--- jsr166/src/main/java/util/AbstractQueue.java	2003/07/26 13:17:51	1.5
+++ jsr166/src/main/java/util/AbstractQueue.java	2004/01/27 11:36:26	1.25
@@ -1,30 +1,76 @@
 /*
  * Written by Doug Lea with assistance from members of JCP JSR-166
- * Expert Group and released to the public domain. Use, modify, and
- * redistribute this code in any way without acknowledgement.
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/licenses/publicdomain
  */
 
 package java.util;
 
 /**
- * AbstractQueue provides default implementations of add, remove, and
- * element based on offer, poll, and peek, respectively but that throw
- * exceptions instead of indicating failure via false or null returns.
- * The provided implementations all assume that the base implementation
- * does <em>not</em> allow <tt>null</tt> elements.
+ * This class provides skeletal implementations of some {@link Queue}
+ * operations. The implementations in this class are appropriate when
+ * the base implementation does <em>not</em> allow <tt>null</tt>
+ * elements.  Methods {@link #add add}, {@link #remove remove}, and
+ * {@link #element element} are based on {@link #offer offer}, {@link
+ * #poll poll}, and {@link #peek peek}, respectively but throw
+ * exceptions instead of indicating failure via <tt>false</tt> or
+ * <tt>null</tt> returns.
+ *
+ * <p> A <tt>Queue</tt> implementation that extends this class must
+ * minimally define a method {@link Queue#offer} which does not permit
+ * insertion of <tt>null</tt> elements, along with methods {@link
+ * Queue#peek}, {@link Queue#poll}, {@link Collection#size}, and a
+ * {@link Collection#iterator} supporting {@link
+ * Iterator#remove}. Typically, additional methods will be overridden
+ * as well. If these requirements cannot be met, consider instead
+ * subclassing {@link AbstractCollection}.
+ *
+ * <p>This class is a member of the
+ * <a href="{@docRoot}/../guide/collections/index.html">
+ * Java Collections Framework</a>.
+ *  
  * @since 1.5
  * @author Doug Lea
+ * @param <E> the type of elements held in this collection
  */
+public abstract class AbstractQueue<E>
+    extends AbstractCollection<E>
+    implements Queue<E> {
+
+    /**
+     * Constructor for use by subclasses.
+     */
+    protected AbstractQueue() {
+    }
 
-public abstract class AbstractQueue<E> extends AbstractCollection<E> implements Queue<E> {
 
-    public boolean add(E x) {
-        if (offer(x))
+    /**
+     * Adds the specified element to this queue. This implementation
+     * returns <tt>true</tt> if <tt>offer</tt> succeeds, else
+     * throws an IllegalStateException. 
+     * 
+     * @param o the element
+     * @return <tt>true</tt> (as per the general contract of
+     *         <tt>Collection.add</tt>).
+     *
+     * @throws NullPointerException if the specified element is <tt>null</tt>
+     * @throws IllegalStateException if element cannot be added
+     */
+    public boolean add(E o) {
+        if (offer(o))
             return true;
         else
             throw new IllegalStateException("Queue full");
     }
 
+    /**
+     * Retrieves and removes the head of this queue.
+     * This implementation returns the result of <tt>poll</tt>
+     * unless the queue is empty.
+     *
+     * @return the head of this queue.
+     * @throws NoSuchElementException if this queue is empty.
+     */
     public E remove() {
         E x = poll();
         if (x != null)
@@ -33,6 +79,15 @@ public abstract class AbstractQueue<E> e
             throw new NoSuchElementException();
     }
 
+
+    /**
+     * Retrieves, but does not remove, the head of this queue.  
+     * This implementation returns the result of <tt>peek</tt>
+     * unless the queue is empty.
+     *
+     * @return the head of this queue.
+     * @throws NoSuchElementException if this queue is empty.
+     */
     public E element() {
         E x = peek();
         if (x != null)
@@ -41,10 +96,53 @@ public abstract class AbstractQueue<E> e
             throw new NoSuchElementException();
     }
 
+    /**
+     * Removes all of the elements from this collection.
+     * The collection will be empty after this call returns.
+     * <p>This implementation repeatedly invokes {@link #poll poll} until it
+     * returns <tt>null</tt>.
+     */
     public void clear() {
         while (poll() != null)
             ;
     }
 
-    public abstract Iterator<E> iterator();
+    /**
+     * Adds all of the elements in the specified collection to this
+     * queue.  Attempts to addAll of a queue to itself result in
+     * <tt>IllegalArgumentException</tt>. Further, the behavior of
+     * this operation is undefined if the specified collection is
+     * modified while the operation is in progress.
+     *
+     * <p>This implementation iterates over the specified collection,
+     * and adds each element returned by the iterator to this
+     * collection, in turn.  A runtime exception encountered while
+     * trying to add an element (including, in particular, a
+     * <tt>null</tt> element) may result in only some of the elements
+     * having been successfully added when the associated exception is
+     * thrown.
+     *
+     * @param c collection whose elements are to be added to this collection.
+     * @return <tt>true</tt> if this collection changed as a result of the
+     *         call.
+     * @throws NullPointerException if the specified collection or
+     * any of its elements are null.
+     * @throws IllegalArgumentException if c is this queue.
+     * 
+     * @see #add(Object)
+     */
+    public boolean addAll(Collection<? extends E> c) {
+        if (c == null)
+            throw new NullPointerException();
+        if (c == this)
+            throw new IllegalArgumentException();
+        boolean modified = false;
+        Iterator<? extends E> e = c.iterator();
+        while (e.hasNext()) {
+            if (add(e.next()))
+                modified = true;
+        }
+        return modified;
+    }
+
 }