--- jsr166/src/main/java/util/AbstractQueue.java	2003/09/12 15:38:26	1.14
+++ jsr166/src/main/java/util/AbstractQueue.java	2003/10/19 13:38:29	1.21
@@ -19,13 +19,15 @@ package java.util;
  * <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}, {@link
- * Collection#remove}, and a {@link Collection#iterator} supporting
- * {@link Iterator#remove}. If these requirements cannot be met,
- * consider instead subclassing {@link AbstractCollection}.
+ * 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}.
  *
  * @since 1.5
  * @author Doug Lea
+ * @param <E> the type of elements held in this collection
  */
 public abstract class AbstractQueue<E>
     extends AbstractCollection<E>
@@ -37,24 +39,12 @@ public abstract class AbstractQueue<E>
     protected AbstractQueue() {
     }
 
-    /**
-     * Inserts the specified element to this queue, if possible.
-     *
-     * @param o the element to add.
-     * @return <tt>true</tt> if it was possible to add the element to
-     *         this queue, else <tt>false</tt>
-     * @throws NullPointerException if the specified element is <tt>null</tt>
-     */
-    //    public boolean offer(E o) { return false; }
-    // FIXME: Replace above no-op with following abstract version
-    // when javac allows it.
-    public abstract boolean offer(E o);
 
     /**
      * Adds the specified element to this queue. This implementation
      * returns <tt>true</tt> if <tt>offer</tt> succeeds, else
      * throws an IllegalStateException. 
-     * th
+     * 
      * @param o the element
      * @return <tt>true</tt> (as per the general contract of
      *         <tt>Collection.add</tt>).
@@ -113,83 +103,42 @@ public abstract class AbstractQueue<E>
             ;
     }
 
-    // Declarations that mostly just remove optionality clauses.
-
-    /**
-     * Removes a single instance of the specified element from this
-     * queue, if one is present.  More formally, removes an element
-     * <tt>e</tt> such that <tt>(o==null ? e==null :
-     * o.equals(e))</tt>, if the queue contains such an element.
-     * Returns <tt>true</tt> if the queue contained the specified
-     * element (or equivalently, if the queue changed as a result of
-     * the call).
-     *
-     * @param o the element to remove
-     * @return true if the element was removed
-     */
-    public abstract boolean remove(Object o);
-
-    /**
-     * Removes from this queue all of its elements that are contained in
-     * the specified collection. <p>
-     *
-     * This implementation iterates over this queue, checking each
-     * element returned by the iterator in turn to see if it's contained
-     * in the specified collection.  If it's so contained, it's removed from
-     * this queue with the iterator's <tt>remove</tt> method.<p>
-     *
-     * @param c elements to be removed from this collection.
-     * @return <tt>true</tt> if this queue changed as a result of the
-     *         call.
-     * @throws NullPointerException if the specified collection is null.
-     */
-    public boolean removeAll(Collection<?> c) {
-        return super.removeAll(c);
-    }
-
-    /**
-     * Retains only the elements in this queue that are contained in the
-     * specified collection.  In other words, removes
-     * from this queue all of its elements that are not contained in the
-     * specified collection. <p>
-     *
-     * This implementation iterates over this queue, checking each
-     * element returned by the iterator in turn to see if it's contained
-     * in the specified collection.  If it's not so contained, it's removed
-     * from this queue with the iterator's <tt>remove</tt> method.<p>
-     *
-     * @param c elements to be retained in this collection.
-     * @return <tt>true</tt> if this queue changed as a result of the
-     *         call.
-     * @throws NullPointerException if the specified collection is null.
-     *
-     */
-    public boolean retainAll(Collection<?> c) {
-        return super.retainAll(c);
-    }
-
     /**
      * Adds all of the elements in the specified collection to this
-     * queue.  The behavior of this operation is undefined if the
-     * specified collection is modified while the operation is in
-     * progress.  (This implies that the behavior of this call is
-     * undefined if the specified collection is this queue, and this
-     * queue is nonempty.)
-     *
-     * <p> This implementation iterates over the specified collection,
-     * and uses the <tt>add</tt> method to insert each object returned by
-     * the iterator to this queue, in turn.
+     * 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 queue
-     * @return <tt>true</tt> if this queue changed as a result of the
+     * @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 <tt>c</tt> or any element in <tt>c</tt>
-     * is <tt>null</tt>
-     * @throws IllegalStateException if any element cannot be added.
+     * @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) {
-        return super.addAll(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;
     }
 
 }