From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Martijn Muijsers <martijnmuijsers@live.nl>
Date: Sun, 11 Dec 2022 16:24:15 +0100
Subject: [PATCH] FIFO concurrent queue utility

License: AGPL-3.0 (https://www.gnu.org/licenses/agpl-3.0.html)
Gale - https://galemc.org

diff --git a/src/main/java/org/galemc/gale/collection/FIFOConcurrentLinkedQueue.java b/src/main/java/org/galemc/gale/collection/FIFOConcurrentLinkedQueue.java
new file mode 100644
index 0000000000000000000000000000000000000000..010035d51ceba9ec59821a95386c54a324e715b5
--- /dev/null
+++ b/src/main/java/org/galemc/gale/collection/FIFOConcurrentLinkedQueue.java
@@ -0,0 +1,133 @@
+// Gale - FIFO concurrent queue utility
+
+package org.galemc.gale.collection;
+
+import org.galemc.gale.executor.annotation.AnyThreadSafe;
+import org.galemc.gale.executor.annotation.YieldFree;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedDeque;
+import java.util.concurrent.ConcurrentLinkedQueue;
+
+/**
+ * A utility class that implements the {@link Queue} interface, and provides an identical implementation to
+ * {@link ConcurrentLinkedQueue}, except for adding elements, which appends the given element to the front (head)
+ * instead of the back (tail) of this queue.
+ *
+ * @author Martijn Muijsers under AGPL-3.0
+ */
+@AnyThreadSafe @YieldFree
+public class FIFOConcurrentLinkedQueue<E> implements Queue<E> {
+
+    private final ConcurrentLinkedDeque<E> deque;
+
+    public FIFOConcurrentLinkedQueue() {
+        this.deque = new ConcurrentLinkedDeque<>();
+    }
+
+    public FIFOConcurrentLinkedQueue(Collection<? extends E> c) {
+        this.deque = new ConcurrentLinkedDeque<>(c);
+    }
+
+    @Override
+    public int size() {
+        return this.deque.size();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return this.deque.isEmpty();
+    }
+
+    @Override
+    public boolean contains(Object o) {
+        return this.deque.contains(o);
+    }
+
+    @NotNull
+    @Override
+    public Iterator<E> iterator() {
+        return this.deque.iterator();
+    }
+
+    @NotNull
+    @Override
+    public Object[] toArray() {
+        return this.deque.toArray();
+    }
+
+    @NotNull
+    @Override
+    public <T> T[] toArray(@NotNull T[] ts) {
+        return this.deque.toArray(ts);
+    }
+
+    @Override
+    public boolean add(E e) {
+        this.deque.addFirst(e);
+        return true;
+    }
+
+    @Override
+    public boolean remove(Object o) {
+        return this.deque.remove(o);
+    }
+
+    @Override
+    public boolean containsAll(@NotNull Collection<?> collection) {
+        return this.deque.containsAll(collection);
+    }
+
+    @Override
+    public boolean addAll(@NotNull Collection<? extends E> collection) {
+        boolean changed = false;
+        for (E element : collection) {
+            changed |= this.add(element);
+        }
+        return changed;
+    }
+
+    @Override
+    public boolean removeAll(@NotNull Collection<?> collection) {
+        return this.deque.removeAll(collection);
+    }
+
+    @Override
+    public boolean retainAll(@NotNull Collection<?> collection) {
+        return this.deque.retainAll(collection);
+    }
+
+    @Override
+    public void clear() {
+        this.deque.clear();
+    }
+
+    @Override
+    public boolean offer(E e) {
+        return this.deque.offer(e);
+    }
+
+    @Override
+    public E remove() {
+        return this.deque.remove();
+    }
+
+    @Override
+    public E poll() {
+        return this.deque.poll();
+    }
+
+    @Override
+    public E element() {
+        return this.deque.element();
+    }
+
+    @Override
+    public E peek() {
+        return this.deque.peek();
+    }
+
+}