Adding java.util.Queue interface and java.util.AbstractQueue.

classpath/java/util/AbstractQueue.java

@@ -0,0 +1,60 @@
+/* Copyright (c) 2012, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.util;
+
+public abstract class AbstractQueue<T> extends AbstractCollection<T> implements Queue<T> {
+  
+  protected AbstractQueue() {
+    super();
+  }
+  
+  public boolean add(T element) {
+    if (offer(element)) {
+      return true;
+    } else {
+      throw new IllegalStateException();
+    }
+  }
+  
+  public boolean addAll(Collection <? extends T> collection) {
+    if (collection == null) {
+      throw new NullPointerException();
+    }
+
+    for (T element : collection) {
+      add(element);
+    }
+
+    return true;
+  }
+  
+  public void clear() {
+    while (size() > 0) {
+      poll();
+    }
+  }
+  
+  public T element() {
+    emptyCheck();
+    return peek();
+  }
+  
+  public T remove() {
+    emptyCheck();
+    return poll();
+  }
+  
+  private void emptyCheck() {
+    if (size() == 0) {
+      throw new NoSuchElementException();
+    }
+  }
+}

classpath/java/util/Queue.java

@@ -0,0 +1,20 @@
+/* Copyright (c) 2012, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.util;
+
+public interface Queue<T> extends Collection<T>, Iterable<T> {
+  public boolean add(T element);
+  public T element();
+  public boolean offer(T element);
+  public T peek();
+  public T poll();
+  public T remove();
+}