
+ newThreshold = getTargetThreshold(capacity, loadFactor);
+ }
+
+ this.table = newTable;
+ // finish resize operation by releasing hold on threshold
+ this.setThresholdVolatile(newThreshold);
+ }
+
+ /**
+ * Subtracts count from size
+ */
+ protected final void subSize(final long count) {
+ this.size.add(-count);
+ }
+
+ /**
+ * Atomically updates the value associated with {@code key} to {@code value}, or inserts a new mapping with {@code key}
+ * mapped to {@code value}.
+ * @param key Specified key
+ * @param value Specified value
+ * @throws NullPointerException If value is null
+ * @return Old value previously associated with key, or {@code null} if none.
+ */
+ public V put(final long key, final V value) {
+ Validate.notNull(value, "Value may not be null");
+
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ if (null == (node = compareAndExchangeAtIndexVolatile(table, index, null, new TableEntry<>(key, value)))) {
+ // successfully inserted
+ this.addSize(1L);
+ return null;
+ } // else: node != null, fall through
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+ // plain reads are fine during synchronised access, as we are the only writer
+ TableEntry<V> prev = null;
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ final V ret = node.getValuePlain();
+ node.setValueVolatile(value);
+ return ret;
+ }
+ }
+
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ prev.setNextRelease(new TableEntry<>(key, value));
+ }
+
+ this.addSize(1L);
+ return null;
+ }
+ }
+ }
+
+ /**
+ * Atomically inserts a new mapping with {@code key} mapped to {@code value} if and only if {@code key} is not
+ * currently mapped to some value.
+ * @param key Specified key
+ * @param value Specified value
+ * @throws NullPointerException If value is null
+ * @return Value currently associated with key, or {@code null} if none and {@code value} was associated.
+ */
+ public V putIfAbsent(final long key, final V value) {
+ Validate.notNull(value, "Value may not be null");
+
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ if (null == (node = compareAndExchangeAtIndexVolatile(table, index, null, new TableEntry<>(key, value)))) {
+ // successfully inserted
+ this.addSize(1L);
+ return null;
+ } // else: node != null, fall through
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ // optimise ifAbsent calls: check if first node is key before attempting lock acquire
+ if (node.key == key) {
+ final V ret = node.getValueVolatile();
+ if (ret != null) {
+ return ret;
+ } // else: fall back to lock to read the node
+ }
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+ // plain reads are fine during synchronised access, as we are the only writer
+ TableEntry<V> prev = null;
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ return node.getValuePlain();
+ }
+ }
+
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ prev.setNextRelease(new TableEntry<>(key, value));
+ }
+
+ this.addSize(1L);
+ return null;
+ }
+ }
+ }
+
+ /**
+ * Atomically updates the value associated with {@code key} to {@code value}, or does nothing if {@code key} is not
+ * associated with a value.
+ * @param key Specified key
+ * @param value Specified value
+ * @throws NullPointerException If value is null
+ * @return Old value previously associated with key, or {@code null} if none.
+ */
+ public V replace(final long key, final V value) {
+ Validate.notNull(value, "Value may not be null");
+
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ return null;
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+
+ // plain reads are fine during synchronised access, as we are the only writer
+ for (; node != null; node = node.getNextPlain()) {
+ if (node.key == key) {
+ final V ret = node.getValuePlain();
+ node.setValueVolatile(value);
+ return ret;
+ }
+ }
+ }
+
+ return null;
+ }
+ }
+ }
+
+ /**
+ * Atomically updates the value associated with {@code key} to {@code update} if the currently associated
+ * value is reference equal to {@code expect}, otherwise does nothing.
+ * @param key Specified key
+ * @param expect Expected value to check current mapped value with
+ * @param update Update value to replace mapped value with
+ * @throws NullPointerException If value is null
+ * @return If the currently mapped value is not reference equal to {@code expect}, then returns the currently mapped
+ * value. If the key is not mapped to any value, then returns {@code null}. If neither of the two cases are
+ * true, then returns {@code expect}.
+ */
+ public V replace(final long key, final V expect, final V update) {
+ Validate.notNull(expect, "Expect may not be null");
+ Validate.notNull(update, "Update may not be null");
+
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ return null;
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+
+ // plain reads are fine during synchronised access, as we are the only writer
+ for (; node != null; node = node.getNextPlain()) {
+ if (node.key == key) {
+ final V ret = node.getValuePlain();
+
+ if (ret != expect) {
+ return ret;
+ }
+
+ node.setValueVolatile(update);
+ return ret;
+ }
+ }
+ }
+
+ return null;
+ }
+ }
+ }
+
+ /**
+ * Atomically removes the mapping for the specified key and returns the value it was associated with. If the key
+ * is not mapped to a value, then does nothing and returns {@code null}.
+ * @param key Specified key
+ * @return Old value previously associated with key, or {@code null} if none.
+ */
+ public V remove(final long key) {
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ return null;
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ boolean removed = false;
+ V ret = null;
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+
+ TableEntry<V> prev = null;
+
+ // plain reads are fine during synchronised access, as we are the only writer
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ ret = node.getValuePlain();
+ removed = true;
+
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ if (prev == null) {
+ setAtIndexRelease(table, index, node.getNextPlain());
+ } else {
+ prev.setNextRelease(node.getNextPlain());
+ }
+
+ break;
+ }
+ }
+ }
+
+ if (removed) {
+ this.subSize(1L);
+ }
+
+ return ret;
+ }
+ }
+ }
+
+ /**
+ * Atomically removes the mapping for the specified key if it is mapped to {@code expect} and returns {@code expect}. If the key
+ * is not mapped to a value, then does nothing and returns {@code null}. If the key is mapped to a value that is not reference
+ * equal to {@code expect}, then returns that value.
+ * @param key Specified key
+ * @param expect Specified expected value
+ * @return The specified expected value if the key was mapped to {@code expect}. If
+ * the key is not mapped to any value, then returns {@code null}. If neither of those cases are true,
+ * then returns the current (non-null) mapped value for key.
+ */
+ public V remove(final long key, final V expect) {
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ return null;
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ boolean removed = false;
+ V ret = null;
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+
+ TableEntry<V> prev = null;
+
+ // plain reads are fine during synchronised access, as we are the only writer
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ ret = node.getValuePlain();
+ if (ret == expect) {
+ removed = true;
+
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ if (prev == null) {
+ setAtIndexRelease(table, index, node.getNextPlain());
+ } else {
+ prev.setNextRelease(node.getNextPlain());
+ }
+ }
+ break;
+ }
+ }
+ }
+
+ if (removed) {
+ this.subSize(1L);
+ }
+
+ return ret;
+ }
+ }
+ }
+
+ /**
+ * Atomically removes the mapping for the specified key the predicate returns true for its currently mapped value. If the key
+ * is not mapped to a value, then does nothing and returns {@code null}.
+ *
+ * <p>
+ * This function is a "functional methods" as defined by {@link ConcurrentLong2ReferenceChainedHashTable}.
+ * </p>
+ *
+ * @param key Specified key
+ * @param predicate Specified predicate
+ * @throws NullPointerException If predicate is null
+ * @return The specified expected value if the key was mapped to {@code expect}. If
+ * the key is not mapped to any value, then returns {@code null}. If neither of those cases are true,
+ * then returns the current (non-null) mapped value for key.
+ */
+ public V removeIf(final long key, final Predicate<? super V> predicate) {
+ Validate.notNull(predicate, "Predicate may not be null");
+
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ return null;
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ boolean removed = false;
+ V ret = null;
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+
+ TableEntry<V> prev = null;
+
+ // plain reads are fine during synchronised access, as we are the only writer
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ ret = node.getValuePlain();
+ if (predicate.test(ret)) {
+ removed = true;
+
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ if (prev == null) {
+ setAtIndexRelease(table, index, node.getNextPlain());
+ } else {
+ prev.setNextRelease(node.getNextPlain());
+ }
+ }
+ break;
+ }
+ }
+ }
+
+ if (removed) {
+ this.subSize(1L);
+ }
+
+ return ret;
+ }
+ }
+ }
+
+ /**
+ * See {@link java.util.concurrent.ConcurrentMap#compute(Object, BiFunction)}
+ * <p>
+ * This function is a "functional methods" as defined by {@link ConcurrentLong2ReferenceChainedHashTable}.
+ * </p>
+ */
+ public V compute(final long key, final BiLong1Function<? super V, ? extends V> function) {
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ V ret = null;
+ if (node == null) {
+ final TableEntry<V> insert = new TableEntry<>(key, null);
+
+ boolean added = false;
+
+ synchronized (insert) {
+ if (null == (node = compareAndExchangeAtIndexVolatile(table, index, null, insert))) {
+ try {
+ ret = function.apply(key, null);
+ } catch (final Throwable throwable) {
+ setAtIndexVolatile(table, index, null);
+ ThrowUtil.throwUnchecked(throwable);
+ // unreachable
+ return null;
+ }
+
+ if (ret == null) {
+ setAtIndexVolatile(table, index, null);
+ return ret;
+ } else {
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ insert.setValueRelease(ret);
+ added = true;
+ }
+ } // else: node != null, fall through
+ }
+
+ if (added) {
+ this.addSize(1L);
+ return ret;
+ }
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ boolean removed = false;
+ boolean added = false;
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+ // plain reads are fine during synchronised access, as we are the only writer
+ TableEntry<V> prev = null;
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ final V old = node.getValuePlain();
+
+ final V computed = function.apply(key, old);
+
+ if (computed != null) {
+ node.setValueVolatile(computed);
+ return computed;
+ }
+
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ if (prev == null) {
+ setAtIndexRelease(table, index, node.getNextPlain());
+ } else {
+ prev.setNextRelease(node.getNextPlain());
+ }
+
+ removed = true;
+ break;
+ }
+ }
+
+ if (!removed) {
+ final V computed = function.apply(key, null);
+ if (computed != null) {
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ prev.setNextRelease(new TableEntry<>(key, computed));
+ ret = computed;
+ added = true;
+ }
+ }
+ }
+
+ if (removed) {
+ this.subSize(1L);
+ }
+ if (added) {
+ this.addSize(1L);
+ }
+
+ return ret;
+ }
+ }
+ }
+
+ /**
+ * See {@link java.util.concurrent.ConcurrentMap#computeIfAbsent(Object, Function)}
+ * <p>
+ * This function is a "functional methods" as defined by {@link ConcurrentLong2ReferenceChainedHashTable}.
+ * </p>
+ */
+ public V computeIfAbsent(final long key, final LongFunction<? extends V> function) {
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ V ret = null;
+ if (node == null) {
+ final TableEntry<V> insert = new TableEntry<>(key, null);
+
+ boolean added = false;
+
+ synchronized (insert) {
+ if (null == (node = compareAndExchangeAtIndexVolatile(table, index, null, insert))) {
+ try {
+ ret = function.apply(key);
+ } catch (final Throwable throwable) {
+ setAtIndexVolatile(table, index, null);
+ ThrowUtil.throwUnchecked(throwable);
+ // unreachable
+ return null;
+ }
+
+ if (ret == null) {
+ setAtIndexVolatile(table, index, null);
+ return null;
+ } else {
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ insert.setValueRelease(ret);
+ added = true;
+ }
+ } // else: node != null, fall through
+ }
+
+ if (added) {
+ this.addSize(1L);
+ return ret;
+ }
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ // optimise ifAbsent calls: check if first node is key before attempting lock acquire
+ if (node.key == key) {
+ ret = node.getValueVolatile();
+ if (ret != null) {
+ return ret;
+ } // else: fall back to lock to read the node
+ }
+
+ boolean added = false;
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+ // plain reads are fine during synchronised access, as we are the only writer
+ TableEntry<V> prev = null;
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ ret = node.getValuePlain();
+ return ret;
+ }
+ }
+
+ final V computed = function.apply(key);
+ if (computed != null) {
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ prev.setNextRelease(new TableEntry<>(key, computed));
+ ret = computed;
+ added = true;
+ }
+ }
+
+ if (added) {
+ this.addSize(1L);
+ }
+
+ return ret;
+ }
+ }
+ }
+
+ /**
+ * See {@link java.util.concurrent.ConcurrentMap#computeIfPresent(Object, BiFunction)}
+ * <p>
+ * This function is a "functional methods" as defined by {@link ConcurrentLong2ReferenceChainedHashTable}.
+ * </p>
+ */
+ public V computeIfPresent(final long key, final BiLong1Function<? super V, ? extends V> function) {
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ return null;
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ boolean removed = false;
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+ // plain reads are fine during synchronised access, as we are the only writer
+ TableEntry<V> prev = null;
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ final V old = node.getValuePlain();
+
+ final V computed = function.apply(key, old);
+
+ if (computed != null) {
+ node.setValueVolatile(computed);
+ return computed;
+ }
+
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ if (prev == null) {
+ setAtIndexRelease(table, index, node.getNextPlain());
+ } else {
+ prev.setNextRelease(node.getNextPlain());
+ }
+
+ removed = true;
+ break;
+ }
+ }
+ }
+
+ if (removed) {
+ this.subSize(1L);
+ }
+
+ return null;
+ }
+ }
+ }
+
+ /**
+ * See {@link java.util.concurrent.ConcurrentMap#merge(Object, Object, BiFunction)}
+ * <p>
+ * This function is a "functional methods" as defined by {@link ConcurrentLong2ReferenceChainedHashTable}.
+ * </p>
+ */
+ public V merge(final long key, final V def, final BiFunction<? super V, ? super V, ? extends V> function) {
+ Validate.notNull(def, "Default value may not be null");
+
+ final int hash = getHash(key);
+
+ TableEntry<V>[] table = this.table;
+ table_loop:
+ for (;;) {
+ final int index = hash & (table.length - 1);
+
+ TableEntry<V> node = getAtIndexVolatile(table, index);
+ node_loop:
+ for (;;) {
+ if (node == null) {
+ if (null == (node = compareAndExchangeAtIndexVolatile(table, index, null, new TableEntry<>(key, def)))) {
+ // successfully inserted
+ this.addSize(1L);
+ return def;
+ } // else: node != null, fall through
+ }
+
+ if (node.resize) {
+ table = (TableEntry<V>[])node.getValuePlain();
+ continue table_loop;
+ }
+
+ boolean removed = false;
+ boolean added = false;
+ V ret = null;
+
+ synchronized (node) {
+ if (node != (node = getAtIndexVolatile(table, index))) {
+ continue node_loop;
+ }
+ // plain reads are fine during synchronised access, as we are the only writer
+ TableEntry<V> prev = null;
+ for (; node != null; prev = node, node = node.getNextPlain()) {
+ if (node.key == key) {
+ final V old = node.getValuePlain();
+
+ final V computed = function.apply(old, def);
+
+ if (computed != null) {
+ node.setValueVolatile(computed);
+ return computed;
+ }
+
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ if (prev == null) {
+ setAtIndexRelease(table, index, node.getNextPlain());
+ } else {
+ prev.setNextRelease(node.getNextPlain());
+ }
+
+ removed = true;
+ break;
+ }
+ }
+
+ if (!removed) {
+ // volatile ordering ensured by addSize(), but we need release here
+ // to ensure proper ordering with reads and other writes
+ prev.setNextRelease(new TableEntry<>(key, def));
+ ret = def;
+ added = true;
+ }
+ }
+
+ if (removed) {
+ this.subSize(1L);
+ }
+ if (added) {
+ this.addSize(1L);
+ }
+
+ return ret;
+ }
+ }
+ }
+
+ /**
+ * Removes at least all entries currently mapped at the beginning of this call. May not remove entries added during
+ * this call. As a result, only if this map is not modified during the call, that all entries will be removed by
+ * the end of the call.
+ *
+ * <p>
+ * This function is not atomic.
+ * </p>
+ */
+ public void clear() {
+ // it is possible to optimise this to directly interact with the table,
+ // but we do need to be careful when interacting with resized tables,
+ // and the NodeIterator already does this logic
+ final NodeIterator<V> nodeIterator = new NodeIterator<>(this.table);
+
+ TableEntry<V> node;
+ while ((node = nodeIterator.findNext()) != null) {
+ this.remove(node.key);
+ }
+ }
+
+ /**
+ * Returns an iterator over the entries in this map. The iterator is only guaranteed to see entries that were
+ * added before the beginning of this call, but it may see entries added during.
+ */
+ public Iterator<TableEntry<V>> entryIterator() {
+ return new EntryIterator<>(this);
+ }
+
+ /**
+ * Returns an iterator over the keys in this map. The iterator is only guaranteed to see keys that were
+ * added before the beginning of this call, but it may see keys added during.
+ */
+ public PrimitiveIterator.OfLong keyIterator() {
+ return new KeyIterator<>(this);
+ }
+
+ /**
+ * Returns an iterator over the values in this map. The iterator is only guaranteed to see values that were
+ * added before the beginning of this call, but it may see values added during.
+ */
+ public Iterator<V> valueIterator() {
+ return new ValueIterator<>(this);
+ }
+
+ protected static final class EntryIterator<V> extends BaseIteratorImpl<V, TableEntry<V>> {
+
+ protected EntryIterator(final ConcurrentLong2ReferenceChainedHashTable<V> map) {
+ super(map);
+ }
+
+ @Override
+ public TableEntry<V> next() throws NoSuchElementException {
+ return this.nextNode();
+ }
+
+ @Override
+ public void forEachRemaining(final Consumer<? super TableEntry<V>> action) {
+ Validate.notNull(action, "Action may not be null");
+ while (this.hasNext()) {
+ action.accept(this.next());
+ }
+ }
+ }
+
+ protected static final class KeyIterator<V> extends BaseIteratorImpl<V, Long> implements PrimitiveIterator.OfLong {
+
+ protected KeyIterator(final ConcurrentLong2ReferenceChainedHashTable<V> map) {
+ super(map);
+ }
+
+ @Override
+ public Long next() throws NoSuchElementException {
+ return Long.valueOf(this.nextNode().key);
+ }
+
+ @Override
+ public long nextLong() {
+ return this.nextNode().key;
+ }
+
+ @Override
+ public void forEachRemaining(final Consumer<? super Long> action) {
+ Validate.notNull(action, "Action may not be null");
+
+ if (action instanceof LongConsumer longConsumer) {
+ this.forEachRemaining(longConsumer);
+ return;
+ }
+
+ while (this.hasNext()) {
+ action.accept(this.next());
+ }
+ }
+
+ @Override
+ public void forEachRemaining(final LongConsumer action) {
+ Validate.notNull(action, "Action may not be null");
+ while (this.hasNext()) {
+ action.accept(this.nextLong());
+ }
+ }
+ }
+
+ protected static final class ValueIterator<V> extends BaseIteratorImpl<V, V> {
+
+ protected ValueIterator(final ConcurrentLong2ReferenceChainedHashTable<V> map) {
+ super(map);
+ }
+
+ @Override
+ public V next() throws NoSuchElementException {
+ return this.nextNode().getValueVolatile();
+ }
+
+ @Override
+ public void forEachRemaining(final Consumer<? super V> action) {
+ Validate.notNull(action, "Action may not be null");
+ while (this.hasNext()) {
+ action.accept(this.next());
+ }
+ }
+ }
+
+ protected static abstract class BaseIteratorImpl<V, T> extends NodeIterator<V> implements Iterator<T> {
+
+ protected final ConcurrentLong2ReferenceChainedHashTable<V> map;
+ protected TableEntry<V> lastReturned;
+ protected TableEntry<V> nextToReturn;
+
+ protected BaseIteratorImpl(final ConcurrentLong2ReferenceChainedHashTable<V> map) {
+ super(map.table);
+ this.map = map;
+ }
+
+ @Override
+ public final boolean hasNext() {
+ if (this.nextToReturn != null) {
+ return true;
+ }
+
+ return (this.nextToReturn = this.findNext()) != null;
+ }
+
+ protected final TableEntry<V> nextNode() throws NoSuchElementException {
+ TableEntry<V> ret = this.nextToReturn;
+ if (ret != null) {
+ this.lastReturned = ret;
+ this.nextToReturn = null;
+ return ret;
+ }
+ ret = this.findNext();
+ if (ret != null) {
+ this.lastReturned = ret;
+ return ret;
+ }
+ throw new NoSuchElementException();
+ }
+
+ @Override
+ public final void remove() {
+ final TableEntry<V> lastReturned = this.nextToReturn;
+ if (lastReturned == null) {
+ throw new NoSuchElementException();
+ }
+ this.lastReturned = null;
+ this.map.remove(lastReturned.key);
+ }
+
+ @Override
+ public abstract T next() throws NoSuchElementException;
+
+ // overwritten by subclasses to avoid indirection on hasNext() and next()
+ @Override
+ public abstract void forEachRemaining(final Consumer<? super T> action);
+ }
+
+ protected static class NodeIterator<V> {
+
+ protected TableEntry<V>[] currentTable;
+ protected ResizeChain<V> resizeChain;
+ protected TableEntry<V> last;
+ protected int nextBin;
+ protected int increment;
+
+ protected NodeIterator(final TableEntry<V>[] baseTable) {
+ this.currentTable = baseTable;
+ this.increment = 1;
+ }
+
+ private TableEntry<V>[] pullResizeChain(final int index) {
+ final ResizeChain<V> resizeChain = this.resizeChain;
+ if (resizeChain == null) {
+ this.currentTable = null;
+ return null;
+ }
+
+ final ResizeChain<V> prevChain = resizeChain.prev;
+ this.resizeChain = prevChain;
+ if (prevChain == null) {
+ this.currentTable = null;
+ return null;
+ }
+
+ final TableEntry<V>[] newTable = prevChain.table;
+
+ // we recover the original index by modding by the new table length, as the increments applied to the index
+ // are a multiple of the new table's length
+ int newIdx = index & (newTable.length - 1);
+
+ // the increment is always the previous table's length
+ final ResizeChain<V> nextPrevChain = prevChain.prev;
+ final int increment;
+ if (nextPrevChain == null) {
+ increment = 1;
+ } else {
+ increment = nextPrevChain.table.length;
+ }
+
+ // done with the upper table, so we can skip the resize node
+ newIdx += increment;
+
+ this.increment = increment;
+ this.nextBin = newIdx;
+ this.currentTable = newTable;
+
+ return newTable;
+ }
+
+ private TableEntry<V>[] pushResizeChain(final TableEntry<V>[] table, final TableEntry<V> entry) {
+ final ResizeChain<V> chain = this.resizeChain;
+
+ if (chain == null) {
+ final TableEntry<V>[] nextTable = (TableEntry<V>[])entry.getValuePlain();
+
+ final ResizeChain<V> oldChain = new ResizeChain<>(table, null, null);
+ final ResizeChain<V> currChain = new ResizeChain<>(nextTable, oldChain, null);
+ oldChain.next = currChain;
+
+ this.increment = table.length;
+ this.resizeChain = currChain;
+ this.currentTable = nextTable;
+
+ return nextTable;
+ } else {
+ ResizeChain<V> currChain = chain.next;
+ if (currChain == null) {
+ final TableEntry<V>[] ret = (TableEntry<V>[])entry.getValuePlain();
+ currChain = new ResizeChain<>(ret, chain, null);
+ chain.next = currChain;
+
+ this.increment = table.length;
+ this.resizeChain = currChain;
+ this.currentTable = ret;
+
+ return ret;
+ } else {
+ this.increment = table.length;
+ this.resizeChain = currChain;
+ return this.currentTable = currChain.table;
+ }
+ }
+ }
+
+ protected final TableEntry<V> findNext() {
+ for (;;) {
+ final TableEntry<V> last = this.last;
+ if (last != null) {
+ final TableEntry<V> next = last.getNextVolatile();
+ if (next != null) {
+ this.last = next;
+ if (next.getValuePlain() == null) {
+ // compute() node not yet available
+ continue;
+ }
+ return next;
+ }
+ }
+
+ TableEntry<V>[] table = this.currentTable;
+
+ if (table == null) {
+ return null;
+ }
+
+ int idx = this.nextBin;
+ int increment = this.increment;
+ for (;;) {
+ if (idx >= table.length) {
+ table = this.pullResizeChain(idx);
+ idx = this.nextBin;
+ increment = this.increment;
+ if (table != null) {
+ continue;
+ } else {
+ this.last = null;
+ return null;
+ }
+ }
+
+ final TableEntry<V> entry = getAtIndexVolatile(table, idx);
+ if (entry == null) {
+ idx += increment;
+ continue;
+ }
+
+ if (entry.resize) {
+ // push onto resize chain
+ table = this.pushResizeChain(table, entry);
+ increment = this.increment;
+ continue;
+ }
+
+ this.last = entry;
+ this.nextBin = idx + increment;
+ if (entry.getValuePlain() != null) {
+ return entry;
+ } else {
+ // compute() node not yet available
+ break;
+ }
+ }
+ }
+ }
+
+ protected static final class ResizeChain<V> {
+
+ protected final TableEntry<V>[] table;
+ protected final ResizeChain<V> prev;
+ protected ResizeChain<V> next;
+
+ protected ResizeChain(final TableEntry<V>[] table, final ResizeChain<V> prev, final ResizeChain<V> next) {
+ this.table = table;
+ this.prev = prev;
+ this.next = next;
+ }
+ }
+ }
+
+ public static final class TableEntry<V> {
+
+ protected static final VarHandle TABLE_ENTRY_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(TableEntry[].class);
+
+ protected final boolean resize;
+
+ protected final long key;
+
+ protected volatile V value;
+ protected static final VarHandle VALUE_HANDLE = ConcurrentUtil.getVarHandle(TableEntry.class, "value", Object.class);
+
+ protected final V getValuePlain() {
+ //noinspection unchecked
+ return (V)VALUE_HANDLE.get(this);
+ }
+
+ protected final V getValueAcquire() {
+ //noinspection unchecked
+ return (V)VALUE_HANDLE.getAcquire(this);
+ }
+
+ protected final V getValueVolatile() {
+ //noinspection unchecked
+ return (V)VALUE_HANDLE.getVolatile(this);
+ }
+
+ protected final void setValuePlain(final V value) {
+ VALUE_HANDLE.set(this, (Object)value);
+ }
+
+ protected final void setValueRelease(final V value) {
+ VALUE_HANDLE.setRelease(this, (Object)value);
+ }
+
+ protected final void setValueVolatile(final V value) {
+ VALUE_HANDLE.setVolatile(this, (Object)value);
+ }
+
+ protected volatile TableEntry<V> next;
+ protected static final VarHandle NEXT_HANDLE = ConcurrentUtil.getVarHandle(TableEntry.class, "next", TableEntry.class);
+
+ protected final TableEntry<V> getNextPlain() {
+ //noinspection unchecked
+ return (TableEntry<V>)NEXT_HANDLE.get(this);
+ }
+
+ protected final TableEntry<V> getNextVolatile() {
+ //noinspection unchecked
+ return (TableEntry<V>)NEXT_HANDLE.getVolatile(this);
+ }
+
+ protected final void setNextPlain(final TableEntry<V> next) {
+ NEXT_HANDLE.set(this, next);
+ }
+
+ protected final void setNextRelease(final TableEntry<V> next) {
+ NEXT_HANDLE.setRelease(this, next);
+ }
+
+ protected final void setNextVolatile(final TableEntry<V> next) {
+ NEXT_HANDLE.setVolatile(this, next);
+ }
+
+ public TableEntry(final long key, final V value) {
+ this.resize = false;
+ this.key = key;
+ this.setValuePlain(value);
+ }
+
+ public TableEntry(final long key, final V value, final boolean resize) {
+ this.resize = resize;
+ this.key = key;
+ this.setValuePlain(value);
+ }
+
+ public long getKey() {
+ return this.key;
+ }
+
+ public V getValue() {
+ return this.getValueVolatile();
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/map/SWMRHashTable.java b/src/main/java/ca/spottedleaf/concurrentutil/map/SWMRHashTable.java
new file mode 100644
index 0000000000000000000000000000000000000000..83965350d292ccf42a34520d84dcda3f88146cff
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/map/SWMRHashTable.java
@@ -0,0 +1,1656 @@
+package ca.spottedleaf.concurrentutil.map;
+
+import ca.spottedleaf.concurrentutil.util.CollectionUtil;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import ca.spottedleaf.concurrentutil.util.HashUtil;
+import ca.spottedleaf.concurrentutil.util.IntegerUtil;
+import ca.spottedleaf.concurrentutil.util.Validate;
+import java.lang.invoke.VarHandle;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.function.BiConsumer;
+import java.util.function.BiFunction;
+import java.util.function.BiPredicate;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.IntFunction;
+import java.util.function.Predicate;
+
+/**
+ * <p>
+ * Note: Not really tested, use at your own risk.
+ * </p>
+ * This map is safe for reading from multiple threads, however it is only safe to write from a single thread.
+ * {@code null} keys or values are not permitted. Writes to values in this map are guaranteed to be ordered by release semantics,
+ * however immediate visibility to other threads is not guaranteed. However, writes are guaranteed to be made visible eventually.
+ * Reads are ordered by acquire semantics.
+ * <p>
+ * Iterators cannot be modified concurrently, and its backing map cannot be modified concurrently. There is no
+ * fast-fail attempt made by iterators, thus modifying the iterator's backing map while iterating will have undefined
+ * behaviour.
+ * </p>
+ * <p>
+ * Subclasses should override {@link #clone()} to return correct instances of this class.
+ * </p>
+ * @param <K> {@inheritDoc}
+ * @param <V> {@inheritDoc}
+ */
+public class SWMRHashTable<K, V> implements Map<K, V>, Iterable<Map.Entry<K, V>> {
+
+ protected int size;
+
+ protected TableEntry<K, V>[] table;
+
+ protected final float loadFactor;
+
+ protected static final VarHandle SIZE_HANDLE = ConcurrentUtil.getVarHandle(SWMRHashTable.class, "size", int.class);
+ protected static final VarHandle TABLE_HANDLE = ConcurrentUtil.getVarHandle(SWMRHashTable.class, "table", TableEntry[].class);
+
+ /* size */
+
+ protected final int getSizePlain() {
+ return (int)SIZE_HANDLE.get(this);
+ }
+
+ protected final int getSizeOpaque() {
+ return (int)SIZE_HANDLE.getOpaque(this);
+ }
+
+ protected final int getSizeAcquire() {
+ return (int)SIZE_HANDLE.getAcquire(this);
+ }
+
+ protected final void setSizePlain(final int value) {
+ SIZE_HANDLE.set(this, value);
+ }
+
+ protected final void setSizeOpaque(final int value) {
+ SIZE_HANDLE.setOpaque(this, value);
+ }
+
+ protected final void setSizeRelease(final int value) {
+ SIZE_HANDLE.setRelease(this, value);
+ }
+
+ /* table */
+
+ protected final TableEntry<K, V>[] getTablePlain() {
+ //noinspection unchecked
+ return (TableEntry<K, V>[])TABLE_HANDLE.get(this);
+ }
+
+ protected final TableEntry<K, V>[] getTableAcquire() {
+ //noinspection unchecked
+ return (TableEntry<K, V>[])TABLE_HANDLE.getAcquire(this);
+ }
+
+ protected final void setTablePlain(final TableEntry<K, V>[] table) {
+ TABLE_HANDLE.set(this, table);
+ }
+
+ protected final void setTableRelease(final TableEntry<K, V>[] table) {
+ TABLE_HANDLE.setRelease(this, table);
+ }
+
+ protected static final int DEFAULT_CAPACITY = 16;
+ protected static final float DEFAULT_LOAD_FACTOR = 0.75f;
+ protected static final int MAXIMUM_CAPACITY = Integer.MIN_VALUE >>> 1;
+
+ /**
+ * Constructs this map with a capacity of {@code 16} and load factor of {@code 0.75f}.
+ */
+ public SWMRHashTable() {
+ this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR);
+ }
+
+ /**
+ * Constructs this map with the specified capacity and load factor of {@code 0.75f}.
+ * @param capacity specified initial capacity, > 0
+ */
+ public SWMRHashTable(final int capacity) {
+ this(capacity, DEFAULT_LOAD_FACTOR);
+ }
+
+ /**
+ * Constructs this map with the specified capacity and load factor.
+ * @param capacity specified capacity, > 0
+ * @param loadFactor specified load factor, > 0 && finite
+ */
+ public SWMRHashTable(final int capacity, final float loadFactor) {
+ final int tableSize = getCapacityFor(capacity);
+
+ if (loadFactor <= 0.0 || !Float.isFinite(loadFactor)) {
+ throw new IllegalArgumentException("Invalid load factor: " + loadFactor);
+ }
+
+ //noinspection unchecked
+ final TableEntry<K, V>[] table = new TableEntry[tableSize];
+ this.setTablePlain(table);
+
+ if (tableSize == MAXIMUM_CAPACITY) {
+ this.threshold = -1;
+ } else {
+ this.threshold = getTargetCapacity(tableSize, loadFactor);
+ }
+
+ this.loadFactor = loadFactor;
+ }
+
+ /**
+ * Constructs this map with a capacity of {@code 16} or the specified map's size, whichever is larger, and
+ * with a load factor of {@code 0.75f}.
+ * All of the specified map's entries are copied into this map.
+ * @param other The specified map.
+ */
+ public SWMRHashTable(final Map<K, V> other) {
+ this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, other);
+ }
+
+ /**
+ * Constructs this map with a minimum capacity of the specified capacity or the specified map's size, whichever is larger, and
+ * with a load factor of {@code 0.75f}.
+ * All of the specified map's entries are copied into this map.
+ * @param capacity specified capacity, > 0
+ * @param other The specified map.
+ */
+ public SWMRHashTable(final int capacity, final Map<K, V> other) {
+ this(capacity, DEFAULT_LOAD_FACTOR, other);
+ }
+
+ /**
+ * Constructs this map with a min capacity of the specified capacity or the specified map's size, whichever is larger, and
+ * with the specified load factor.
+ * All of the specified map's entries are copied into this map.
+ * @param capacity specified capacity, > 0
+ * @param loadFactor specified load factor, > 0 && finite
+ * @param other The specified map.
+ */
+ public SWMRHashTable(final int capacity, final float loadFactor, final Map<K, V> other) {
+ this(Math.max(Validate.notNull(other, "Null map").size(), capacity), loadFactor);
+ this.putAll(other);
+ }
+
+ protected static <K, V> TableEntry<K, V> getAtIndexOpaque(final TableEntry<K, V>[] table, final int index) {
+ // noinspection unchecked
+ return (TableEntry<K, V>)TableEntry.TABLE_ENTRY_ARRAY_HANDLE.getOpaque(table, index);
+ }
+
+ protected static <K, V> void setAtIndexRelease(final TableEntry<K, V>[] table, final int index, final TableEntry<K, V> value) {
+ TableEntry.TABLE_ENTRY_ARRAY_HANDLE.setRelease(table, index, value);
+ }
+
+ public final float getLoadFactor() {
+ return this.loadFactor;
+ }
+
+ protected static int getCapacityFor(final int capacity) {
+ if (capacity <= 0) {
+ throw new IllegalArgumentException("Invalid capacity: " + capacity);
+ }
+ if (capacity >= MAXIMUM_CAPACITY) {
+ return MAXIMUM_CAPACITY;
+ }
+ return IntegerUtil.roundCeilLog2(capacity);
+ }
+
+ /** Callers must still use acquire when reading the value of the entry. */
+ protected final TableEntry<K, V> getEntryForOpaque(final K key) {
+ final int hash = SWMRHashTable.getHash(key);
+ final TableEntry<K, V>[] table = this.getTableAcquire();
+
+ for (TableEntry<K, V> curr = getAtIndexOpaque(table, hash & (table.length - 1)); curr != null; curr = curr.getNextOpaque()) {
+ if (hash == curr.hash && (key == curr.key || curr.key.equals(key))) {
+ return curr;
+ }
+ }
+
+ return null;
+ }
+
+ protected final TableEntry<K, V> getEntryForPlain(final K key) {
+ final int hash = SWMRHashTable.getHash(key);
+ final TableEntry<K, V>[] table = this.getTablePlain();
+
+ for (TableEntry<K, V> curr = table[hash & (table.length - 1)]; curr != null; curr = curr.getNextPlain()) {
+ if (hash == curr.hash && (key == curr.key || curr.key.equals(key))) {
+ return curr;
+ }
+ }
+
+ return null;
+ }
+
+ /* MT-Safe */
+
+ /** must be deterministic given a key */
+ private static int getHash(final Object key) {
+ int hash = key == null ? 0 : key.hashCode();
+ return HashUtil.mix(hash);
+ }
+
+ // rets -1 if capacity*loadFactor is too large
+ protected static int getTargetCapacity(final int capacity, final float loadFactor) {
+ final double ret = (double)capacity * (double)loadFactor;
+ if (Double.isInfinite(ret) || ret >= ((double)Integer.MAX_VALUE)) {
+ return -1;
+ }
+
+ return (int)ret;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean equals(final Object obj) {
+ if (this == obj) {
+ return true;
+ }
+ /* Make no attempt to deal with concurrent modifications */
+ if (!(obj instanceof Map<?, ?> other)) {
+ return false;
+ }
+
+ if (this.size() != other.size()) {
+ return false;
+ }
+
+ final TableEntry<K, V>[] table = this.getTableAcquire();
+
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ final V value = curr.getValueAcquire();
+
+ final Object otherValue = other.get(curr.key);
+ if (otherValue == null || (value != otherValue && value.equals(otherValue))) {
+ return false;
+ }
+ }
+ }
+
+ return true;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public int hashCode() {
+ /* Make no attempt to deal with concurrent modifications */
+ int hash = 0;
+ final TableEntry<K, V>[] table = this.getTableAcquire();
+
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ hash += curr.hashCode();
+ }
+ }
+
+ return hash;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public String toString() {
+ final StringBuilder builder = new StringBuilder(64);
+ builder.append("SWMRHashTable:{");
+
+ this.forEach((final K key, final V value) -> {
+ builder.append("{key: \"").append(key).append("\", value: \"").append(value).append("\"}");
+ });
+
+ return builder.append('}').toString();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public SWMRHashTable<K, V> clone() {
+ return new SWMRHashTable<>(this.getTableAcquire().length, this.loadFactor, this);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public Iterator<Map.Entry<K, V>> iterator() {
+ return new EntryIterator<>(this.getTableAcquire(), this);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void forEach(final Consumer<? super Map.Entry<K, V>> action) {
+ Validate.notNull(action, "Null action");
+
+ final TableEntry<K, V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ action.accept(curr);
+ }
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void forEach(final BiConsumer<? super K, ? super V> action) {
+ Validate.notNull(action, "Null action");
+
+ final TableEntry<K, V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ final V value = curr.getValueAcquire();
+
+ action.accept(curr.key, value);
+ }
+ }
+ }
+
+ /**
+ * Provides the specified consumer with all keys contained within this map.
+ * @param action The specified consumer.
+ */
+ public void forEachKey(final Consumer<? super K> action) {
+ Validate.notNull(action, "Null action");
+
+ final TableEntry<K, V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ action.accept(curr.key);
+ }
+ }
+ }
+
+ /**
+ * Provides the specified consumer with all values contained within this map. Equivalent to {@code map.values().forEach(Consumer)}.
+ * @param action The specified consumer.
+ */
+ public void forEachValue(final Consumer<? super V> action) {
+ Validate.notNull(action, "Null action");
+
+ final TableEntry<K, V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ final V value = curr.getValueAcquire();
+
+ action.accept(value);
+ }
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V get(final Object key) {
+ Validate.notNull(key, "Null key");
+
+ //noinspection unchecked
+ final TableEntry<K, V> entry = this.getEntryForOpaque((K)key);
+ return entry == null ? null : entry.getValueAcquire();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean containsKey(final Object key) {
+ Validate.notNull(key, "Null key");
+
+ // note: we need to use getValueAcquire, so that the reads from this map are ordered by acquire semantics
+ return this.get(key) != null;
+ }
+
+ /**
+ * Returns {@code true} if this map contains an entry with the specified key and value at some point during this call.
+ * @param key The specified key.
+ * @param value The specified value.
+ * @return {@code true} if this map contains an entry with the specified key and value.
+ */
+ public boolean contains(final Object key, final Object value) {
+ Validate.notNull(key, "Null key");
+
+ //noinspection unchecked
+ final TableEntry<K, V> entry = this.getEntryForOpaque((K)key);
+
+ if (entry == null) {
+ return false;
+ }
+
+ final V entryVal = entry.getValueAcquire();
+ return entryVal == value || entryVal.equals(value);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean containsValue(final Object value) {
+ Validate.notNull(value, "Null value");
+
+ final TableEntry<K, V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ final V currVal = curr.getValueAcquire();
+ if (currVal == value || currVal.equals(value)) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V getOrDefault(final Object key, final V defaultValue) {
+ Validate.notNull(key, "Null key");
+
+ //noinspection unchecked
+ final TableEntry<K, V> entry = this.getEntryForOpaque((K)key);
+
+ return entry == null ? defaultValue : entry.getValueAcquire();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public int size() {
+ return this.getSizeAcquire();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean isEmpty() {
+ return this.getSizeAcquire() == 0;
+ }
+
+ protected KeySet<K, V> keyset;
+ protected ValueCollection<K, V> values;
+ protected EntrySet<K, V> entrySet;
+
+ @Override
+ public Set<K> keySet() {
+ return this.keyset == null ? this.keyset = new KeySet<>(this) : this.keyset;
+ }
+
+ @Override
+ public Collection<V> values() {
+ return this.values == null ? this.values = new ValueCollection<>(this) : this.values;
+ }
+
+ @Override
+ public Set<Map.Entry<K, V>> entrySet() {
+ return this.entrySet == null ? this.entrySet = new EntrySet<>(this) : this.entrySet;
+ }
+
+ /* Non-MT-Safe */
+
+ protected int threshold;
+
+ protected final void checkResize(final int minCapacity) {
+ if (minCapacity <= this.threshold || this.threshold < 0) {
+ return;
+ }
+
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ int newCapacity = minCapacity >= MAXIMUM_CAPACITY ? MAXIMUM_CAPACITY : IntegerUtil.roundCeilLog2(minCapacity);
+ if (newCapacity < 0) {
+ newCapacity = MAXIMUM_CAPACITY;
+ }
+ if (newCapacity <= table.length) {
+ if (newCapacity == MAXIMUM_CAPACITY) {
+ return;
+ }
+ newCapacity = table.length << 1;
+ }
+
+ //noinspection unchecked
+ final TableEntry<K, V>[] newTable = new TableEntry[newCapacity];
+ final int indexMask = newCapacity - 1;
+
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> entry = table[i]; entry != null; entry = entry.getNextPlain()) {
+ final int hash = entry.hash;
+ final int index = hash & indexMask;
+
+ /* we need to create a new entry since there could be reading threads */
+ final TableEntry<K, V> insert = new TableEntry<>(hash, entry.key, entry.getValuePlain());
+
+ final TableEntry<K, V> prev = newTable[index];
+
+ newTable[index] = insert;
+ insert.setNextPlain(prev);
+ }
+ }
+
+ if (newCapacity == MAXIMUM_CAPACITY) {
+ this.threshold = -1; /* No more resizing */
+ } else {
+ this.threshold = getTargetCapacity(newCapacity, this.loadFactor);
+ }
+ this.setTableRelease(newTable); /* use release to publish entries in table */
+ }
+
+ protected final int addToSize(final int num) {
+ final int newSize = this.getSizePlain() + num;
+
+ this.setSizeOpaque(newSize);
+ this.checkResize(newSize);
+
+ return newSize;
+ }
+
+ protected final int removeFromSize(final int num) {
+ final int newSize = this.getSizePlain() - num;
+
+ this.setSizeOpaque(newSize);
+
+ return newSize;
+ }
+
+ /* Cannot be used to perform downsizing */
+ protected final int removeFromSizePlain(final int num) {
+ final int newSize = this.getSizePlain() - num;
+
+ this.setSizePlain(newSize);
+
+ return newSize;
+ }
+
+ protected final V put(final K key, final V value, final boolean onlyIfAbsent) {
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ final int hash = SWMRHashTable.getHash(key);
+ final int index = hash & (table.length - 1);
+
+ final TableEntry<K, V> head = table[index];
+ if (head == null) {
+ final TableEntry<K, V> insert = new TableEntry<>(hash, key, value);
+ setAtIndexRelease(table, index, insert);
+ this.addToSize(1);
+ return null;
+ }
+
+ for (TableEntry<K, V> curr = head;;) {
+ if (curr.hash == hash && (key == curr.key || curr.key.equals(key))) {
+ if (onlyIfAbsent) {
+ return curr.getValuePlain();
+ }
+
+ final V currVal = curr.getValuePlain();
+ curr.setValueRelease(value);
+ return currVal;
+ }
+
+ final TableEntry<K, V> next = curr.getNextPlain();
+ if (next != null) {
+ curr = next;
+ continue;
+ }
+
+ final TableEntry<K, V> insert = new TableEntry<>(hash, key, value);
+
+ curr.setNextRelease(insert);
+ this.addToSize(1);
+ return null;
+ }
+ }
+
+ /**
+ * Removes a key-value pair from this map if the specified predicate returns true. The specified predicate is
+ * tested with every entry in this map. Returns the number of key-value pairs removed.
+ * @param predicate The predicate to test key-value pairs against.
+ * @return The total number of key-value pairs removed from this map.
+ */
+ public int removeIf(final BiPredicate<K, V> predicate) {
+ Validate.notNull(predicate, "Null predicate");
+
+ int removed = 0;
+
+ final TableEntry<K, V>[] table = this.getTablePlain();
+
+ bin_iteration_loop:
+ for (int i = 0, len = table.length; i < len; ++i) {
+ TableEntry<K, V> curr = table[i];
+ if (curr == null) {
+ continue;
+ }
+
+ /* Handle bin nodes first */
+ while (predicate.test(curr.key, curr.getValuePlain())) {
+ ++removed;
+ this.removeFromSizePlain(1); /* required in case predicate throws an exception */
+
+ setAtIndexRelease(table, i, curr = curr.getNextPlain());
+
+ if (curr == null) {
+ continue bin_iteration_loop;
+ }
+ }
+
+ TableEntry<K, V> prev;
+
+ /* curr at this point is the bin node */
+
+ for (prev = curr, curr = curr.getNextPlain(); curr != null;) {
+ /* If we want to remove, then we should hold prev, as it will be a valid entry to link on */
+ if (predicate.test(curr.key, curr.getValuePlain())) {
+ ++removed;
+ this.removeFromSizePlain(1); /* required in case predicate throws an exception */
+
+ prev.setNextRelease(curr = curr.getNextPlain());
+ } else {
+ prev = curr;
+ curr = curr.getNextPlain();
+ }
+ }
+ }
+
+ return removed;
+ }
+
+ /**
+ * Removes a key-value pair from this map if the specified predicate returns true. The specified predicate is
+ * tested with every entry in this map. Returns the number of key-value pairs removed.
+ * @param predicate The predicate to test key-value pairs against.
+ * @return The total number of key-value pairs removed from this map.
+ */
+ public int removeEntryIf(final Predicate<? super Map.Entry<K, V>> predicate) {
+ Validate.notNull(predicate, "Null predicate");
+
+ int removed = 0;
+
+ final TableEntry<K, V>[] table = this.getTablePlain();
+
+ bin_iteration_loop:
+ for (int i = 0, len = table.length; i < len; ++i) {
+ TableEntry<K, V> curr = table[i];
+ if (curr == null) {
+ continue;
+ }
+
+ /* Handle bin nodes first */
+ while (predicate.test(curr)) {
+ ++removed;
+ this.removeFromSizePlain(1); /* required in case predicate throws an exception */
+
+ setAtIndexRelease(table, i, curr = curr.getNextPlain());
+
+ if (curr == null) {
+ continue bin_iteration_loop;
+ }
+ }
+
+ TableEntry<K, V> prev;
+
+ /* curr at this point is the bin node */
+
+ for (prev = curr, curr = curr.getNextPlain(); curr != null;) {
+ /* If we want to remove, then we should hold prev, as it will be a valid entry to link on */
+ if (predicate.test(curr)) {
+ ++removed;
+ this.removeFromSizePlain(1); /* required in case predicate throws an exception */
+
+ prev.setNextRelease(curr = curr.getNextPlain());
+ } else {
+ prev = curr;
+ curr = curr.getNextPlain();
+ }
+ }
+ }
+
+ return removed;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V put(final K key, final V value) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(value, "Null value");
+
+ return this.put(key, value, false);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V putIfAbsent(final K key, final V value) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(value, "Null value");
+
+ return this.put(key, value, true);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean remove(final Object key, final Object value) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(value, "Null value");
+
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ final int hash = SWMRHashTable.getHash(key);
+ final int index = hash & (table.length - 1);
+
+ final TableEntry<K, V> head = table[index];
+ if (head == null) {
+ return false;
+ }
+
+ if (head.hash == hash && (head.key == key || head.key.equals(key))) {
+ final V currVal = head.getValuePlain();
+
+ if (currVal != value && !currVal.equals(value)) {
+ return false;
+ }
+
+ setAtIndexRelease(table, index, head.getNextPlain());
+ this.removeFromSize(1);
+
+ return true;
+ }
+
+ for (TableEntry<K, V> curr = head.getNextPlain(), prev = head; curr != null; prev = curr, curr = curr.getNextPlain()) {
+ if (curr.hash == hash && (curr.key == key || curr.key.equals(key))) {
+ final V currVal = curr.getValuePlain();
+
+ if (currVal != value && !currVal.equals(value)) {
+ return false;
+ }
+
+ prev.setNextRelease(curr.getNextPlain());
+ this.removeFromSize(1);
+
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ protected final V remove(final Object key, final int hash) {
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ final int index = (table.length - 1) & hash;
+
+ final TableEntry<K, V> head = table[index];
+ if (head == null) {
+ return null;
+ }
+
+ if (hash == head.hash && (head.key == key || head.key.equals(key))) {
+ setAtIndexRelease(table, index, head.getNextPlain());
+ this.removeFromSize(1);
+
+ return head.getValuePlain();
+ }
+
+ for (TableEntry<K, V> curr = head.getNextPlain(), prev = head; curr != null; prev = curr, curr = curr.getNextPlain()) {
+ if (curr.hash == hash && (key == curr.key || curr.key.equals(key))) {
+ prev.setNextRelease(curr.getNextPlain());
+ this.removeFromSize(1);
+
+ return curr.getValuePlain();
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V remove(final Object key) {
+ Validate.notNull(key, "Null key");
+
+ return this.remove(key, SWMRHashTable.getHash(key));
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean replace(final K key, final V oldValue, final V newValue) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(oldValue, "Null oldValue");
+ Validate.notNull(newValue, "Null newValue");
+
+ final TableEntry<K, V> entry = this.getEntryForPlain(key);
+ if (entry == null) {
+ return false;
+ }
+
+ final V currValue = entry.getValuePlain();
+ if (currValue == oldValue || currValue.equals(oldValue)) {
+ entry.setValueRelease(newValue);
+ return true;
+ }
+
+ return false;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V replace(final K key, final V value) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(value, "Null value");
+
+ final TableEntry<K, V> entry = this.getEntryForPlain(key);
+ if (entry == null) {
+ return null;
+ }
+
+ final V prev = entry.getValuePlain();
+ entry.setValueRelease(value);
+ return prev;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void replaceAll(final BiFunction<? super K, ? super V, ? extends V> function) {
+ Validate.notNull(function, "Null function");
+
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<K, V> curr = table[i]; curr != null; curr = curr.getNextPlain()) {
+ final V value = curr.getValuePlain();
+
+ final V newValue = function.apply(curr.key, value);
+ if (newValue == null) {
+ throw new NullPointerException();
+ }
+
+ curr.setValueRelease(newValue);
+ }
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void putAll(final Map<? extends K, ? extends V> map) {
+ Validate.notNull(map, "Null map");
+
+ final int size = map.size();
+ this.checkResize(Math.max(this.getSizePlain() + size/2, size)); /* preemptively resize */
+ map.forEach(this::put);
+ }
+
+ /**
+ * {@inheritDoc}
+ * <p>
+ * This call is non-atomic and the order that which entries are removed is undefined. The clear operation itself
+ * is release ordered, that is, after the clear operation is performed a release fence is performed.
+ * </p>
+ */
+ @Override
+ public void clear() {
+ Arrays.fill(this.getTablePlain(), null);
+ this.setSizeRelease(0);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V compute(final K key, final BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(remappingFunction, "Null remappingFunction");
+
+ final int hash = SWMRHashTable.getHash(key);
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ final int index = hash & (table.length - 1);
+
+ for (TableEntry<K, V> curr = table[index], prev = null;;prev = curr, curr = curr.getNextPlain()) {
+ if (curr == null) {
+ final V newVal = remappingFunction.apply(key ,null);
+
+ if (newVal == null) {
+ return null;
+ }
+
+ final TableEntry<K, V> insert = new TableEntry<>(hash, key, newVal);
+ if (prev == null) {
+ setAtIndexRelease(table, index, insert);
+ } else {
+ prev.setNextRelease(insert);
+ }
+
+ this.addToSize(1);
+
+ return newVal;
+ }
+
+ if (curr.hash == hash && (curr.key == key || curr.key.equals(key))) {
+ final V newVal = remappingFunction.apply(key, curr.getValuePlain());
+
+ if (newVal != null) {
+ curr.setValueRelease(newVal);
+ return newVal;
+ }
+
+ if (prev == null) {
+ setAtIndexRelease(table, index, curr.getNextPlain());
+ } else {
+ prev.setNextRelease(curr.getNextPlain());
+ }
+
+ this.removeFromSize(1);
+
+ return null;
+ }
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V computeIfPresent(final K key, final BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(remappingFunction, "Null remappingFunction");
+
+ final int hash = SWMRHashTable.getHash(key);
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ final int index = hash & (table.length - 1);
+
+ for (TableEntry<K, V> curr = table[index], prev = null; curr != null; prev = curr, curr = curr.getNextPlain()) {
+ if (curr.hash != hash || (curr.key != key && !curr.key.equals(key))) {
+ continue;
+ }
+
+ final V newVal = remappingFunction.apply(key, curr.getValuePlain());
+ if (newVal != null) {
+ curr.setValueRelease(newVal);
+ return newVal;
+ }
+
+ if (prev == null) {
+ setAtIndexRelease(table, index, curr.getNextPlain());
+ } else {
+ prev.setNextRelease(curr.getNextPlain());
+ }
+
+ this.removeFromSize(1);
+
+ return null;
+ }
+
+ return null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V computeIfAbsent(final K key, final Function<? super K, ? extends V> mappingFunction) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(mappingFunction, "Null mappingFunction");
+
+ final int hash = SWMRHashTable.getHash(key);
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ final int index = hash & (table.length - 1);
+
+ for (TableEntry<K, V> curr = table[index], prev = null;;prev = curr, curr = curr.getNextPlain()) {
+ if (curr != null) {
+ if (curr.hash == hash && (curr.key == key || curr.key.equals(key))) {
+ return curr.getValuePlain();
+ }
+ continue;
+ }
+
+ final V newVal = mappingFunction.apply(key);
+
+ if (newVal == null) {
+ return null;
+ }
+
+ final TableEntry<K, V> insert = new TableEntry<>(hash, key, newVal);
+ if (prev == null) {
+ setAtIndexRelease(table, index, insert);
+ } else {
+ prev.setNextRelease(insert);
+ }
+
+ this.addToSize(1);
+
+ return newVal;
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public V merge(final K key, final V value, final BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
+ Validate.notNull(key, "Null key");
+ Validate.notNull(value, "Null value");
+ Validate.notNull(remappingFunction, "Null remappingFunction");
+
+ final int hash = SWMRHashTable.getHash(key);
+ final TableEntry<K, V>[] table = this.getTablePlain();
+ final int index = hash & (table.length - 1);
+
+ for (TableEntry<K, V> curr = table[index], prev = null;;prev = curr, curr = curr.getNextPlain()) {
+ if (curr == null) {
+ final TableEntry<K, V> insert = new TableEntry<>(hash, key, value);
+ if (prev == null) {
+ setAtIndexRelease(table, index, insert);
+ } else {
+ prev.setNextRelease(insert);
+ }
+
+ this.addToSize(1);
+
+ return value;
+ }
+
+ if (curr.hash == hash && (curr.key == key || curr.key.equals(key))) {
+ final V newVal = remappingFunction.apply(curr.getValuePlain(), value);
+
+ if (newVal != null) {
+ curr.setValueRelease(newVal);
+ return newVal;
+ }
+
+ if (prev == null) {
+ setAtIndexRelease(table, index, curr.getNextPlain());
+ } else {
+ prev.setNextRelease(curr.getNextPlain());
+ }
+
+ this.removeFromSize(1);
+
+ return null;
+ }
+ }
+ }
+
+ protected static final class TableEntry<K, V> implements Map.Entry<K, V> {
+
+ protected static final VarHandle TABLE_ENTRY_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(TableEntry[].class);
+
+ protected final int hash;
+ protected final K key;
+ protected V value;
+
+ protected TableEntry<K, V> next;
+
+ protected static final VarHandle VALUE_HANDLE = ConcurrentUtil.getVarHandle(TableEntry.class, "value", Object.class);
+ protected static final VarHandle NEXT_HANDLE = ConcurrentUtil.getVarHandle(TableEntry.class, "next", TableEntry.class);
+
+ /* value */
+
+ protected final V getValuePlain() {
+ //noinspection unchecked
+ return (V)VALUE_HANDLE.get(this);
+ }
+
+ protected final V getValueAcquire() {
+ //noinspection unchecked
+ return (V)VALUE_HANDLE.getAcquire(this);
+ }
+
+ protected final void setValueRelease(final V to) {
+ VALUE_HANDLE.setRelease(this, to);
+ }
+
+ /* next */
+
+ protected final TableEntry<K, V> getNextPlain() {
+ //noinspection unchecked
+ return (TableEntry<K, V>)NEXT_HANDLE.get(this);
+ }
+
+ protected final TableEntry<K, V> getNextOpaque() {
+ //noinspection unchecked
+ return (TableEntry<K, V>)NEXT_HANDLE.getOpaque(this);
+ }
+
+ protected final void setNextPlain(final TableEntry<K, V> next) {
+ NEXT_HANDLE.set(this, next);
+ }
+
+ protected final void setNextRelease(final TableEntry<K, V> next) {
+ NEXT_HANDLE.setRelease(this, next);
+ }
+
+ protected TableEntry(final int hash, final K key, final V value) {
+ this.hash = hash;
+ this.key = key;
+ this.value = value;
+ }
+
+ @Override
+ public K getKey() {
+ return this.key;
+ }
+
+ @Override
+ public V getValue() {
+ return this.getValueAcquire();
+ }
+
+ @Override
+ public V setValue(final V value) {
+ throw new UnsupportedOperationException();
+ }
+
+ protected static int hash(final Object key, final Object value) {
+ return key.hashCode() ^ (value == null ? 0 : value.hashCode());
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public int hashCode() {
+ return hash(this.key, this.getValueAcquire());
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean equals(final Object obj) {
+ if (this == obj) {
+ return true;
+ }
+
+ if (!(obj instanceof Map.Entry<?, ?> other)) {
+ return false;
+ }
+ final Object otherKey = other.getKey();
+ final Object otherValue = other.getValue();
+
+ final K thisKey = this.getKey();
+ final V thisVal = this.getValueAcquire();
+ return (thisKey == otherKey || thisKey.equals(otherKey)) &&
+ (thisVal == otherValue || thisVal.equals(otherValue));
+ }
+ }
+
+
+ protected static abstract class TableEntryIterator<K, V, T> implements Iterator<T> {
+
+ protected final TableEntry<K, V>[] table;
+ protected final SWMRHashTable<K, V> map;
+
+ /* bin which our current element resides on */
+ protected int tableIndex;
+
+ protected TableEntry<K, V> currEntry; /* curr entry, null if no more to iterate or if curr was removed or if we've just init'd */
+ protected TableEntry<K, V> nextEntry; /* may not be on the same bin as currEntry */
+
+ protected TableEntryIterator(final TableEntry<K, V>[] table, final SWMRHashTable<K, V> map) {
+ this.table = table;
+ this.map = map;
+ int tableIndex = 0;
+ for (int len = table.length; tableIndex < len; ++tableIndex) {
+ final TableEntry<K, V> entry = getAtIndexOpaque(table, tableIndex);
+ if (entry != null) {
+ this.nextEntry = entry;
+ this.tableIndex = tableIndex + 1;
+ return;
+ }
+ }
+ this.tableIndex = tableIndex;
+ }
+
+ @Override
+ public boolean hasNext() {
+ return this.nextEntry != null;
+ }
+
+ protected final TableEntry<K, V> advanceEntry() {
+ final TableEntry<K, V>[] table = this.table;
+ final int tableLength = table.length;
+ int tableIndex = this.tableIndex;
+ final TableEntry<K, V> curr = this.nextEntry;
+ if (curr == null) {
+ return null;
+ }
+
+ this.currEntry = curr;
+
+ // set up nextEntry
+
+ // find next in chain
+ TableEntry<K, V> next = curr.getNextOpaque();
+
+ if (next != null) {
+ this.nextEntry = next;
+ return curr;
+ }
+
+ // nothing in chain, so find next available bin
+ for (;tableIndex < tableLength; ++tableIndex) {
+ next = getAtIndexOpaque(table, tableIndex);
+ if (next != null) {
+ this.nextEntry = next;
+ this.tableIndex = tableIndex + 1;
+ return curr;
+ }
+ }
+
+ this.nextEntry = null;
+ this.tableIndex = tableIndex;
+ return curr;
+ }
+
+ @Override
+ public void remove() {
+ final TableEntry<K, V> curr = this.currEntry;
+ if (curr == null) {
+ throw new IllegalStateException();
+ }
+
+ this.map.remove(curr.key, curr.hash);
+
+ this.currEntry = null;
+ }
+ }
+
+ protected static final class ValueIterator<K, V> extends TableEntryIterator<K, V, V> {
+
+ protected ValueIterator(final TableEntry<K, V>[] table, final SWMRHashTable<K, V> map) {
+ super(table, map);
+ }
+
+ @Override
+ public V next() {
+ final TableEntry<K, V> entry = this.advanceEntry();
+
+ if (entry == null) {
+ throw new NoSuchElementException();
+ }
+
+ return entry.getValueAcquire();
+ }
+ }
+
+ protected static final class KeyIterator<K, V> extends TableEntryIterator<K, V, K> {
+
+ protected KeyIterator(final TableEntry<K, V>[] table, final SWMRHashTable<K, V> map) {
+ super(table, map);
+ }
+
+ @Override
+ public K next() {
+ final TableEntry<K, V> curr = this.advanceEntry();
+
+ if (curr == null) {
+ throw new NoSuchElementException();
+ }
+
+ return curr.key;
+ }
+ }
+
+ protected static final class EntryIterator<K, V> extends TableEntryIterator<K, V, Map.Entry<K, V>> {
+
+ protected EntryIterator(final TableEntry<K, V>[] table, final SWMRHashTable<K, V> map) {
+ super(table, map);
+ }
+
+ @Override
+ public Map.Entry<K, V> next() {
+ final TableEntry<K, V> curr = this.advanceEntry();
+
+ if (curr == null) {
+ throw new NoSuchElementException();
+ }
+
+ return curr;
+ }
+ }
+
+ protected static abstract class ViewCollection<K, V, T> implements Collection<T> {
+
+ protected final SWMRHashTable<K, V> map;
+
+ protected ViewCollection(final SWMRHashTable<K, V> map) {
+ this.map = map;
+ }
+
+ @Override
+ public boolean add(final T element) {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public boolean addAll(final Collection<? extends T> collections) {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public boolean removeAll(final Collection<?> collection) {
+ Validate.notNull(collection, "Null collection");
+
+ boolean modified = false;
+ for (final Object element : collection) {
+ modified |= this.remove(element);
+ }
+ return modified;
+ }
+
+ @Override
+ public int size() {
+ return this.map.size();
+ }
+
+ @Override
+ public boolean isEmpty() {
+ return this.size() == 0;
+ }
+
+ @Override
+ public void clear() {
+ this.map.clear();
+ }
+
+ @Override
+ public boolean containsAll(final Collection<?> collection) {
+ Validate.notNull(collection, "Null collection");
+
+ for (final Object element : collection) {
+ if (!this.contains(element)) {
+ return false;
+ }
+ }
+
+ return true;
+ }
+
+ @Override
+ public Object[] toArray() {
+ final List<T> list = new ArrayList<>(this.size());
+
+ this.forEach(list::add);
+
+ return list.toArray();
+ }
+
+ @Override
+ public <E> E[] toArray(final E[] array) {
+ final List<T> list = new ArrayList<>(this.size());
+
+ this.forEach(list::add);
+
+ return list.toArray(array);
+ }
+
+ @Override
+ public <E> E[] toArray(final IntFunction<E[]> generator) {
+ final List<T> list = new ArrayList<>(this.size());
+
+ this.forEach(list::add);
+
+ return list.toArray(generator);
+ }
+
+ @Override
+ public int hashCode() {
+ int hash = 0;
+ for (final T element : this) {
+ hash += element == null ? 0 : element.hashCode();
+ }
+ return hash;
+ }
+
+ @Override
+ public Spliterator<T> spliterator() { // TODO implement
+ return Spliterators.spliterator(this, Spliterator.NONNULL);
+ }
+ }
+
+ protected static abstract class ViewSet<K, V, T> extends ViewCollection<K, V, T> implements Set<T> {
+
+ protected ViewSet(final SWMRHashTable<K, V> map) {
+ super(map);
+ }
+
+ @Override
+ public boolean equals(final Object obj) {
+ if (this == obj) {
+ return true;
+ }
+
+ if (!(obj instanceof Set)) {
+ return false;
+ }
+
+ final Set<?> other = (Set<?>)obj;
+ if (other.size() != this.size()) {
+ return false;
+ }
+
+ return this.containsAll(other);
+ }
+ }
+
+ protected static final class EntrySet<K, V> extends ViewSet<K, V, Map.Entry<K, V>> implements Set<Map.Entry<K, V>> {
+
+ protected EntrySet(final SWMRHashTable<K, V> map) {
+ super(map);
+ }
+
+ @Override
+ public boolean remove(final Object object) {
+ if (!(object instanceof Map.Entry<?, ?> entry)) {
+ return false;
+ }
+
+ final Object key;
+ final Object value;
+
+ try {
+ key = entry.getKey();
+ value = entry.getValue();
+ } catch (final IllegalStateException ex) {
+ return false;
+ }
+
+ return this.map.remove(key, value);
+ }
+
+ @Override
+ public boolean removeIf(final Predicate<? super Map.Entry<K, V>> filter) {
+ Validate.notNull(filter, "Null filter");
+
+ return this.map.removeEntryIf(filter) != 0;
+ }
+
+ @Override
+ public boolean retainAll(final Collection<?> collection) {
+ Validate.notNull(collection, "Null collection");
+
+ return this.map.removeEntryIf((final Map.Entry<K, V> entry) -> {
+ return !collection.contains(entry);
+ }) != 0;
+ }
+
+ @Override
+ public Iterator<Map.Entry<K, V>> iterator() {
+ return new EntryIterator<>(this.map.getTableAcquire(), this.map);
+ }
+
+ @Override
+ public void forEach(final Consumer<? super Map.Entry<K, V>> action) {
+ this.map.forEach(action);
+ }
+
+ @Override
+ public boolean contains(final Object object) {
+ if (!(object instanceof Map.Entry<?, ?> entry)) {
+ return false;
+ }
+
+ final Object key;
+ final Object value;
+
+ try {
+ key = entry.getKey();
+ value = entry.getValue();
+ } catch (final IllegalStateException ex) {
+ return false;
+ }
+
+ return this.map.contains(key, value);
+ }
+
+ @Override
+ public String toString() {
+ return CollectionUtil.toString(this, "SWMRHashTableEntrySet");
+ }
+ }
+
+ protected static final class KeySet<K, V> extends ViewSet<K, V, K> {
+
+ protected KeySet(final SWMRHashTable<K, V> map) {
+ super(map);
+ }
+
+ @Override
+ public Iterator<K> iterator() {
+ return new KeyIterator<>(this.map.getTableAcquire(), this.map);
+ }
+
+ @Override
+ public void forEach(final Consumer<? super K> action) {
+ Validate.notNull(action, "Null action");
+
+ this.map.forEachKey(action);
+ }
+
+ @Override
+ public boolean contains(final Object key) {
+ Validate.notNull(key, "Null key");
+
+ return this.map.containsKey(key);
+ }
+
+ @Override
+ public boolean remove(final Object key) {
+ Validate.notNull(key, "Null key");
+
+ return this.map.remove(key) != null;
+ }
+
+ @Override
+ public boolean retainAll(final Collection<?> collection) {
+ Validate.notNull(collection, "Null collection");
+
+ return this.map.removeIf((final K key, final V value) -> {
+ return !collection.contains(key);
+ }) != 0;
+ }
+
+ @Override
+ public boolean removeIf(final Predicate<? super K> filter) {
+ Validate.notNull(filter, "Null filter");
+
+ return this.map.removeIf((final K key, final V value) -> {
+ return filter.test(key);
+ }) != 0;
+ }
+
+ @Override
+ public String toString() {
+ return CollectionUtil.toString(this, "SWMRHashTableKeySet");
+ }
+ }
+
+ protected static final class ValueCollection<K, V> extends ViewSet<K, V, V> implements Collection<V> {
+
+ protected ValueCollection(final SWMRHashTable<K, V> map) {
+ super(map);
+ }
+
+ @Override
+ public Iterator<V> iterator() {
+ return new ValueIterator<>(this.map.getTableAcquire(), this.map);
+ }
+
+ @Override
+ public void forEach(final Consumer<? super V> action) {
+ Validate.notNull(action, "Null action");
+
+ this.map.forEachValue(action);
+ }
+
+ @Override
+ public boolean contains(final Object object) {
+ Validate.notNull(object, "Null object");
+
+ return this.map.containsValue(object);
+ }
+
+ @Override
+ public boolean remove(final Object object) {
+ Validate.notNull(object, "Null object");
+
+ final Iterator<V> itr = this.iterator();
+ while (itr.hasNext()) {
+ final V val = itr.next();
+ if (val == object || val.equals(object)) {
+ itr.remove();
+ return true;
+ }
+ }
+
+ return false;
+ }
+
+ @Override
+ public boolean removeIf(final Predicate<? super V> filter) {
+ Validate.notNull(filter, "Null filter");
+
+ return this.map.removeIf((final K key, final V value) -> {
+ return filter.test(value);
+ }) != 0;
+ }
+
+ @Override
+ public boolean retainAll(final Collection<?> collection) {
+ Validate.notNull(collection, "Null collection");
+
+ return this.map.removeIf((final K key, final V value) -> {
+ return !collection.contains(value);
+ }) != 0;
+ }
+
+ @Override
+ public String toString() {
+ return CollectionUtil.toString(this, "SWMRHashTableValues");
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/map/SWMRLong2ObjectHashTable.java b/src/main/java/ca/spottedleaf/concurrentutil/map/SWMRLong2ObjectHashTable.java
new file mode 100644
index 0000000000000000000000000000000000000000..bb301a9f4e3ac919552eef68afc73569d50674db
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/map/SWMRLong2ObjectHashTable.java
@@ -0,0 +1,674 @@
+package ca.spottedleaf.concurrentutil.map;
+
+import ca.spottedleaf.concurrentutil.function.BiLongObjectConsumer;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import ca.spottedleaf.concurrentutil.util.HashUtil;
+import ca.spottedleaf.concurrentutil.util.IntegerUtil;
+import ca.spottedleaf.concurrentutil.util.Validate;
+import java.lang.invoke.VarHandle;
+import java.util.Arrays;
+import java.util.function.Consumer;
+import java.util.function.LongConsumer;
+
+// trimmed down version of SWMRHashTable
+public class SWMRLong2ObjectHashTable<V> {
+
+ protected int size;
+
+ protected TableEntry<V>[] table;
+
+ protected final float loadFactor;
+
+ protected static final VarHandle SIZE_HANDLE = ConcurrentUtil.getVarHandle(SWMRLong2ObjectHashTable.class, "size", int.class);
+ protected static final VarHandle TABLE_HANDLE = ConcurrentUtil.getVarHandle(SWMRLong2ObjectHashTable.class, "table", TableEntry[].class);
+
+ /* size */
+
+ protected final int getSizePlain() {
+ return (int)SIZE_HANDLE.get(this);
+ }
+
+ protected final int getSizeOpaque() {
+ return (int)SIZE_HANDLE.getOpaque(this);
+ }
+
+ protected final int getSizeAcquire() {
+ return (int)SIZE_HANDLE.getAcquire(this);
+ }
+
+ protected final void setSizePlain(final int value) {
+ SIZE_HANDLE.set(this, value);
+ }
+
+ protected final void setSizeOpaque(final int value) {
+ SIZE_HANDLE.setOpaque(this, value);
+ }
+
+ protected final void setSizeRelease(final int value) {
+ SIZE_HANDLE.setRelease(this, value);
+ }
+
+ /* table */
+
+ protected final TableEntry<V>[] getTablePlain() {
+ //noinspection unchecked
+ return (TableEntry<V>[])TABLE_HANDLE.get(this);
+ }
+
+ protected final TableEntry<V>[] getTableAcquire() {
+ //noinspection unchecked
+ return (TableEntry<V>[])TABLE_HANDLE.getAcquire(this);
+ }
+
+ protected final void setTablePlain(final TableEntry<V>[] table) {
+ TABLE_HANDLE.set(this, table);
+ }
+
+ protected final void setTableRelease(final TableEntry<V>[] table) {
+ TABLE_HANDLE.setRelease(this, table);
+ }
+
+ protected static final int DEFAULT_CAPACITY = 16;
+ protected static final float DEFAULT_LOAD_FACTOR = 0.75f;
+ protected static final int MAXIMUM_CAPACITY = Integer.MIN_VALUE >>> 1;
+
+ /**
+ * Constructs this map with a capacity of {@code 16} and load factor of {@code 0.75f}.
+ */
+ public SWMRLong2ObjectHashTable() {
+ this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR);
+ }
+
+ /**
+ * Constructs this map with the specified capacity and load factor of {@code 0.75f}.
+ * @param capacity specified initial capacity, > 0
+ */
+ public SWMRLong2ObjectHashTable(final int capacity) {
+ this(capacity, DEFAULT_LOAD_FACTOR);
+ }
+
+ /**
+ * Constructs this map with the specified capacity and load factor.
+ * @param capacity specified capacity, > 0
+ * @param loadFactor specified load factor, > 0 && finite
+ */
+ public SWMRLong2ObjectHashTable(final int capacity, final float loadFactor) {
+ final int tableSize = getCapacityFor(capacity);
+
+ if (loadFactor <= 0.0 || !Float.isFinite(loadFactor)) {
+ throw new IllegalArgumentException("Invalid load factor: " + loadFactor);
+ }
+
+ //noinspection unchecked
+ final TableEntry<V>[] table = new TableEntry[tableSize];
+ this.setTablePlain(table);
+
+ if (tableSize == MAXIMUM_CAPACITY) {
+ this.threshold = -1;
+ } else {
+ this.threshold = getTargetCapacity(tableSize, loadFactor);
+ }
+
+ this.loadFactor = loadFactor;
+ }
+
+ /**
+ * Constructs this map with a capacity of {@code 16} or the specified map's size, whichever is larger, and
+ * with a load factor of {@code 0.75f}.
+ * All of the specified map's entries are copied into this map.
+ * @param other The specified map.
+ */
+ public SWMRLong2ObjectHashTable(final SWMRLong2ObjectHashTable<V> other) {
+ this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, other);
+ }
+
+ /**
+ * Constructs this map with a minimum capacity of the specified capacity or the specified map's size, whichever is larger, and
+ * with a load factor of {@code 0.75f}.
+ * All of the specified map's entries are copied into this map.
+ * @param capacity specified capacity, > 0
+ * @param other The specified map.
+ */
+ public SWMRLong2ObjectHashTable(final int capacity, final SWMRLong2ObjectHashTable<V> other) {
+ this(capacity, DEFAULT_LOAD_FACTOR, other);
+ }
+
+ /**
+ * Constructs this map with a min capacity of the specified capacity or the specified map's size, whichever is larger, and
+ * with the specified load factor.
+ * All of the specified map's entries are copied into this map.
+ * @param capacity specified capacity, > 0
+ * @param loadFactor specified load factor, > 0 && finite
+ * @param other The specified map.
+ */
+ public SWMRLong2ObjectHashTable(final int capacity, final float loadFactor, final SWMRLong2ObjectHashTable<V> other) {
+ this(Math.max(Validate.notNull(other, "Null map").size(), capacity), loadFactor);
+ this.putAll(other);
+ }
+
+ protected static <V> TableEntry<V> getAtIndexOpaque(final TableEntry<V>[] table, final int index) {
+ // noinspection unchecked
+ return (TableEntry<V>)TableEntry.TABLE_ENTRY_ARRAY_HANDLE.getOpaque(table, index);
+ }
+
+ protected static <V> void setAtIndexRelease(final TableEntry<V>[] table, final int index, final TableEntry<V> value) {
+ TableEntry.TABLE_ENTRY_ARRAY_HANDLE.setRelease(table, index, value);
+ }
+
+ public final float getLoadFactor() {
+ return this.loadFactor;
+ }
+
+ protected static int getCapacityFor(final int capacity) {
+ if (capacity <= 0) {
+ throw new IllegalArgumentException("Invalid capacity: " + capacity);
+ }
+ if (capacity >= MAXIMUM_CAPACITY) {
+ return MAXIMUM_CAPACITY;
+ }
+ return IntegerUtil.roundCeilLog2(capacity);
+ }
+
+ /** Callers must still use acquire when reading the value of the entry. */
+ protected final TableEntry<V> getEntryForOpaque(final long key) {
+ final int hash = SWMRLong2ObjectHashTable.getHash(key);
+ final TableEntry<V>[] table = this.getTableAcquire();
+
+ for (TableEntry<V> curr = getAtIndexOpaque(table, hash & (table.length - 1)); curr != null; curr = curr.getNextOpaque()) {
+ if (key == curr.key) {
+ return curr;
+ }
+ }
+
+ return null;
+ }
+
+ protected final TableEntry<V> getEntryForPlain(final long key) {
+ final int hash = SWMRLong2ObjectHashTable.getHash(key);
+ final TableEntry<V>[] table = this.getTablePlain();
+
+ for (TableEntry<V> curr = table[hash & (table.length - 1)]; curr != null; curr = curr.getNextPlain()) {
+ if (key == curr.key) {
+ return curr;
+ }
+ }
+
+ return null;
+ }
+
+ /* MT-Safe */
+
+ /** must be deterministic given a key */
+ protected static int getHash(final long key) {
+ return (int)HashUtil.mix(key);
+ }
+
+ // rets -1 if capacity*loadFactor is too large
+ protected static int getTargetCapacity(final int capacity, final float loadFactor) {
+ final double ret = (double)capacity * (double)loadFactor;
+ if (Double.isInfinite(ret) || ret >= ((double)Integer.MAX_VALUE)) {
+ return -1;
+ }
+
+ return (int)ret;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public boolean equals(final Object obj) {
+ if (this == obj) {
+ return true;
+ }
+ /* Make no attempt to deal with concurrent modifications */
+ if (!(obj instanceof SWMRLong2ObjectHashTable<?> other)) {
+ return false;
+ }
+
+ if (this.size() != other.size()) {
+ return false;
+ }
+
+ final TableEntry<V>[] table = this.getTableAcquire();
+
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ final V value = curr.getValueAcquire();
+
+ final Object otherValue = other.get(curr.key);
+ if (otherValue == null || (value != otherValue && value.equals(otherValue))) {
+ return false;
+ }
+ }
+ }
+
+ return true;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public int hashCode() {
+ /* Make no attempt to deal with concurrent modifications */
+ int hash = 0;
+ final TableEntry<V>[] table = this.getTableAcquire();
+
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ hash += curr.hashCode();
+ }
+ }
+
+ return hash;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public String toString() {
+ final StringBuilder builder = new StringBuilder(64);
+ builder.append("SingleWriterMultiReaderHashMap:{");
+
+ this.forEach((final long key, final V value) -> {
+ builder.append("{key: \"").append(key).append("\", value: \"").append(value).append("\"}");
+ });
+
+ return builder.append('}').toString();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public SWMRLong2ObjectHashTable<V> clone() {
+ return new SWMRLong2ObjectHashTable<>(this.getTableAcquire().length, this.loadFactor, this);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public void forEach(final Consumer<? super TableEntry<V>> action) {
+ Validate.notNull(action, "Null action");
+
+ final TableEntry<V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ action.accept(curr);
+ }
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public void forEach(final BiLongObjectConsumer<? super V> action) {
+ Validate.notNull(action, "Null action");
+
+ final TableEntry<V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ final V value = curr.getValueAcquire();
+
+ action.accept(curr.key, value);
+ }
+ }
+ }
+
+ /**
+ * Provides the specified consumer with all keys contained within this map.
+ * @param action The specified consumer.
+ */
+ public void forEachKey(final LongConsumer action) {
+ Validate.notNull(action, "Null action");
+
+ final TableEntry<V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ action.accept(curr.key);
+ }
+ }
+ }
+
+ /**
+ * Provides the specified consumer with all values contained within this map. Equivalent to {@code map.values().forEach(Consumer)}.
+ * @param action The specified consumer.
+ */
+ public void forEachValue(final Consumer<? super V> action) {
+ Validate.notNull(action, "Null action");
+
+ final TableEntry<V>[] table = this.getTableAcquire();
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<V> curr = getAtIndexOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+ final V value = curr.getValueAcquire();
+
+ action.accept(value);
+ }
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public V get(final long key) {
+ final TableEntry<V> entry = this.getEntryForOpaque(key);
+ return entry == null ? null : entry.getValueAcquire();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public boolean containsKey(final long key) {
+ // note: we need to use getValueAcquire, so that the reads from this map are ordered by acquire semantics
+ return this.get(key) != null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public V getOrDefault(final long key, final V defaultValue) {
+ final TableEntry<V> entry = this.getEntryForOpaque(key);
+
+ return entry == null ? defaultValue : entry.getValueAcquire();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public int size() {
+ return this.getSizeAcquire();
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public boolean isEmpty() {
+ return this.getSizeAcquire() == 0;
+ }
+
+ /* Non-MT-Safe */
+
+ protected int threshold;
+
+ protected final void checkResize(final int minCapacity) {
+ if (minCapacity <= this.threshold || this.threshold < 0) {
+ return;
+ }
+
+ final TableEntry<V>[] table = this.getTablePlain();
+ int newCapacity = minCapacity >= MAXIMUM_CAPACITY ? MAXIMUM_CAPACITY : IntegerUtil.roundCeilLog2(minCapacity);
+ if (newCapacity < 0) {
+ newCapacity = MAXIMUM_CAPACITY;
+ }
+ if (newCapacity <= table.length) {
+ if (newCapacity == MAXIMUM_CAPACITY) {
+ return;
+ }
+ newCapacity = table.length << 1;
+ }
+
+ //noinspection unchecked
+ final TableEntry<V>[] newTable = new TableEntry[newCapacity];
+ final int indexMask = newCapacity - 1;
+
+ for (int i = 0, len = table.length; i < len; ++i) {
+ for (TableEntry<V> entry = table[i]; entry != null; entry = entry.getNextPlain()) {
+ final long key = entry.key;
+ final int hash = SWMRLong2ObjectHashTable.getHash(key);
+ final int index = hash & indexMask;
+
+ /* we need to create a new entry since there could be reading threads */
+ final TableEntry<V> insert = new TableEntry<>(key, entry.getValuePlain());
+
+ final TableEntry<V> prev = newTable[index];
+
+ newTable[index] = insert;
+ insert.setNextPlain(prev);
+ }
+ }
+
+ if (newCapacity == MAXIMUM_CAPACITY) {
+ this.threshold = -1; /* No more resizing */
+ } else {
+ this.threshold = getTargetCapacity(newCapacity, this.loadFactor);
+ }
+ this.setTableRelease(newTable); /* use release to publish entries in table */
+ }
+
+ protected final int addToSize(final int num) {
+ final int newSize = this.getSizePlain() + num;
+
+ this.setSizeOpaque(newSize);
+ this.checkResize(newSize);
+
+ return newSize;
+ }
+
+ protected final int removeFromSize(final int num) {
+ final int newSize = this.getSizePlain() - num;
+
+ this.setSizeOpaque(newSize);
+
+ return newSize;
+ }
+
+ protected final V put(final long key, final V value, final boolean onlyIfAbsent) {
+ final TableEntry<V>[] table = this.getTablePlain();
+ final int hash = SWMRLong2ObjectHashTable.getHash(key);
+ final int index = hash & (table.length - 1);
+
+ final TableEntry<V> head = table[index];
+ if (head == null) {
+ final TableEntry<V> insert = new TableEntry<>(key, value);
+ setAtIndexRelease(table, index, insert);
+ this.addToSize(1);
+ return null;
+ }
+
+ for (TableEntry<V> curr = head;;) {
+ if (key == curr.key) {
+ if (onlyIfAbsent) {
+ return curr.getValuePlain();
+ }
+
+ final V currVal = curr.getValuePlain();
+ curr.setValueRelease(value);
+ return currVal;
+ }
+
+ final TableEntry<V> next = curr.getNextPlain();
+ if (next != null) {
+ curr = next;
+ continue;
+ }
+
+ final TableEntry<V> insert = new TableEntry<>(key, value);
+
+ curr.setNextRelease(insert);
+ this.addToSize(1);
+ return null;
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public V put(final long key, final V value) {
+ Validate.notNull(value, "Null value");
+
+ return this.put(key, value, false);
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public V putIfAbsent(final long key, final V value) {
+ Validate.notNull(value, "Null value");
+
+ return this.put(key, value, true);
+ }
+
+ protected final V remove(final long key, final int hash) {
+ final TableEntry<V>[] table = this.getTablePlain();
+ final int index = (table.length - 1) & hash;
+
+ final TableEntry<V> head = table[index];
+ if (head == null) {
+ return null;
+ }
+
+ if (head.key == key) {
+ setAtIndexRelease(table, index, head.getNextPlain());
+ this.removeFromSize(1);
+
+ return head.getValuePlain();
+ }
+
+ for (TableEntry<V> curr = head.getNextPlain(), prev = head; curr != null; prev = curr, curr = curr.getNextPlain()) {
+ if (key == curr.key) {
+ prev.setNextRelease(curr.getNextPlain());
+ this.removeFromSize(1);
+
+ return curr.getValuePlain();
+ }
+ }
+
+ return null;
+ }
+
+ protected final V remove(final long key, final int hash, final V expect) {
+ final TableEntry<V>[] table = this.getTablePlain();
+ final int index = (table.length - 1) & hash;
+
+ final TableEntry<V> head = table[index];
+ if (head == null) {
+ return null;
+ }
+
+ if (head.key == key) {
+ final V val = head.value;
+ if (val == expect || val.equals(expect)) {
+ setAtIndexRelease(table, index, head.getNextPlain());
+ this.removeFromSize(1);
+
+ return head.getValuePlain();
+ } else {
+ return null;
+ }
+ }
+
+ for (TableEntry<V> curr = head.getNextPlain(), prev = head; curr != null; prev = curr, curr = curr.getNextPlain()) {
+ if (key == curr.key) {
+ final V val = curr.value;
+ if (val == expect || val.equals(expect)) {
+ prev.setNextRelease(curr.getNextPlain());
+ this.removeFromSize(1);
+
+ return curr.getValuePlain();
+ } else {
+ return null;
+ }
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public V remove(final long key) {
+ return this.remove(key, SWMRLong2ObjectHashTable.getHash(key));
+ }
+
+ public boolean remove(final long key, final V expect) {
+ return this.remove(key, SWMRLong2ObjectHashTable.getHash(key), expect) != null;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public void putAll(final SWMRLong2ObjectHashTable<? extends V> map) {
+ Validate.notNull(map, "Null map");
+
+ final int size = map.size();
+ this.checkResize(Math.max(this.getSizePlain() + size/2, size)); /* preemptively resize */
+ map.forEach(this::put);
+ }
+
+ /**
+ * {@inheritDoc}
+ * <p>
+ * This call is non-atomic and the order that which entries are removed is undefined. The clear operation itself
+ * is release ordered, that is, after the clear operation is performed a release fence is performed.
+ * </p>
+ */
+ public void clear() {
+ Arrays.fill(this.getTablePlain(), null);
+ this.setSizeRelease(0);
+ }
+
+ public static final class TableEntry<V> {
+
+ protected static final VarHandle TABLE_ENTRY_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(TableEntry[].class);
+
+ protected final long key;
+ protected V value;
+
+ protected TableEntry<V> next;
+
+ protected static final VarHandle VALUE_HANDLE = ConcurrentUtil.getVarHandle(TableEntry.class, "value", Object.class);
+ protected static final VarHandle NEXT_HANDLE = ConcurrentUtil.getVarHandle(TableEntry.class, "next", TableEntry.class);
+
+ /* value */
+
+ protected final V getValuePlain() {
+ //noinspection unchecked
+ return (V)VALUE_HANDLE.get(this);
+ }
+
+ protected final V getValueAcquire() {
+ //noinspection unchecked
+ return (V)VALUE_HANDLE.getAcquire(this);
+ }
+
+ protected final void setValueRelease(final V to) {
+ VALUE_HANDLE.setRelease(this, to);
+ }
+
+ /* next */
+
+ protected final TableEntry<V> getNextPlain() {
+ //noinspection unchecked
+ return (TableEntry<V>)NEXT_HANDLE.get(this);
+ }
+
+ protected final TableEntry<V> getNextOpaque() {
+ //noinspection unchecked
+ return (TableEntry<V>)NEXT_HANDLE.getOpaque(this);
+ }
+
+ protected final void setNextPlain(final TableEntry<V> next) {
+ NEXT_HANDLE.set(this, next);
+ }
+
+ protected final void setNextRelease(final TableEntry<V> next) {
+ NEXT_HANDLE.setRelease(this, next);
+ }
+
+ protected TableEntry(final long key, final V value) {
+ this.key = key;
+ this.value = value;
+ }
+
+ public long getKey() {
+ return this.key;
+ }
+
+ public V getValue() {
+ return this.getValueAcquire();
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/scheduler/SchedulerThreadPool.java b/src/main/java/ca/spottedleaf/concurrentutil/scheduler/SchedulerThreadPool.java
new file mode 100644
index 0000000000000000000000000000000000000000..8197ccb1c4e5878dbd8007b5fb514640765ec8e4
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/scheduler/SchedulerThreadPool.java
@@ -0,0 +1,558 @@
+package ca.spottedleaf.concurrentutil.scheduler;
+
+import ca.spottedleaf.concurrentutil.set.LinkedSortedSet;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import ca.spottedleaf.concurrentutil.util.TimeUtil;
+import java.lang.invoke.VarHandle;
+import java.util.BitSet;
+import java.util.Comparator;
+import java.util.PriorityQueue;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.LockSupport;
+import java.util.function.BooleanSupplier;
+
+public class SchedulerThreadPool {
+
+ public static final long DEADLINE_NOT_SET = Long.MIN_VALUE;
+
+ private static final Comparator<SchedulableTick> TICK_COMPARATOR_BY_TIME = (final SchedulableTick t1, final SchedulableTick t2) -> {
+ final int timeCompare = TimeUtil.compareTimes(t1.scheduledStart, t2.scheduledStart);
+ if (timeCompare != 0) {
+ return timeCompare;
+ }
+
+ return Long.compare(t1.id, t2.id);
+ };
+
+ private final TickThreadRunner[] runners;
+ private final Thread[] threads;
+ private final LinkedSortedSet<SchedulableTick> awaiting = new LinkedSortedSet<>(TICK_COMPARATOR_BY_TIME);
+ private final PriorityQueue<SchedulableTick> queued = new PriorityQueue<>(TICK_COMPARATOR_BY_TIME);
+ private final BitSet idleThreads;
+
+ private final Object scheduleLock = new Object();
+
+ private volatile boolean halted;
+
+ /**
+ * Creates, but does not start, a scheduler thread pool with the specified number of threads
+ * created using the specified thread factory.
+ * @param threads Specified number of threads
+ * @param threadFactory Specified thread factory
+ * @see #start()
+ */
+ public SchedulerThreadPool(final int threads, final ThreadFactory threadFactory) {
+ final BitSet idleThreads = new BitSet(threads);
+ for (int i = 0; i < threads; ++i) {
+ idleThreads.set(i);
+ }
+ this.idleThreads = idleThreads;
+
+ final TickThreadRunner[] runners = new TickThreadRunner[threads];
+ final Thread[] t = new Thread[threads];
+ for (int i = 0; i < threads; ++i) {
+ runners[i] = new TickThreadRunner(i, this);
+ t[i] = threadFactory.newThread(runners[i]);
+ }
+
+ this.threads = t;
+ this.runners = runners;
+ }
+
+ /**
+ * Starts the threads in this pool.
+ */
+ public void start() {
+ for (final Thread thread : this.threads) {
+ thread.start();
+ }
+ }
+
+ /**
+ * Attempts to prevent further execution of tasks, optionally waiting for the scheduler threads to die.
+ *
+ * @param sync Whether to wait for the scheduler threads to die.
+ * @param maxWaitNS The maximum time, in ns, to wait for the scheduler threads to die.
+ * @return {@code true} if sync was false, or if sync was true and the scheduler threads died before the timeout.
+ * Otherwise, returns {@code false} if the time elapsed exceeded the maximum wait time.
+ */
+ public boolean halt(final boolean sync, final long maxWaitNS) {
+ this.halted = true;
+ for (final Thread thread : this.threads) {
+ // force response to halt
+ LockSupport.unpark(thread);
+ }
+ final long time = System.nanoTime();
+ if (sync) {
+ // start at 10 * 0.5ms -> 5ms
+ for (long failures = 9L;; failures = ConcurrentUtil.linearLongBackoff(failures, 500_000L, 50_000_000L)) {
+ boolean allDead = true;
+ for (final Thread thread : this.threads) {
+ if (thread.isAlive()) {
+ allDead = false;
+ break;
+ }
+ }
+ if (allDead) {
+ return true;
+ }
+ if ((System.nanoTime() - time) >= maxWaitNS) {
+ return false;
+ }
+ }
+ }
+
+ return true;
+ }
+
+ /**
+ * Returns an array of the underlying scheduling threads.
+ */
+ public Thread[] getThreads() {
+ return this.threads.clone();
+ }
+
+ private void insertFresh(final SchedulableTick task) {
+ final TickThreadRunner[] runners = this.runners;
+
+ final int firstIdleThread = this.idleThreads.nextSetBit(0);
+
+ if (firstIdleThread != -1) {
+ // push to idle thread
+ this.idleThreads.clear(firstIdleThread);
+ final TickThreadRunner runner = runners[firstIdleThread];
+ task.awaitingLink = this.awaiting.addLast(task);
+ runner.acceptTask(task);
+ return;
+ }
+
+ // try to replace the last awaiting task
+ final SchedulableTick last = this.awaiting.last();
+
+ if (last != null && TICK_COMPARATOR_BY_TIME.compare(task, last) < 0) {
+ // need to replace the last task
+ this.awaiting.pollLast();
+ last.awaitingLink = null;
+ task.awaitingLink = this.awaiting.addLast(task);
+ // need to add task to queue to be picked up later
+ this.queued.add(last);
+
+ final TickThreadRunner runner = last.ownedBy;
+ runner.replaceTask(task);
+
+ return;
+ }
+
+ // add to queue, will be picked up later
+ this.queued.add(task);
+ }
+
+ private void takeTask(final TickThreadRunner runner, final SchedulableTick tick) {
+ if (!this.awaiting.remove(tick.awaitingLink)) {
+ throw new IllegalStateException("Task is not in awaiting");
+ }
+ tick.awaitingLink = null;
+ }
+
+ private SchedulableTick returnTask(final TickThreadRunner runner, final SchedulableTick reschedule) {
+ if (reschedule != null) {
+ this.queued.add(reschedule);
+ }
+ final SchedulableTick ret = this.queued.poll();
+ if (ret == null) {
+ this.idleThreads.set(runner.id);
+ } else {
+ ret.awaitingLink = this.awaiting.addLast(ret);
+ }
+
+ return ret;
+ }
+
+ /**
+ * Schedules the specified task to be executed on this thread pool.
+ * @param task Specified task
+ * @throws IllegalStateException If the task is already scheduled
+ * @see SchedulableTick
+ */
+ public void schedule(final SchedulableTick task) {
+ synchronized (this.scheduleLock) {
+ if (!task.tryMarkScheduled()) {
+ throw new IllegalStateException("Task " + task + " is already scheduled or cancelled");
+ }
+
+ task.schedulerOwnedBy = this;
+
+ this.insertFresh(task);
+ }
+ }
+
+ /**
+ * Updates the tasks scheduled start to the maximum of its current scheduled start and the specified
+ * new start. If the task is not scheduled, returns {@code false}. Otherwise, returns whether the
+ * scheduled start was updated. Undefined behavior of the specified task is scheduled in another executor.
+ * @param task Specified task
+ * @param newStart Specified new start
+ */
+ public boolean updateTickStartToMax(final SchedulableTick task, final long newStart) {
+ synchronized (this.scheduleLock) {
+ if (TimeUtil.compareTimes(newStart, task.getScheduledStart()) <= 0) {
+ return false;
+ }
+ if (this.queued.remove(task)) {
+ task.setScheduledStart(newStart);
+ this.queued.add(task);
+ return true;
+ }
+ if (task.awaitingLink != null) {
+ this.awaiting.remove(task.awaitingLink);
+ task.awaitingLink = null;
+
+ // re-queue task
+ task.setScheduledStart(newStart);
+ this.queued.add(task);
+
+ // now we need to replace the task the runner was waiting for
+ final TickThreadRunner runner = task.ownedBy;
+ final SchedulableTick replace = this.queued.poll();
+
+ // replace cannot be null, since we have added a task to queued
+ if (replace != task) {
+ runner.replaceTask(replace);
+ }
+
+ return true;
+ }
+
+ return false;
+ }
+ }
+
+ /**
+ * Returns {@code null} if the task is not scheduled, returns {@code TRUE} if the task was cancelled
+ * and was queued to execute, returns {@code FALSE} if the task was cancelled but was executing.
+ */
+ public Boolean tryRetire(final SchedulableTick task) {
+ if (task.schedulerOwnedBy != this) {
+ return null;
+ }
+
+ synchronized (this.scheduleLock) {
+ if (this.queued.remove(task)) {
+ // cancelled, and no runner owns it - so return
+ return Boolean.TRUE;
+ }
+ if (task.awaitingLink != null) {
+ this.awaiting.remove(task.awaitingLink);
+ task.awaitingLink = null;
+ // here we need to replace the task the runner was waiting for
+ final TickThreadRunner runner = task.ownedBy;
+ final SchedulableTick replace = this.queued.poll();
+
+ if (replace == null) {
+ // nothing to replace with, set to idle
+ this.idleThreads.set(runner.id);
+ runner.forceIdle();
+ } else {
+ runner.replaceTask(replace);
+ }
+
+ return Boolean.TRUE;
+ }
+
+ // could not find it in queue
+ return task.tryMarkCancelled() ? Boolean.FALSE : null;
+ }
+ }
+
+ /**
+ * Indicates that intermediate tasks are available to be executed by the task.
+ * <p>
+ * Note: currently a no-op
+ * </p>
+ * @param task The specified task
+ * @see SchedulableTick
+ */
+ public void notifyTasks(final SchedulableTick task) {
+ // Not implemented
+ }
+
+ /**
+ * Represents a tickable task that can be scheduled into a {@link SchedulerThreadPool}.
+ * <p>
+ * A tickable task is expected to run on a fixed interval, which is determined by
+ * the {@link SchedulerThreadPool}.
+ * </p>
+ * <p>
+ * A tickable task can have intermediate tasks that can be executed before its tick method is ran. Instead of
+ * the {@link SchedulerThreadPool} parking in-between ticks, the scheduler will instead drain
+ * intermediate tasks from scheduled tasks. The parsing of intermediate tasks allows the scheduler to take
+ * advantage of downtime to reduce the intermediate task load from tasks once they begin ticking.
+ * </p>
+ * <p>
+ * It is guaranteed that {@link #runTick()} and {@link #runTasks(BooleanSupplier)} are never
+ * invoked in parallel.
+ * It is required that when intermediate tasks are scheduled, that {@link SchedulerThreadPool#notifyTasks(SchedulableTick)}
+ * is invoked for any scheduled task - otherwise, {@link #runTasks(BooleanSupplier)} may not be invoked to
+ * parse intermediate tasks.
+ * </p>
+ */
+ public static abstract class SchedulableTick {
+ private static final AtomicLong ID_GENERATOR = new AtomicLong();
+ public final long id = ID_GENERATOR.getAndIncrement();
+
+ private static final int SCHEDULE_STATE_NOT_SCHEDULED = 0;
+ private static final int SCHEDULE_STATE_SCHEDULED = 1;
+ private static final int SCHEDULE_STATE_CANCELLED = 2;
+
+ private final AtomicInteger scheduled = new AtomicInteger();
+ private SchedulerThreadPool schedulerOwnedBy;
+ private long scheduledStart = DEADLINE_NOT_SET;
+ private TickThreadRunner ownedBy;
+
+ private LinkedSortedSet.Link<SchedulableTick> awaitingLink;
+
+ private boolean tryMarkScheduled() {
+ return this.scheduled.compareAndSet(SCHEDULE_STATE_NOT_SCHEDULED, SCHEDULE_STATE_SCHEDULED);
+ }
+
+ private boolean tryMarkCancelled() {
+ return this.scheduled.compareAndSet(SCHEDULE_STATE_SCHEDULED, SCHEDULE_STATE_CANCELLED);
+ }
+
+ private boolean isScheduled() {
+ return this.scheduled.get() == SCHEDULE_STATE_SCHEDULED;
+ }
+
+ protected final long getScheduledStart() {
+ return this.scheduledStart;
+ }
+
+ /**
+ * If this task is scheduled, then this may only be invoked during {@link #runTick()},
+ * and {@link #runTasks(BooleanSupplier)}
+ */
+ protected final void setScheduledStart(final long value) {
+ this.scheduledStart = value;
+ }
+
+ /**
+ * Executes the tick.
+ * <p>
+ * It is the callee's responsibility to invoke {@link #setScheduledStart(long)} to adjust the start of
+ * the next tick.
+ * </p>
+ * @return {@code true} if the task should continue to be scheduled, {@code false} otherwise.
+ */
+ public abstract boolean runTick();
+
+ /**
+ * Returns whether this task has any intermediate tasks that can be executed.
+ */
+ public abstract boolean hasTasks();
+
+ /**
+ * Returns {@code null} if this task should not be scheduled, otherwise returns
+ * {@code Boolean.TRUE} if there are more intermediate tasks to execute and
+ * {@code Boolean.FALSE} if there are no more intermediate tasks to execute.
+ */
+ public abstract Boolean runTasks(final BooleanSupplier canContinue);
+
+ @Override
+ public String toString() {
+ return "SchedulableTick:{" +
+ "class=" + this.getClass().getName() + "," +
+ "scheduled_state=" + this.scheduled.get() + ","
+ + "}";
+ }
+ }
+
+ private static final class TickThreadRunner implements Runnable {
+
+ /**
+ * There are no tasks in this thread's runqueue, so it is parked.
+ * <p>
+ * stateTarget = null
+ * </p>
+ */
+ private static final int STATE_IDLE = 0;
+
+ /**
+ * The runner is waiting to tick a task, as it has no intermediate tasks to execute.
+ * <p>
+ * stateTarget = the task awaiting tick
+ * </p>
+ */
+ private static final int STATE_AWAITING_TICK = 1;
+
+ /**
+ * The runner is executing a tick for one of the tasks that was in its runqueue.
+ * <p>
+ * stateTarget = the task being ticked
+ * </p>
+ */
+ private static final int STATE_EXECUTING_TICK = 2;
+
+ public final int id;
+ public final SchedulerThreadPool scheduler;
+
+ private volatile Thread thread;
+ private volatile TickThreadRunnerState state = new TickThreadRunnerState(null, STATE_IDLE);
+ private static final VarHandle STATE_HANDLE = ConcurrentUtil.getVarHandle(TickThreadRunner.class, "state", TickThreadRunnerState.class);
+
+ private void setStatePlain(final TickThreadRunnerState state) {
+ STATE_HANDLE.set(this, state);
+ }
+
+ private void setStateOpaque(final TickThreadRunnerState state) {
+ STATE_HANDLE.setOpaque(this, state);
+ }
+
+ private void setStateVolatile(final TickThreadRunnerState state) {
+ STATE_HANDLE.setVolatile(this, state);
+ }
+
+ private static record TickThreadRunnerState(SchedulableTick stateTarget, int state) {}
+
+ public TickThreadRunner(final int id, final SchedulerThreadPool scheduler) {
+ this.id = id;
+ this.scheduler = scheduler;
+ }
+
+ private Thread getRunnerThread() {
+ return this.thread;
+ }
+
+ private void acceptTask(final SchedulableTick task) {
+ if (task.ownedBy != null) {
+ throw new IllegalStateException("Already owned by another runner");
+ }
+ task.ownedBy = this;
+ final TickThreadRunnerState state = this.state;
+ if (state.state != STATE_IDLE) {
+ throw new IllegalStateException("Cannot accept task in state " + state);
+ }
+ this.setStateVolatile(new TickThreadRunnerState(task, STATE_AWAITING_TICK));
+ LockSupport.unpark(this.getRunnerThread());
+ }
+
+ private void replaceTask(final SchedulableTick task) {
+ final TickThreadRunnerState state = this.state;
+ if (state.state != STATE_AWAITING_TICK) {
+ throw new IllegalStateException("Cannot replace task in state " + state);
+ }
+ if (task.ownedBy != null) {
+ throw new IllegalStateException("Already owned by another runner");
+ }
+ task.ownedBy = this;
+
+ state.stateTarget.ownedBy = null;
+
+ this.setStateVolatile(new TickThreadRunnerState(task, STATE_AWAITING_TICK));
+ LockSupport.unpark(this.getRunnerThread());
+ }
+
+ private void forceIdle() {
+ final TickThreadRunnerState state = this.state;
+ if (state.state != STATE_AWAITING_TICK) {
+ throw new IllegalStateException("Cannot replace task in state " + state);
+ }
+ state.stateTarget.ownedBy = null;
+ this.setStateOpaque(new TickThreadRunnerState(null, STATE_IDLE));
+ // no need to unpark
+ }
+
+ private boolean takeTask(final TickThreadRunnerState state, final SchedulableTick task) {
+ synchronized (this.scheduler.scheduleLock) {
+ if (this.state != state) {
+ return false;
+ }
+ this.setStatePlain(new TickThreadRunnerState(task, STATE_EXECUTING_TICK));
+ this.scheduler.takeTask(this, task);
+ return true;
+ }
+ }
+
+ private void returnTask(final SchedulableTick task, final boolean reschedule) {
+ synchronized (this.scheduler.scheduleLock) {
+ task.ownedBy = null;
+
+ final SchedulableTick newWait = this.scheduler.returnTask(this, reschedule && task.isScheduled() ? task : null);
+ if (newWait == null) {
+ this.setStatePlain(new TickThreadRunnerState(null, STATE_IDLE));
+ } else {
+ if (newWait.ownedBy != null) {
+ throw new IllegalStateException("Already owned by another runner");
+ }
+ newWait.ownedBy = this;
+ this.setStatePlain(new TickThreadRunnerState(newWait, STATE_AWAITING_TICK));
+ }
+ }
+ }
+
+ @Override
+ public void run() {
+ this.thread = Thread.currentThread();
+
+ main_state_loop:
+ for (;;) {
+ final TickThreadRunnerState startState = this.state;
+ final int startStateType = startState.state;
+ final SchedulableTick startStateTask = startState.stateTarget;
+
+ if (this.scheduler.halted) {
+ return;
+ }
+
+ switch (startStateType) {
+ case STATE_IDLE: {
+ while (this.state.state == STATE_IDLE) {
+ LockSupport.park();
+ if (this.scheduler.halted) {
+ return;
+ }
+ }
+ continue main_state_loop;
+ }
+
+ case STATE_AWAITING_TICK: {
+ final long deadline = startStateTask.getScheduledStart();
+ for (;;) {
+ if (this.state != startState) {
+ continue main_state_loop;
+ }
+ final long diff = deadline - System.nanoTime();
+ if (diff <= 0L) {
+ break;
+ }
+ LockSupport.parkNanos(startState, diff);
+ if (this.scheduler.halted) {
+ return;
+ }
+ }
+
+ if (!this.takeTask(startState, startStateTask)) {
+ continue main_state_loop;
+ }
+
+ // TODO exception handling
+ final boolean reschedule = startStateTask.runTick();
+
+ this.returnTask(startStateTask, reschedule);
+
+ continue main_state_loop;
+ }
+
+ case STATE_EXECUTING_TICK: {
+ throw new IllegalStateException("Tick execution must be set by runner thread, not by any other thread");
+ }
+
+ default: {
+ throw new IllegalStateException("Unknown state: " + startState);
+ }
+ }
+ }
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/set/LinkedSortedSet.java b/src/main/java/ca/spottedleaf/concurrentutil/set/LinkedSortedSet.java
new file mode 100644
index 0000000000000000000000000000000000000000..212bc9ae2fc7d37d4a089a2921b00de1e97f7cc1
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/set/LinkedSortedSet.java
@@ -0,0 +1,272 @@
+package ca.spottedleaf.concurrentutil.set;
+
+import java.util.Comparator;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+public final class LinkedSortedSet<E> implements Iterable<E> {
+
+ public final Comparator<? super E> comparator;
+
+ protected Link<E> head;
+ protected Link<E> tail;
+
+ public LinkedSortedSet() {
+ this((Comparator)Comparator.naturalOrder());
+ }
+
+ public LinkedSortedSet(final Comparator<? super E> comparator) {
+ this.comparator = comparator;
+ }
+
+ public void clear() {
+ this.head = this.tail = null;
+ }
+
+ public boolean isEmpty() {
+ return this.head == null;
+ }
+
+ public E first() {
+ final Link<E> head = this.head;
+ return head == null ? null : head.element;
+ }
+
+ public E last() {
+ final Link<E> tail = this.tail;
+ return tail == null ? null : tail.element;
+ }
+
+ public boolean containsFirst(final E element) {
+ final Comparator<? super E> comparator = this.comparator;
+ for (Link<E> curr = this.head; curr != null; curr = curr.next) {
+ if (comparator.compare(element, curr.element) == 0) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ public boolean containsLast(final E element) {
+ final Comparator<? super E> comparator = this.comparator;
+ for (Link<E> curr = this.tail; curr != null; curr = curr.prev) {
+ if (comparator.compare(element, curr.element) == 0) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ private void removeNode(final Link<E> node) {
+ final Link<E> prev = node.prev;
+ final Link<E> next = node.next;
+
+ // help GC
+ node.element = null;
+ node.prev = null;
+ node.next = null;
+
+ if (prev == null) {
+ this.head = next;
+ } else {
+ prev.next = next;
+ }
+
+ if (next == null) {
+ this.tail = prev;
+ } else {
+ next.prev = prev;
+ }
+ }
+
+ public boolean remove(final Link<E> link) {
+ if (link.element == null) {
+ return false;
+ }
+
+ this.removeNode(link);
+ return true;
+ }
+
+ public boolean removeFirst(final E element) {
+ final Comparator<? super E> comparator = this.comparator;
+ for (Link<E> curr = this.head; curr != null; curr = curr.next) {
+ if (comparator.compare(element, curr.element) == 0) {
+ this.removeNode(curr);
+ return true;
+ }
+ }
+ return false;
+ }
+
+ public boolean removeLast(final E element) {
+ final Comparator<? super E> comparator = this.comparator;
+ for (Link<E> curr = this.tail; curr != null; curr = curr.prev) {
+ if (comparator.compare(element, curr.element) == 0) {
+ this.removeNode(curr);
+ return true;
+ }
+ }
+ return false;
+ }
+
+ @Override
+ public Iterator<E> iterator() {
+ return new Iterator<>() {
+ private Link<E> next = LinkedSortedSet.this.head;
+
+ @Override
+ public boolean hasNext() {
+ return this.next != null;
+ }
+
+ @Override
+ public E next() {
+ final Link<E> next = this.next;
+ if (next == null) {
+ throw new NoSuchElementException();
+ }
+ this.next = next.next;
+ return next.element;
+ }
+ };
+ }
+
+ public E pollFirst() {
+ final Link<E> head = this.head;
+ if (head == null) {
+ return null;
+ }
+
+ final E ret = head.element;
+ final Link<E> next = head.next;
+
+ // unlink head
+ this.head = next;
+ if (next == null) {
+ this.tail = null;
+ } else {
+ next.prev = null;
+ }
+
+ // help GC
+ head.element = null;
+ head.next = null;
+
+ return ret;
+ }
+
+ public E pollLast() {
+ final Link<E> tail = this.tail;
+ if (tail == null) {
+ return null;
+ }
+
+ final E ret = tail.element;
+ final Link<E> prev = tail.prev;
+
+ // unlink tail
+ this.tail = prev;
+ if (prev == null) {
+ this.head = null;
+ } else {
+ prev.next = null;
+ }
+
+ // help GC
+ tail.element = null;
+ tail.prev = null;
+
+ return ret;
+ }
+
+ public Link<E> addLast(final E element) {
+ final Comparator<? super E> comparator = this.comparator;
+
+ Link<E> curr = this.tail;
+ if (curr != null) {
+ int compare;
+
+ while ((compare = comparator.compare(element, curr.element)) < 0) {
+ Link<E> prev = curr;
+ curr = curr.prev;
+ if (curr != null) {
+ continue;
+ }
+ return this.head = prev.prev = new Link<>(element, null, prev);
+ }
+
+ if (compare != 0) {
+ // insert after curr
+ final Link<E> next = curr.next;
+ final Link<E> insert = new Link<>(element, curr, next);
+ curr.next = insert;
+
+ if (next == null) {
+ this.tail = insert;
+ } else {
+ next.prev = insert;
+ }
+ return insert;
+ }
+
+ return null;
+ } else {
+ return this.head = this.tail = new Link<>(element);
+ }
+ }
+
+ public Link<E> addFirst(final E element) {
+ final Comparator<? super E> comparator = this.comparator;
+
+ Link<E> curr = this.head;
+ if (curr != null) {
+ int compare;
+
+ while ((compare = comparator.compare(element, curr.element)) > 0) {
+ Link<E> prev = curr;
+ curr = curr.next;
+ if (curr != null) {
+ continue;
+ }
+ return this.tail = prev.next = new Link<>(element, prev, null);
+ }
+
+ if (compare != 0) {
+ // insert before curr
+ final Link<E> prev = curr.prev;
+ final Link<E> insert = new Link<>(element, prev, curr);
+ curr.prev = insert;
+
+ if (prev == null) {
+ this.head = insert;
+ } else {
+ prev.next = insert;
+ }
+ return insert;
+ }
+
+ return null;
+ } else {
+ return this.head = this.tail = new Link<>(element);
+ }
+ }
+
+ public static final class Link<E> {
+ private E element;
+ private Link<E> prev;
+ private Link<E> next;
+
+ private Link() {}
+
+ private Link(final E element) {
+ this.element = element;
+ }
+
+ private Link(final E element, final Link<E> prev, final Link<E> next) {
+ this.element = element;
+ this.prev = prev;
+ this.next = next;
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/ArrayUtil.java b/src/main/java/ca/spottedleaf/concurrentutil/util/ArrayUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..ebb1ab06165addb173fea4d295001fe37f4e79d3
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/ArrayUtil.java
@@ -0,0 +1,816 @@
+package ca.spottedleaf.concurrentutil.util;
+
+import java.lang.invoke.VarHandle;
+
+public final class ArrayUtil {
+
+ public static final VarHandle BOOLEAN_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(boolean[].class);
+
+ public static final VarHandle BYTE_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(byte[].class);
+
+ public static final VarHandle SHORT_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(short[].class);
+
+ public static final VarHandle INT_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(int[].class);
+
+ public static final VarHandle LONG_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(long[].class);
+
+ public static final VarHandle OBJECT_ARRAY_HANDLE = ConcurrentUtil.getArrayHandle(Object[].class);
+
+ private ArrayUtil() {
+ throw new RuntimeException();
+ }
+
+ /* byte array */
+
+ public static byte getPlain(final byte[] array, final int index) {
+ return (byte)BYTE_ARRAY_HANDLE.get(array, index);
+ }
+
+ public static byte getOpaque(final byte[] array, final int index) {
+ return (byte)BYTE_ARRAY_HANDLE.getOpaque(array, index);
+ }
+
+ public static byte getAcquire(final byte[] array, final int index) {
+ return (byte)BYTE_ARRAY_HANDLE.getAcquire(array, index);
+ }
+
+ public static byte getVolatile(final byte[] array, final int index) {
+ return (byte)BYTE_ARRAY_HANDLE.getVolatile(array, index);
+ }
+
+ public static void setPlain(final byte[] array, final int index, final byte value) {
+ BYTE_ARRAY_HANDLE.set(array, index, value);
+ }
+
+ public static void setOpaque(final byte[] array, final int index, final byte value) {
+ BYTE_ARRAY_HANDLE.setOpaque(array, index, value);
+ }
+
+ public static void setRelease(final byte[] array, final int index, final byte value) {
+ BYTE_ARRAY_HANDLE.setRelease(array, index, value);
+ }
+
+ public static void setVolatile(final byte[] array, final int index, final byte value) {
+ BYTE_ARRAY_HANDLE.setVolatile(array, index, value);
+ }
+
+ public static void setVolatileContended(final byte[] array, final int index, final byte param) {
+ int failures = 0;
+
+ for (byte curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return;
+ }
+ }
+ }
+
+ public static byte compareAndExchangeVolatile(final byte[] array, final int index, final byte expect, final byte update) {
+ return (byte)BYTE_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static byte getAndAddVolatile(final byte[] array, final int index, final byte param) {
+ return (byte)BYTE_ARRAY_HANDLE.getAndAdd(array, index, param);
+ }
+
+ public static byte getAndAndVolatile(final byte[] array, final int index, final byte param) {
+ return (byte)BYTE_ARRAY_HANDLE.getAndBitwiseAnd(array, index, param);
+ }
+
+ public static byte getAndOrVolatile(final byte[] array, final int index, final byte param) {
+ return (byte)BYTE_ARRAY_HANDLE.getAndBitwiseOr(array, index, param);
+ }
+
+ public static byte getAndXorVolatile(final byte[] array, final int index, final byte param) {
+ return (byte)BYTE_ARRAY_HANDLE.getAndBitwiseXor(array, index, param);
+ }
+
+ public static byte getAndSetVolatile(final byte[] array, final int index, final byte param) {
+ return (byte)BYTE_ARRAY_HANDLE.getAndSet(array, index, param);
+ }
+
+ public static byte compareAndExchangeVolatileContended(final byte[] array, final int index, final byte expect, final byte update) {
+ return (byte)BYTE_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static byte getAndAddVolatileContended(final byte[] array, final int index, final byte param) {
+ int failures = 0;
+
+ for (byte curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (byte) (curr + param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static byte getAndAndVolatileContended(final byte[] array, final int index, final byte param) {
+ int failures = 0;
+
+ for (byte curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (byte) (curr & param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static byte getAndOrVolatileContended(final byte[] array, final int index, final byte param) {
+ int failures = 0;
+
+ for (byte curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (byte) (curr | param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static byte getAndXorVolatileContended(final byte[] array, final int index, final byte param) {
+ int failures = 0;
+
+ for (byte curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (byte) (curr ^ param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static byte getAndSetVolatileContended(final byte[] array, final int index, final byte param) {
+ int failures = 0;
+
+ for (byte curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return curr;
+ }
+ }
+ }
+
+ /* short array */
+
+ public static short getPlain(final short[] array, final int index) {
+ return (short)SHORT_ARRAY_HANDLE.get(array, index);
+ }
+
+ public static short getOpaque(final short[] array, final int index) {
+ return (short)SHORT_ARRAY_HANDLE.getOpaque(array, index);
+ }
+
+ public static short getAcquire(final short[] array, final int index) {
+ return (short)SHORT_ARRAY_HANDLE.getAcquire(array, index);
+ }
+
+ public static short getVolatile(final short[] array, final int index) {
+ return (short)SHORT_ARRAY_HANDLE.getVolatile(array, index);
+ }
+
+ public static void setPlain(final short[] array, final int index, final short value) {
+ SHORT_ARRAY_HANDLE.set(array, index, value);
+ }
+
+ public static void setOpaque(final short[] array, final int index, final short value) {
+ SHORT_ARRAY_HANDLE.setOpaque(array, index, value);
+ }
+
+ public static void setRelease(final short[] array, final int index, final short value) {
+ SHORT_ARRAY_HANDLE.setRelease(array, index, value);
+ }
+
+ public static void setVolatile(final short[] array, final int index, final short value) {
+ SHORT_ARRAY_HANDLE.setVolatile(array, index, value);
+ }
+
+ public static void setVolatileContended(final short[] array, final int index, final short param) {
+ int failures = 0;
+
+ for (short curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return;
+ }
+ }
+ }
+
+ public static short compareAndExchangeVolatile(final short[] array, final int index, final short expect, final short update) {
+ return (short)SHORT_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static short getAndAddVolatile(final short[] array, final int index, final short param) {
+ return (short)SHORT_ARRAY_HANDLE.getAndAdd(array, index, param);
+ }
+
+ public static short getAndAndVolatile(final short[] array, final int index, final short param) {
+ return (short)SHORT_ARRAY_HANDLE.getAndBitwiseAnd(array, index, param);
+ }
+
+ public static short getAndOrVolatile(final short[] array, final int index, final short param) {
+ return (short)SHORT_ARRAY_HANDLE.getAndBitwiseOr(array, index, param);
+ }
+
+ public static short getAndXorVolatile(final short[] array, final int index, final short param) {
+ return (short)SHORT_ARRAY_HANDLE.getAndBitwiseXor(array, index, param);
+ }
+
+ public static short getAndSetVolatile(final short[] array, final int index, final short param) {
+ return (short)SHORT_ARRAY_HANDLE.getAndSet(array, index, param);
+ }
+
+ public static short compareAndExchangeVolatileContended(final short[] array, final int index, final short expect, final short update) {
+ return (short)SHORT_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static short getAndAddVolatileContended(final short[] array, final int index, final short param) {
+ int failures = 0;
+
+ for (short curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (short) (curr + param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static short getAndAndVolatileContended(final short[] array, final int index, final short param) {
+ int failures = 0;
+
+ for (short curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (short) (curr & param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static short getAndOrVolatileContended(final short[] array, final int index, final short param) {
+ int failures = 0;
+
+ for (short curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (short) (curr | param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static short getAndXorVolatileContended(final short[] array, final int index, final short param) {
+ int failures = 0;
+
+ for (short curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (short) (curr ^ param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static short getAndSetVolatileContended(final short[] array, final int index, final short param) {
+ int failures = 0;
+
+ for (short curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return curr;
+ }
+ }
+ }
+
+ /* int array */
+
+ public static int getPlain(final int[] array, final int index) {
+ return (int)INT_ARRAY_HANDLE.get(array, index);
+ }
+
+ public static int getOpaque(final int[] array, final int index) {
+ return (int)INT_ARRAY_HANDLE.getOpaque(array, index);
+ }
+
+ public static int getAcquire(final int[] array, final int index) {
+ return (int)INT_ARRAY_HANDLE.getAcquire(array, index);
+ }
+
+ public static int getVolatile(final int[] array, final int index) {
+ return (int)INT_ARRAY_HANDLE.getVolatile(array, index);
+ }
+
+ public static void setPlain(final int[] array, final int index, final int value) {
+ INT_ARRAY_HANDLE.set(array, index, value);
+ }
+
+ public static void setOpaque(final int[] array, final int index, final int value) {
+ INT_ARRAY_HANDLE.setOpaque(array, index, value);
+ }
+
+ public static void setRelease(final int[] array, final int index, final int value) {
+ INT_ARRAY_HANDLE.setRelease(array, index, value);
+ }
+
+ public static void setVolatile(final int[] array, final int index, final int value) {
+ INT_ARRAY_HANDLE.setVolatile(array, index, value);
+ }
+
+ public static void setVolatileContended(final int[] array, final int index, final int param) {
+ int failures = 0;
+
+ for (int curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return;
+ }
+ }
+ }
+
+ public static int compareAndExchangeVolatile(final int[] array, final int index, final int expect, final int update) {
+ return (int)INT_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static int getAndAddVolatile(final int[] array, final int index, final int param) {
+ return (int)INT_ARRAY_HANDLE.getAndAdd(array, index, param);
+ }
+
+ public static int getAndAndVolatile(final int[] array, final int index, final int param) {
+ return (int)INT_ARRAY_HANDLE.getAndBitwiseAnd(array, index, param);
+ }
+
+ public static int getAndOrVolatile(final int[] array, final int index, final int param) {
+ return (int)INT_ARRAY_HANDLE.getAndBitwiseOr(array, index, param);
+ }
+
+ public static int getAndXorVolatile(final int[] array, final int index, final int param) {
+ return (int)INT_ARRAY_HANDLE.getAndBitwiseXor(array, index, param);
+ }
+
+ public static int getAndSetVolatile(final int[] array, final int index, final int param) {
+ return (int)INT_ARRAY_HANDLE.getAndSet(array, index, param);
+ }
+
+ public static int compareAndExchangeVolatileContended(final int[] array, final int index, final int expect, final int update) {
+ return (int)INT_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static int getAndAddVolatileContended(final int[] array, final int index, final int param) {
+ int failures = 0;
+
+ for (int curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (int) (curr + param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static int getAndAndVolatileContended(final int[] array, final int index, final int param) {
+ int failures = 0;
+
+ for (int curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (int) (curr & param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static int getAndOrVolatileContended(final int[] array, final int index, final int param) {
+ int failures = 0;
+
+ for (int curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (int) (curr | param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static int getAndXorVolatileContended(final int[] array, final int index, final int param) {
+ int failures = 0;
+
+ for (int curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (int) (curr ^ param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static int getAndSetVolatileContended(final int[] array, final int index, final int param) {
+ int failures = 0;
+
+ for (int curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return curr;
+ }
+ }
+ }
+
+ /* long array */
+
+ public static long getPlain(final long[] array, final int index) {
+ return (long)LONG_ARRAY_HANDLE.get(array, index);
+ }
+
+ public static long getOpaque(final long[] array, final int index) {
+ return (long)LONG_ARRAY_HANDLE.getOpaque(array, index);
+ }
+
+ public static long getAcquire(final long[] array, final int index) {
+ return (long)LONG_ARRAY_HANDLE.getAcquire(array, index);
+ }
+
+ public static long getVolatile(final long[] array, final int index) {
+ return (long)LONG_ARRAY_HANDLE.getVolatile(array, index);
+ }
+
+ public static void setPlain(final long[] array, final int index, final long value) {
+ LONG_ARRAY_HANDLE.set(array, index, value);
+ }
+
+ public static void setOpaque(final long[] array, final int index, final long value) {
+ LONG_ARRAY_HANDLE.setOpaque(array, index, value);
+ }
+
+ public static void setRelease(final long[] array, final int index, final long value) {
+ LONG_ARRAY_HANDLE.setRelease(array, index, value);
+ }
+
+ public static void setVolatile(final long[] array, final int index, final long value) {
+ LONG_ARRAY_HANDLE.setVolatile(array, index, value);
+ }
+
+ public static void setVolatileContended(final long[] array, final int index, final long param) {
+ int failures = 0;
+
+ for (long curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return;
+ }
+ }
+ }
+
+ public static long compareAndExchangeVolatile(final long[] array, final int index, final long expect, final long update) {
+ return (long)LONG_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static long getAndAddVolatile(final long[] array, final int index, final long param) {
+ return (long)LONG_ARRAY_HANDLE.getAndAdd(array, index, param);
+ }
+
+ public static long getAndAndVolatile(final long[] array, final int index, final long param) {
+ return (long)LONG_ARRAY_HANDLE.getAndBitwiseAnd(array, index, param);
+ }
+
+ public static long getAndOrVolatile(final long[] array, final int index, final long param) {
+ return (long)LONG_ARRAY_HANDLE.getAndBitwiseOr(array, index, param);
+ }
+
+ public static long getAndXorVolatile(final long[] array, final int index, final long param) {
+ return (long)LONG_ARRAY_HANDLE.getAndBitwiseXor(array, index, param);
+ }
+
+ public static long getAndSetVolatile(final long[] array, final int index, final long param) {
+ return (long)LONG_ARRAY_HANDLE.getAndSet(array, index, param);
+ }
+
+ public static long compareAndExchangeVolatileContended(final long[] array, final int index, final long expect, final long update) {
+ return (long)LONG_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static long getAndAddVolatileContended(final long[] array, final int index, final long param) {
+ int failures = 0;
+
+ for (long curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (long) (curr + param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static long getAndAndVolatileContended(final long[] array, final int index, final long param) {
+ int failures = 0;
+
+ for (long curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (long) (curr & param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static long getAndOrVolatileContended(final long[] array, final int index, final long param) {
+ int failures = 0;
+
+ for (long curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (long) (curr | param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static long getAndXorVolatileContended(final long[] array, final int index, final long param) {
+ int failures = 0;
+
+ for (long curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (long) (curr ^ param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static long getAndSetVolatileContended(final long[] array, final int index, final long param) {
+ int failures = 0;
+
+ for (long curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return curr;
+ }
+ }
+ }
+
+ /* boolean array */
+
+ public static boolean getPlain(final boolean[] array, final int index) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.get(array, index);
+ }
+
+ public static boolean getOpaque(final boolean[] array, final int index) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.getOpaque(array, index);
+ }
+
+ public static boolean getAcquire(final boolean[] array, final int index) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.getAcquire(array, index);
+ }
+
+ public static boolean getVolatile(final boolean[] array, final int index) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.getVolatile(array, index);
+ }
+
+ public static void setPlain(final boolean[] array, final int index, final boolean value) {
+ BOOLEAN_ARRAY_HANDLE.set(array, index, value);
+ }
+
+ public static void setOpaque(final boolean[] array, final int index, final boolean value) {
+ BOOLEAN_ARRAY_HANDLE.setOpaque(array, index, value);
+ }
+
+ public static void setRelease(final boolean[] array, final int index, final boolean value) {
+ BOOLEAN_ARRAY_HANDLE.setRelease(array, index, value);
+ }
+
+ public static void setVolatile(final boolean[] array, final int index, final boolean value) {
+ BOOLEAN_ARRAY_HANDLE.setVolatile(array, index, value);
+ }
+
+ public static void setVolatileContended(final boolean[] array, final int index, final boolean param) {
+ int failures = 0;
+
+ for (boolean curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return;
+ }
+ }
+ }
+
+ public static boolean compareAndExchangeVolatile(final boolean[] array, final int index, final boolean expect, final boolean update) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static boolean getAndOrVolatile(final boolean[] array, final int index, final boolean param) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.getAndBitwiseOr(array, index, param);
+ }
+
+ public static boolean getAndXorVolatile(final boolean[] array, final int index, final boolean param) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.getAndBitwiseXor(array, index, param);
+ }
+
+ public static boolean getAndSetVolatile(final boolean[] array, final int index, final boolean param) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.getAndSet(array, index, param);
+ }
+
+ public static boolean compareAndExchangeVolatileContended(final boolean[] array, final int index, final boolean expect, final boolean update) {
+ return (boolean)BOOLEAN_ARRAY_HANDLE.compareAndExchange(array, index, expect, update);
+ }
+
+ public static boolean getAndAndVolatileContended(final boolean[] array, final int index, final boolean param) {
+ int failures = 0;
+
+ for (boolean curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (boolean) (curr & param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static boolean getAndOrVolatileContended(final boolean[] array, final int index, final boolean param) {
+ int failures = 0;
+
+ for (boolean curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (boolean) (curr | param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static boolean getAndXorVolatileContended(final boolean[] array, final int index, final boolean param) {
+ int failures = 0;
+
+ for (boolean curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, (boolean) (curr ^ param)))) {
+ return curr;
+ }
+ }
+ }
+
+ public static boolean getAndSetVolatileContended(final boolean[] array, final int index, final boolean param) {
+ int failures = 0;
+
+ for (boolean curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return curr;
+ }
+ }
+ }
+
+ @SuppressWarnings("unchecked")
+ public static <T> T getPlain(final T[] array, final int index) {
+ final Object ret = OBJECT_ARRAY_HANDLE.get((Object[])array, index);
+ return (T)ret;
+ }
+
+ @SuppressWarnings("unchecked")
+ public static <T> T getOpaque(final T[] array, final int index) {
+ final Object ret = OBJECT_ARRAY_HANDLE.getOpaque((Object[])array, index);
+ return (T)ret;
+ }
+
+ @SuppressWarnings("unchecked")
+ public static <T> T getAcquire(final T[] array, final int index) {
+ final Object ret = OBJECT_ARRAY_HANDLE.getAcquire((Object[])array, index);
+ return (T)ret;
+ }
+
+ @SuppressWarnings("unchecked")
+ public static <T> T getVolatile(final T[] array, final int index) {
+ final Object ret = OBJECT_ARRAY_HANDLE.getVolatile((Object[])array, index);
+ return (T)ret;
+ }
+
+ public static <T> void setPlain(final T[] array, final int index, final T value) {
+ OBJECT_ARRAY_HANDLE.set((Object[])array, index, (Object)value);
+ }
+
+ public static <T> void setOpaque(final T[] array, final int index, final T value) {
+ OBJECT_ARRAY_HANDLE.setOpaque((Object[])array, index, (Object)value);
+ }
+
+ public static <T> void setRelease(final T[] array, final int index, final T value) {
+ OBJECT_ARRAY_HANDLE.setRelease((Object[])array, index, (Object)value);
+ }
+
+ public static <T> void setVolatile(final T[] array, final int index, final T value) {
+ OBJECT_ARRAY_HANDLE.setVolatile((Object[])array, index, (Object)value);
+ }
+
+ public static <T> void setVolatileContended(final T[] array, final int index, final T param) {
+ int failures = 0;
+
+ for (T curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return;
+ }
+ }
+ }
+
+ @SuppressWarnings("unchecked")
+ public static <T> T compareAndExchangeVolatile(final T[] array, final int index, final T expect, final T update) {
+ final Object ret = OBJECT_ARRAY_HANDLE.compareAndExchange((Object[])array, index, (Object)expect, (Object)update);
+ return (T)ret;
+ }
+
+ @SuppressWarnings("unchecked")
+ public static <T> T getAndSetVolatile(final T[] array, final int index, final T param) {
+ final Object ret = BYTE_ARRAY_HANDLE.getAndSet((Object[])array, index, (Object)param);
+ return (T)ret;
+ }
+
+ @SuppressWarnings("unchecked")
+ public static <T> T compareAndExchangeVolatileContended(final T[] array, final int index, final T expect, final T update) {
+ final Object ret = OBJECT_ARRAY_HANDLE.compareAndExchange((Object[])array, index, (Object)expect, (Object)update);
+ return (T)ret;
+ }
+
+ public static <T> T getAndSetVolatileContended(final T[] array, final int index, final T param) {
+ int failures = 0;
+
+ for (T curr = getVolatile(array, index);;++failures) {
+ for (int i = 0; i < failures; ++i) {
+ ConcurrentUtil.backoff();
+ }
+
+ if (curr == (curr = compareAndExchangeVolatileContended(array, index, curr, param))) {
+ return curr;
+ }
+ }
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/CollectionUtil.java b/src/main/java/ca/spottedleaf/concurrentutil/util/CollectionUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..9420b9822de99d3a31224642452835b0c986f7b4
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/CollectionUtil.java
@@ -0,0 +1,31 @@
+package ca.spottedleaf.concurrentutil.util;
+
+import java.util.Collection;
+
+public final class CollectionUtil {
+
+ public static String toString(final Collection<?> collection, final String name) {
+ return CollectionUtil.toString(collection, name, new StringBuilder(name.length() + 128)).toString();
+ }
+
+ public static StringBuilder toString(final Collection<?> collection, final String name, final StringBuilder builder) {
+ builder.append(name).append("{elements={");
+
+ boolean first = true;
+
+ for (final Object element : collection) {
+ if (!first) {
+ builder.append(", ");
+ }
+ first = false;
+
+ builder.append('"').append(element).append('"');
+ }
+
+ return builder.append("}}");
+ }
+
+ private CollectionUtil() {
+ throw new RuntimeException();
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/ConcurrentUtil.java b/src/main/java/ca/spottedleaf/concurrentutil/util/ConcurrentUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..23ae82e55696a7e2ff0e0f9609c0df6a48bb8d1d
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/ConcurrentUtil.java
@@ -0,0 +1,166 @@
+package ca.spottedleaf.concurrentutil.util;
+
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+import java.util.concurrent.locks.LockSupport;
+
+public final class ConcurrentUtil {
+
+ public static String genericToString(final Object object) {
+ return object == null ? "null" : object.getClass().getName() + ":" + object.hashCode() + ":" + object.toString();
+ }
+
+ public static void rethrow(Throwable exception) {
+ rethrow0(exception);
+ }
+
+ private static <T extends Throwable> void rethrow0(Throwable thr) throws T {
+ throw (T)thr;
+ }
+
+ public static VarHandle getVarHandle(final Class<?> lookIn, final String fieldName, final Class<?> fieldType) {
+ try {
+ return MethodHandles.privateLookupIn(lookIn, MethodHandles.lookup()).findVarHandle(lookIn, fieldName, fieldType);
+ } catch (final Exception ex) {
+ throw new RuntimeException(ex); // unreachable
+ }
+ }
+
+ public static VarHandle getStaticVarHandle(final Class<?> lookIn, final String fieldName, final Class<?> fieldType) {
+ try {
+ return MethodHandles.privateLookupIn(lookIn, MethodHandles.lookup()).findStaticVarHandle(lookIn, fieldName, fieldType);
+ } catch (final Exception ex) {
+ throw new RuntimeException(ex); // unreachable
+ }
+ }
+
+ /**
+ * Non-exponential backoff algorithm to use in lightly contended areas.
+ * @see ConcurrentUtil#exponentiallyBackoffSimple(long)
+ * @see ConcurrentUtil#exponentiallyBackoffComplex(long)
+ */
+ public static void backoff() {
+ Thread.onSpinWait();
+ }
+
+ /**
+ * Backoff algorithm to use for a short held lock (i.e compareAndExchange operation). Generally this should not be
+ * used when a thread can block another thread. Instead, use {@link ConcurrentUtil#exponentiallyBackoffComplex(long)}.
+ * @param counter The current counter.
+ * @return The counter plus 1.
+ * @see ConcurrentUtil#backoff()
+ * @see ConcurrentUtil#exponentiallyBackoffComplex(long)
+ */
+ public static long exponentiallyBackoffSimple(final long counter) {
+ for (long i = 0; i < counter; ++i) {
+ backoff();
+ }
+ return counter + 1L;
+ }
+
+ /**
+ * Backoff algorithm to use for a lock that can block other threads (i.e if another thread contending with this thread
+ * can be thrown off the scheduler). This lock should not be used for simple locks such as compareAndExchange.
+ * @param counter The current counter.
+ * @return The next (if any) step in the backoff logic.
+ * @see ConcurrentUtil#backoff()
+ * @see ConcurrentUtil#exponentiallyBackoffSimple(long)
+ */
+ public static long exponentiallyBackoffComplex(final long counter) {
+ // TODO experimentally determine counters
+ if (counter < 100L) {
+ return exponentiallyBackoffSimple(counter);
+ }
+ if (counter < 1_200L) {
+ Thread.yield();
+ LockSupport.parkNanos(1_000L);
+ return counter + 1L;
+ }
+ // scale 0.1ms (100us) per failure
+ Thread.yield();
+ LockSupport.parkNanos(100_000L * counter);
+ return counter + 1;
+ }
+
+ /**
+ * Simple exponential backoff that will linearly increase the time per failure, according to the scale.
+ * @param counter The current failure counter.
+ * @param scale Time per failure, in ns.
+ * @param max The maximum time to wait for, in ns.
+ * @return The next counter.
+ */
+ public static long linearLongBackoff(long counter, final long scale, long max) {
+ counter = Math.min(Long.MAX_VALUE, counter + 1); // prevent overflow
+ max = Math.max(0, max);
+
+ if (scale <= 0L) {
+ return counter;
+ }
+
+ long time = scale * counter;
+
+ if (time > max || time / scale != counter) {
+ time = max;
+ }
+
+ boolean interrupted = Thread.interrupted();
+ if (time > 1_000_000L) { // 1ms
+ Thread.yield();
+ }
+ LockSupport.parkNanos(time);
+ if (interrupted) {
+ Thread.currentThread().interrupt();
+ }
+ return counter;
+ }
+
+ /**
+ * Simple exponential backoff that will linearly increase the time per failure, according to the scale.
+ * @param counter The current failure counter.
+ * @param scale Time per failure, in ns.
+ * @param max The maximum time to wait for, in ns.
+ * @param deadline The deadline in ns. Deadline time source: {@link System#nanoTime()}.
+ * @return The next counter.
+ */
+ public static long linearLongBackoffDeadline(long counter, final long scale, long max, long deadline) {
+ counter = Math.min(Long.MAX_VALUE, counter + 1); // prevent overflow
+ max = Math.max(0, max);
+
+ if (scale <= 0L) {
+ return counter;
+ }
+
+ long time = scale * counter;
+
+ // check overflow
+ if (time / scale != counter) {
+ // overflew
+ --counter;
+ time = max;
+ } else if (time > max) {
+ time = max;
+ }
+
+ final long currTime = System.nanoTime();
+ final long diff = deadline - currTime;
+ if (diff <= 0) {
+ return counter;
+ }
+ if (diff <= 1_500_000L) { // 1.5ms
+ time = 100_000L; // 100us
+ } else if (time > 1_000_000L) { // 1ms
+ Thread.yield();
+ }
+
+ boolean interrupted = Thread.interrupted();
+ LockSupport.parkNanos(time);
+ if (interrupted) {
+ Thread.currentThread().interrupt();
+ }
+ return counter;
+ }
+
+ public static VarHandle getArrayHandle(final Class<?> type) {
+ return MethodHandles.arrayElementVarHandle(type);
+ }
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/HashUtil.java b/src/main/java/ca/spottedleaf/concurrentutil/util/HashUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..2b9f36211d1cbb4fcf1457c0a83592499e9aa23b
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/HashUtil.java
@@ -0,0 +1,111 @@
+package ca.spottedleaf.concurrentutil.util;
+
+public final class HashUtil {
+
+ // Copied from fastutil HashCommon
+
+ /** 2<sup>32</sup> · φ, φ = (√5 − 1)/2. */
+ private static final int INT_PHI = 0x9E3779B9;
+ /** The reciprocal of {@link #INT_PHI} modulo 2<sup>32</sup>. */
+ private static final int INV_INT_PHI = 0x144cbc89;
+ /** 2<sup>64</sup> · φ, φ = (√5 − 1)/2. */
+ private static final long LONG_PHI = 0x9E3779B97F4A7C15L;
+ /** The reciprocal of {@link #LONG_PHI} modulo 2<sup>64</sup>. */
+ private static final long INV_LONG_PHI = 0xf1de83e19937733dL;
+
+ /** Avalanches the bits of an integer by applying the finalisation step of MurmurHash3.
+ *
+ * <p>This method implements the finalisation step of Austin Appleby's <a href="http://code.google.com/p/smhasher/">MurmurHash3</a>.
+ * Its purpose is to avalanche the bits of the argument to within 0.25% bias.
+ *
+ * @param x an integer.
+ * @return a hash value with good avalanching properties.
+ */
+ // additional note: this function is a bijection onto all integers
+ public static int murmurHash3(int x) {
+ x ^= x >>> 16;
+ x *= 0x85ebca6b;
+ x ^= x >>> 13;
+ x *= 0xc2b2ae35;
+ x ^= x >>> 16;
+ return x;
+ }
+
+
+ /** Avalanches the bits of a long integer by applying the finalisation step of MurmurHash3.
+ *
+ * <p>This method implements the finalisation step of Austin Appleby's <a href="http://code.google.com/p/smhasher/">MurmurHash3</a>.
+ * Its purpose is to avalanche the bits of the argument to within 0.25% bias.
+ *
+ * @param x a long integer.
+ * @return a hash value with good avalanching properties.
+ */
+ // additional note: this function is a bijection onto all longs
+ public static long murmurHash3(long x) {
+ x ^= x >>> 33;
+ x *= 0xff51afd7ed558ccdL;
+ x ^= x >>> 33;
+ x *= 0xc4ceb9fe1a85ec53L;
+ x ^= x >>> 33;
+ return x;
+ }
+
+ /** Quickly mixes the bits of an integer.
+ *
+ * <p>This method mixes the bits of the argument by multiplying by the golden ratio and
+ * xorshifting the result. It is borrowed from <a href="https://github.com/leventov/Koloboke">Koloboke</a>, and
+ * it has slightly worse behaviour than {@link #murmurHash3(int)} (in open-addressing hash tables the average number of probes
+ * is slightly larger), but it's much faster.
+ *
+ * @param x an integer.
+ * @return a hash value obtained by mixing the bits of {@code x}.
+ * @see #invMix(int)
+ */
+ // additional note: this function is a bijection onto all integers
+ public static int mix(final int x) {
+ final int h = x * INT_PHI;
+ return h ^ (h >>> 16);
+ }
+
+ /** The inverse of {@link #mix(int)}. This method is mainly useful to create unit tests.
+ *
+ * @param x an integer.
+ * @return a value that passed through {@link #mix(int)} would give {@code x}.
+ */
+ // additional note: this function is a bijection onto all integers
+ public static int invMix(final int x) {
+ return (x ^ x >>> 16) * INV_INT_PHI;
+ }
+
+ /** Quickly mixes the bits of a long integer.
+ *
+ * <p>This method mixes the bits of the argument by multiplying by the golden ratio and
+ * xorshifting twice the result. It is borrowed from <a href="https://github.com/leventov/Koloboke">Koloboke</a>, and
+ * it has slightly worse behaviour than {@link #murmurHash3(long)} (in open-addressing hash tables the average number of probes
+ * is slightly larger), but it's much faster.
+ *
+ * @param x a long integer.
+ * @return a hash value obtained by mixing the bits of {@code x}.
+ */
+ // additional note: this function is a bijection onto all longs
+ public static long mix(final long x) {
+ long h = x * LONG_PHI;
+ h ^= h >>> 32;
+ return h ^ (h >>> 16);
+ }
+
+ /** The inverse of {@link #mix(long)}. This method is mainly useful to create unit tests.
+ *
+ * @param x a long integer.
+ * @return a value that passed through {@link #mix(long)} would give {@code x}.
+ */
+ // additional note: this function is a bijection onto all longs
+ public static long invMix(long x) {
+ x ^= x >>> 32;
+ x ^= x >>> 16;
+ return (x ^ x >>> 32) * INV_LONG_PHI;
+ }
+
+
+ private HashUtil() {}
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/IntPairUtil.java b/src/main/java/ca/spottedleaf/concurrentutil/util/IntPairUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..4e61c477a56e645228d5a2015c26816954d17bf8
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/IntPairUtil.java
@@ -0,0 +1,46 @@
+package ca.spottedleaf.concurrentutil.util;
+
+public final class IntPairUtil {
+
+ /**
+ * Packs the specified integers into one long value.
+ */
+ public static long key(final int left, final int right) {
+ return ((long)right << 32) | (left & 0xFFFFFFFFL);
+ }
+
+ /**
+ * Retrieves the left packed integer from the key
+ */
+ public static int left(final long key) {
+ return (int)key;
+ }
+
+ /**
+ * Retrieves the right packed integer from the key
+ */
+ public static int right(final long key) {
+ return (int)(key >>> 32);
+ }
+
+ public static String toString(final long key) {
+ return "{left:" + left(key) + ", right:" + right(key) + "}";
+ }
+
+ public static String toString(final long[] array, final int from, final int to) {
+ final StringBuilder ret = new StringBuilder();
+ ret.append("[");
+
+ for (int i = from; i < to; ++i) {
+ if (i != from) {
+ ret.append(", ");
+ }
+ ret.append(toString(array[i]));
+ }
+
+ ret.append("]");
+ return ret.toString();
+ }
+
+ private IntPairUtil() {}
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/IntegerUtil.java b/src/main/java/ca/spottedleaf/concurrentutil/util/IntegerUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..77699c5fa9681f9ec7aa05cbb50eb60828e193ab
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/IntegerUtil.java
@@ -0,0 +1,176 @@
+package ca.spottedleaf.concurrentutil.util;
+
+public final class IntegerUtil {
+
+ public static final int HIGH_BIT_U32 = Integer.MIN_VALUE;
+ public static final long HIGH_BIT_U64 = Long.MIN_VALUE;
+
+ public static int ceilLog2(final int value) {
+ return Integer.SIZE - Integer.numberOfLeadingZeros(value - 1); // see doc of numberOfLeadingZeros
+ }
+
+ public static long ceilLog2(final long value) {
+ return Long.SIZE - Long.numberOfLeadingZeros(value - 1); // see doc of numberOfLeadingZeros
+ }
+
+ public static int floorLog2(final int value) {
+ // xor is optimized subtract for 2^n -1
+ // note that (2^n -1) - k = (2^n -1) ^ k for k <= (2^n - 1)
+ return (Integer.SIZE - 1) ^ Integer.numberOfLeadingZeros(value); // see doc of numberOfLeadingZeros
+ }
+
+ public static int floorLog2(final long value) {
+ // xor is optimized subtract for 2^n -1
+ // note that (2^n -1) - k = (2^n -1) ^ k for k <= (2^n - 1)
+ return (Long.SIZE - 1) ^ Long.numberOfLeadingZeros(value); // see doc of numberOfLeadingZeros
+ }
+
+ public static int roundCeilLog2(final int value) {
+ // optimized variant of 1 << (32 - leading(val - 1))
+ // given
+ // 1 << n = HIGH_BIT_32 >>> (31 - n) for n [0, 32)
+ // 1 << (32 - leading(val - 1)) = HIGH_BIT_32 >>> (31 - (32 - leading(val - 1)))
+ // HIGH_BIT_32 >>> (31 - (32 - leading(val - 1)))
+ // HIGH_BIT_32 >>> (31 - 32 + leading(val - 1))
+ // HIGH_BIT_32 >>> (-1 + leading(val - 1))
+ return HIGH_BIT_U32 >>> (Integer.numberOfLeadingZeros(value - 1) - 1);
+ }
+
+ public static long roundCeilLog2(final long value) {
+ // see logic documented above
+ return HIGH_BIT_U64 >>> (Long.numberOfLeadingZeros(value - 1) - 1);
+ }
+
+ public static int roundFloorLog2(final int value) {
+ // optimized variant of 1 << (31 - leading(val))
+ // given
+ // 1 << n = HIGH_BIT_32 >>> (31 - n) for n [0, 32)
+ // 1 << (31 - leading(val)) = HIGH_BIT_32 >> (31 - (31 - leading(val)))
+ // HIGH_BIT_32 >> (31 - (31 - leading(val)))
+ // HIGH_BIT_32 >> (31 - 31 + leading(val))
+ return HIGH_BIT_U32 >>> Integer.numberOfLeadingZeros(value);
+ }
+
+ public static long roundFloorLog2(final long value) {
+ // see logic documented above
+ return HIGH_BIT_U64 >>> Long.numberOfLeadingZeros(value);
+ }
+
+ public static boolean isPowerOfTwo(final int n) {
+ // 2^n has one bit
+ // note: this rets true for 0 still
+ return IntegerUtil.getTrailingBit(n) == n;
+ }
+
+ public static boolean isPowerOfTwo(final long n) {
+ // 2^n has one bit
+ // note: this rets true for 0 still
+ return IntegerUtil.getTrailingBit(n) == n;
+ }
+
+ public static int getTrailingBit(final int n) {
+ return -n & n;
+ }
+
+ public static long getTrailingBit(final long n) {
+ return -n & n;
+ }
+
+ public static int trailingZeros(final int n) {
+ return Integer.numberOfTrailingZeros(n);
+ }
+
+ public static int trailingZeros(final long n) {
+ return Long.numberOfTrailingZeros(n);
+ }
+
+ // from hacker's delight (signed division magic value)
+ public static int getDivisorMultiple(final long numbers) {
+ return (int)(numbers >>> 32);
+ }
+
+ // from hacker's delight (signed division magic value)
+ public static int getDivisorShift(final long numbers) {
+ return (int)numbers;
+ }
+
+ // copied from hacker's delight (signed division magic value)
+ // http://www.hackersdelight.org/hdcodetxt/magic.c.txt
+ public static long getDivisorNumbers(final int d) {
+ final int ad = branchlessAbs(d);
+
+ if (ad < 2) {
+ throw new IllegalArgumentException("|number| must be in [2, 2^31 -1], not: " + d);
+ }
+
+ final int two31 = 0x80000000;
+ final long mask = 0xFFFFFFFFL; // mask for enforcing unsigned behaviour
+
+ /*
+ Signed usage:
+ int number;
+ long magic = getDivisorNumbers(div);
+ long mul = magic >>> 32;
+ int sign = number >> 31;
+ int result = (int)(((long)number * mul) >>> magic) - sign;
+ */
+ /*
+ Unsigned usage: (note: fails for input > Integer.MAX_VALUE, only use when input < Integer.MAX_VALUE to avoid sign calculation)
+ int number;
+ long magic = getDivisorNumbers(div);
+ long mul = magic >>> 32;
+ int result = (int)(((long)number * mul) >>> magic);
+ */
+
+ int p = 31;
+
+ // all these variables are UNSIGNED!
+ int t = two31 + (d >>> 31);
+ int anc = t - 1 - (int)((t & mask)%ad);
+ int q1 = (int)((two31 & mask)/(anc & mask));
+ int r1 = two31 - q1*anc;
+ int q2 = (int)((two31 & mask)/(ad & mask));
+ int r2 = two31 - q2*ad;
+ int delta;
+
+ do {
+ p = p + 1;
+ q1 = 2*q1; // Update q1 = 2**p/|nc|.
+ r1 = 2*r1; // Update r1 = rem(2**p, |nc|).
+ if ((r1 & mask) >= (anc & mask)) {// (Must be an unsigned comparison here)
+ q1 = q1 + 1;
+ r1 = r1 - anc;
+ }
+ q2 = 2*q2; // Update q2 = 2**p/|d|.
+ r2 = 2*r2; // Update r2 = rem(2**p, |d|).
+ if ((r2 & mask) >= (ad & mask)) {// (Must be an unsigned comparison here)
+ q2 = q2 + 1;
+ r2 = r2 - ad;
+ }
+ delta = ad - r2;
+ } while ((q1 & mask) < (delta & mask) || (q1 == delta && r1 == 0));
+
+ int magicNum = q2 + 1;
+ if (d < 0) {
+ magicNum = -magicNum;
+ }
+ int shift = p;
+ return ((long)magicNum << 32) | shift;
+ }
+
+ public static int branchlessAbs(final int val) {
+ // -n = -1 ^ n + 1
+ final int mask = val >> (Integer.SIZE - 1); // -1 if < 0, 0 if >= 0
+ return (mask ^ val) - mask; // if val < 0, then (0 ^ val) - 0 else (-1 ^ val) + 1
+ }
+
+ public static long branchlessAbs(final long val) {
+ // -n = -1 ^ n + 1
+ final long mask = val >> (Long.SIZE - 1); // -1 if < 0, 0 if >= 0
+ return (mask ^ val) - mask; // if val < 0, then (0 ^ val) - 0 else (-1 ^ val) + 1
+ }
+
+ private IntegerUtil() {
+ throw new RuntimeException();
+ }
+}
\ No newline at end of file
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/ThrowUtil.java b/src/main/java/ca/spottedleaf/concurrentutil/util/ThrowUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..a3a8b5c6795c4d116e094e4c910553416f565b93
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/ThrowUtil.java
@@ -0,0 +1,11 @@
+package ca.spottedleaf.concurrentutil.util;
+
+public final class ThrowUtil {
+
+ private ThrowUtil() {}
+
+ public static <T extends Throwable> void throwUnchecked(final Throwable thr) throws T {
+ throw (T)thr;
+ }
+
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/TimeUtil.java b/src/main/java/ca/spottedleaf/concurrentutil/util/TimeUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..63688716244066581d5b505703576e3340e3baf3
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/TimeUtil.java
@@ -0,0 +1,60 @@
+package ca.spottedleaf.concurrentutil.util;
+
+public final class TimeUtil {
+
+ /*
+ * The comparator is not a valid comparator for every long value. To prove where it is valid, see below.
+ *
+ * For reflexivity, we have that x - x = 0. We then have that for any long value x that
+ * compareTimes(x, x) == 0, as expected.
+ *
+ * For symmetry, we have that x - y = -(y - x) except for when y - x = Long.MIN_VALUE.
+ * So, the difference between any times x and y must not be equal to Long.MIN_VALUE.
+ *
+ * As for the transitive relation, consider we have x,y such that x - y = a > 0 and z such that
+ * y - z = b > 0. Then, we will have that the x - z > 0 is equivalent to a + b > 0. For long values,
+ * this holds as long as a + b <= Long.MAX_VALUE.
+ *
+ * Also consider we have x, y such that x - y = a < 0 and z such that y - z = b < 0. Then, we will have
+ * that x - z < 0 is equivalent to a + b < 0. For long values, this holds as long as a + b >= -Long.MAX_VALUE.
+ *
+ * Thus, the comparator is only valid for timestamps such that abs(c - d) <= Long.MAX_VALUE for all timestamps
+ * c and d.
+ */
+
+ /**
+ * This function is appropriate to be used as a {@link java.util.Comparator} between two timestamps, which
+ * indicates whether the timestamps represented by t1, t2 that t1 is before, equal to, or after t2.
+ */
+ public static int compareTimes(final long t1, final long t2) {
+ final long diff = t1 - t2;
+
+ // HD, Section 2-7
+ return (int) ((diff >> 63) | (-diff >>> 63));
+ }
+
+ public static long getGreatestTime(final long t1, final long t2) {
+ final long diff = t1 - t2;
+ return diff < 0L ? t2 : t1;
+ }
+
+ public static long getLeastTime(final long t1, final long t2) {
+ final long diff = t1 - t2;
+ return diff > 0L ? t2 : t1;
+ }
+
+ public static long clampTime(final long value, final long min, final long max) {
+ final long diffMax = value - max;
+ final long diffMin = value - min;
+
+ if (diffMax > 0L) {
+ return max;
+ }
+ if (diffMin < 0L) {
+ return min;
+ }
+ return value;
+ }
+
+ private TimeUtil() {}
+}
diff --git a/src/main/java/ca/spottedleaf/concurrentutil/util/Validate.java b/src/main/java/ca/spottedleaf/concurrentutil/util/Validate.java
new file mode 100644
index 0000000000000000000000000000000000000000..382177d0d162fa3139c9078a873ce2504a2b17b2
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/util/Validate.java
@@ -0,0 +1,28 @@
+package ca.spottedleaf.concurrentutil.util;
+
+public final class Validate {
+
+ public static <T> T notNull(final T obj) {
+ if (obj == null) {
+ throw new NullPointerException();
+ }
+ return obj;
+ }
+
+ public static <T> T notNull(final T obj, final String msgIfNull) {
+ if (obj == null) {
+ throw new NullPointerException(msgIfNull);
+ }
+ return obj;
+ }
+
+ public static void arrayBounds(final int off, final int len, final int arrayLength, final String msgPrefix) {
+ if (off < 0 || len < 0 || (arrayLength - off) < len) {
+ throw new ArrayIndexOutOfBoundsException(msgPrefix + ": off: " + off + ", len: " + len + ", array length: " + arrayLength);
+ }
+ }
+
+ private Validate() {
+ throw new RuntimeException();
+ }
+}