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..f4415f782b32fed25da98e44b172f717c4d46e34
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/collection/MultiThreadedQueue.java
@@ -0,0 +1,1402 @@
+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;
+                }
+            }
+        }
+    }
+
+    /**
+     * 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..597659f38aa816646dcda4ca39c002b6d9f9a792
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/collection/SRSWLinkedQueue.java
@@ -0,0 +1,148 @@
+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..a1ad3308f9c3545a604b635896259a1cd3382b2a
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/completable/Completable.java
@@ -0,0 +1,98 @@
+package ca.spottedleaf.concurrentutil.completable;
+
+import ca.spottedleaf.concurrentutil.collection.MultiThreadedQueue;
+import ca.spottedleaf.concurrentutil.executor.Cancellable;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
+import java.util.function.BiConsumer;
+
+public final class Completable<T> {
+
+    private static final Logger LOGGER = LogUtils.getLogger();
+
+    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;
+    }
+
+    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);
+        }
+    }
+
+    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..8c452b0988da4725762d543f6bee09915c328ae6
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/BaseExecutor.java
@@ -0,0 +1,198 @@
+package ca.spottedleaf.concurrentutil.executor;
+
+import ca.spottedleaf.concurrentutil.executor.standard.PrioritisedExecutor;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import java.util.function.BooleanSupplier;
+
+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 cal.
+     * </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.
+     * <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
+     */
+    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}.
+     */
+    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) && !condition.getAsBoolean() && (System.nanoTime() < deadline)) {
+            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}.
+     */
+    public default void executeUntil(final long deadline) {
+        long failures = 0;
+        while (System.nanoTime() < deadline) {
+            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
+     */
+    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 of the tasks scheduled have been executed.
+     * @return Returns whether this queue has shut down.
+     */
+    public default boolean isShutdown() {
+        return false;
+    }
+
+    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..e5d8ff730ba9d83efc2d80782de313a718bf55b3
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedExecutor.java
@@ -0,0 +1,246 @@
+package ca.spottedleaf.concurrentutil.executor.standard;
+
+import ca.spottedleaf.concurrentutil.executor.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 PrioritisedExecutor.Priority max(final Priority p1, final Priority p2) {
+            return p1.isHigherOrEqualPriority(p2) ? p1 : p2;
+        }
+
+        // returns the lower priroity of the two
+        public static PrioritisedExecutor.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 PrioritisedExecutor.Priority[] PRIORITIES = PrioritisedExecutor.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 PrioritisedExecutor.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;
+        }
+    }
+
+    /**
+     * 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, PrioritisedExecutor.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 PrioritisedExecutor.Priority priority);
+
+    /**
+     * Creates, but does not execute or queue the task. The task must later be queued via {@link BaseExecutor.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 PrioritisedExecutor.PrioritisedTask createTask(final Runnable task) {
+        return this.createTask(task, PrioritisedExecutor.Priority.NORMAL);
+    }
+
+    /**
+     * Creates, but does not execute or queue the task. The task must later be queued via {@link BaseExecutor.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 PrioritisedExecutor.PrioritisedTask createTask(final Runnable task, final PrioritisedExecutor.Priority priority);
+
+    public static interface PrioritisedTask extends BaseTask {
+
+        /**
+         * Returns the current priority. Note that {@link PrioritisedExecutor.Priority#COMPLETING} will be returned
+         * if this task is completing or has completed.
+         */
+        public PrioritisedExecutor.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 PrioritisedExecutor.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 PrioritisedExecutor.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 PrioritisedExecutor.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..91fe0f7049122f62f05ba09c24cba5d758340cff
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedQueueExecutorThread.java
@@ -0,0 +1,297 @@
+package ca.spottedleaf.concurrentutil.executor.standard;
+
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
+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 = LogUtils.getLogger();
+
+    protected final PrioritisedExecutor queue;
+
+    protected volatile boolean threadShutdown;
+
+    protected static final VarHandle THREAD_PARKED_HANDLE = ConcurrentUtil.getVarHandle(PrioritisedQueueExecutorThread.class, "threadParked", boolean.class);
+    protected volatile boolean threadParked;
+
+    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");
+            }
+        }
+    }
+
+    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 PrioritisedExecutor.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 PrioritisedExecutor.PrioritisedTask queueRunnable(final Runnable task, final PrioritisedExecutor.Priority priority) {
+        final PrioritisedExecutor.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..26fa2caa18a9194e57574a4a7fa9f7a4265740e0
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/executor/standard/PrioritisedThreadPool.java
@@ -0,0 +1,579 @@
+package ca.spottedleaf.concurrentutil.executor.standard;
+
+import com.mojang.logging.LogUtils;
+import it.unimi.dsi.fastutil.objects.ReferenceOpenHashSet;
+import org.slf4j.Logger;
+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 = LogUtils.getLogger();
+
+    protected final PrioritisedThread[] threads;
+    protected final TreeSet<PrioritisedPoolExecutorImpl> queues = new TreeSet<>(PrioritisedPoolExecutorImpl.comparator());
+    protected final String name;
+    protected final long queueMaxHoldTime;
+
+    protected final ReferenceOpenHashSet<PrioritisedPoolExecutorImpl> nonShutdownQueues = new ReferenceOpenHashSet<>();
+    protected final ReferenceOpenHashSet<PrioritisedPoolExecutorImpl> activeQueues = new ReferenceOpenHashSet<>();
+
+    protected boolean shutdown;
+
+    protected long schedulingIdGenerator;
+
+    protected static final long DEFAULT_QUEUE_HOLD_TIME = (long)(5.0e6);
+
+    public PrioritisedThreadPool(final String name, final int threads) {
+        this(name, threads, null);
+    }
+
+    public PrioritisedThreadPool(final String name, final int threads, final BiConsumer<Thread, Integer> threadModifier) {
+        this(name, threads, threadModifier, DEFAULT_QUEUE_HOLD_TIME); // 5ms
+    }
+
+    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();
+        }
+    }
+
+    public Thread[] getThreads() {
+        return Arrays.copyOf(this.threads, this.threads.length, Thread[].class);
+    }
+
+    public PrioritisedPoolExecutor createExecutor(final String name, 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));
+
+            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();
+            }
+        }
+    }
+
+    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 boolean isQueued;
+
+        public PrioritisedPoolExecutorImpl(final PrioritisedThreadPool pool, final String name, final int maximumExecutors) {
+            this.pool = pool;
+            this.name = name;
+            this.maximumExecutors = maximumExecutors;
+        }
+
+        public static Comparator<PrioritisedPoolExecutorImpl> comparator() {
+            return (final PrioritisedPoolExecutorImpl p1, final PrioritisedPoolExecutorImpl p2) -> {
+                if (p1 == p2) {
+                    return 0;
+                }
+
+                // 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..b71404be2c82f7db35272b367af861e94d6c73d3
--- /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 PrioritisedExecutor.Priority priority) throws IllegalStateException, IllegalArgumentException {
+        if (!PrioritisedExecutor.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 (!PrioritisedExecutor.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 PrioritisedExecutor.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 PrioritisedExecutor.Priority priority;
+
+        protected PrioritisedTask(final long id, final Runnable runnable, final PrioritisedExecutor.Priority priority, final PrioritisedThreadedTaskQueue queue) {
+            if (!PrioritisedExecutor.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 PrioritisedExecutor.Priority priority, final PrioritisedThreadedTaskQueue queue) {
+            if (!PrioritisedExecutor.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 PrioritisedExecutor.Priority priority = this.priority;
+                if (priority == PrioritisedExecutor.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 PrioritisedExecutor.Priority oldPriority = this.priority;
+            if (oldPriority != PrioritisedExecutor.Priority.COMPLETING && oldPriority.isHigherOrEqualPriority(minPriority)) {
+                this.priority = PrioritisedExecutor.Priority.COMPLETING;
+                if (this.id != NOT_SCHEDULED_ID) {
+                    this.queue.priorityChange(this, oldPriority, PrioritisedExecutor.Priority.COMPLETING);
+                }
+                return true;
+            }
+
+            return false;
+        }
+
+        @Override
+        public PrioritisedExecutor.Priority getPriority() {
+            return this.priority;
+        }
+
+        @Override
+        public boolean setPriority(final PrioritisedExecutor.Priority priority) {
+            if (!PrioritisedExecutor.Priority.isValidPriority(priority)) {
+                throw new IllegalArgumentException("Invalid priority " + priority);
+            }
+            synchronized (this.queue.queues) {
+                final PrioritisedExecutor.Priority curr = this.priority;
+
+                if (curr == PrioritisedExecutor.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 PrioritisedExecutor.Priority priority) {
+            if (!PrioritisedExecutor.Priority.isValidPriority(priority)) {
+                throw new IllegalArgumentException("Invalid priority " + priority);
+            }
+
+            synchronized (this.queue.queues) {
+                final PrioritisedExecutor.Priority curr = this.priority;
+
+                if (curr == PrioritisedExecutor.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 PrioritisedExecutor.Priority priority) {
+            if (!PrioritisedExecutor.Priority.isValidPriority(priority)) {
+                throw new IllegalArgumentException("Invalid priority " + priority);
+            }
+
+            synchronized (this.queue.queues) {
+                final PrioritisedExecutor.Priority curr = this.priority;
+
+                if (curr == PrioritisedExecutor.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 == PrioritisedExecutor.Priority.COMPLETING) {
+                    return false;
+                }
+
+                this.priority = PrioritisedExecutor.Priority.COMPLETING;
+                // call priority change callback
+                if ((id = this.id) != NOT_SCHEDULED_ID) {
+                    this.queue.priorityChange(this, oldPriority, PrioritisedExecutor.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 == PrioritisedExecutor.Priority.COMPLETING) {
+                    return false;
+                }
+
+                this.priority = PrioritisedExecutor.Priority.COMPLETING;
+                // call priority change callback
+                if (this.id != NOT_SCHEDULED_ID) {
+                    this.queue.priorityChange(this, oldPriority, PrioritisedExecutor.Priority.COMPLETING);
+                }
+            }
+
+            this.executeInternal();
+            return true;
+        }
+    }
+}
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..4289b984badd6f9167c86193454a630b9a40f9f5
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/map/SWMRHashTable.java
@@ -0,0 +1,1673 @@
+package ca.spottedleaf.concurrentutil.map;
+
+import ca.spottedleaf.concurrentutil.util.ArrayUtil;
+import ca.spottedleaf.concurrentutil.util.CollectionUtil;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import ca.spottedleaf.concurrentutil.util.Validate;
+import io.papermc.paper.util.IntegerUtil;
+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 and 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 and 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);
+    }
+
+    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 = ArrayUtil.getOpaque(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();
+        // inlined IntegerUtil#hash0
+        hash *= 0x36935555;
+        hash ^= hash >>> 16;
+        return hash;
+    }
+
+    static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
+    static final int spread(int h) {
+        return (h ^ (h >>> 16)) & HASH_BITS;
+    }
+
+    // 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)) {
+            return false;
+        }
+        final Map<?, ?> other = (Map<?, ?>)obj;
+
+        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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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 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<Entry<K, V>> iterator() {
+        return new EntryIterator<>(this.getTableAcquire(), this);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void forEach(final Consumer<? super 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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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 Set<K> keyset;
+    protected Collection<V> values;
+    protected Set<Map.Entry<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);
+            ArrayUtil.setRelease(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 */
+
+                ArrayUtil.setRelease(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 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 */
+
+                ArrayUtil.setRelease(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;
+            }
+
+            ArrayUtil.setRelease(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))) {
+            ArrayUtil.setRelease(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) {
+                    ArrayUtil.setRelease(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) {
+                    ArrayUtil.setRelease(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) {
+                ArrayUtil.setRelease(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) {
+                ArrayUtil.setRelease(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) {
+                    ArrayUtil.setRelease(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) {
+                    ArrayUtil.setRelease(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 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;
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        @Override
+        public K getKey() {
+            return this.key;
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        @Override
+        public V getValue() {
+            return this.getValueAcquire();
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        @Override
+        public V setValue(final V value) {
+            if (value == null) {
+                throw new NullPointerException();
+            }
+
+            final V curr = this.getValuePlain();
+
+            this.setValueRelease(value);
+            return curr;
+        }
+
+        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)) {
+                return false;
+            }
+            final Map.Entry<?, ?> other = (Map.Entry<?, ?>)obj;
+            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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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<?, ?>)) {
+                return false;
+            }
+            final Map.Entry<?, ?> entry = (Map.Entry<?, ?>)object;
+
+            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<Entry<K, V>> iterator() {
+            return new EntryIterator<>(this.map.getTableAcquire(), this.map);
+        }
+
+        @Override
+        public void forEach(final Consumer<? super Entry<K, V>> action) {
+            this.map.forEach(action);
+        }
+
+        @Override
+        public boolean contains(final Object object) {
+            if (!(object instanceof Map.Entry)) {
+                return false;
+            }
+            final Map.Entry<?, ?> entry = (Map.Entry<?, ?>)object;
+
+            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..94fca3c9b31ca4e40688209e419e93320b0f7c34
--- /dev/null
+++ b/src/main/java/ca/spottedleaf/concurrentutil/map/SWMRLong2ObjectHashTable.java
@@ -0,0 +1,672 @@
+package ca.spottedleaf.concurrentutil.map;
+
+import ca.spottedleaf.concurrentutil.util.ArrayUtil;
+import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
+import ca.spottedleaf.concurrentutil.util.Validate;
+import io.papermc.paper.util.IntegerUtil;
+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 and 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 and 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);
+    }
+
+    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 = ArrayUtil.getOpaque(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)it.unimi.dsi.fastutil.HashCommon.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)) {
+            return false;
+        }
+        final SWMRLong2ObjectHashTable<?> other = (SWMRLong2ObjectHashTable<?>)obj;
+
+        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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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 SWMRLong2ObjectHashTable.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 = ArrayUtil.getOpaque(table, i); curr != null; curr = curr.getNextOpaque()) {
+                action.accept(curr);
+            }
+        }
+    }
+
+    @FunctionalInterface
+    public static interface BiLongObjectConsumer<V> {
+        public void accept(final long key, final V value);
+    }
+
+    /**
+     * {@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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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 = ArrayUtil.getOpaque(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);
+            ArrayUtil.setRelease(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) {
+            ArrayUtil.setRelease(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;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public V remove(final long key) {
+        return this.remove(key, SWMRLong2ObjectHashTable.getHash(key));
+    }
+
+    /**
+     * {@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 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();
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public V setValue(final V value) {
+            if (value == null) {
+                throw new NullPointerException();
+            }
+
+            final V curr = this.getValuePlain();
+
+            this.setValueRelease(value);
+            return curr;
+        }
+
+        protected static int hash(final long key, final Object value) {
+            return SWMRLong2ObjectHashTable.getHash(key) ^ (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 TableEntry<?>)) {
+                return false;
+            }
+            final TableEntry<?> other = (TableEntry<?>)obj;
+            final long otherKey = other.getKey();
+            final long thisKey = this.getKey();
+            final Object otherValue = other.getValueAcquire();
+            final V thisVal = this.getValueAcquire();
+            return (thisKey == otherKey) && (thisVal == otherValue || thisVal.equals(otherValue));
+        }
+    }
+}
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/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();
+    }
+}
