--- jsr166/src/main/java/util/AbstractQueue.java 2003/09/12 17:13:11 1.15 +++ jsr166/src/main/java/util/AbstractQueue.java 2005/07/18 19:14:17 1.31 @@ -1,10 +1,11 @@ /* * 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; +import java.util.*; // for javadoc (till 6280605 is fixed) /** * This class provides skeletal implementations of some {@link Queue} @@ -19,13 +20,19 @@ package java.util; *
A Queue implementation that extends this class must * minimally define a method {@link Queue#offer} which does not permit * insertion of null 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}. + * + *
This class is a member of the
+ *
+ * Java Collections Framework.
*
* @since 1.5
* @author Doug Lea
+ * @param This implementation returns true if offer succeeds,
+ * else throws an IllegalStateException.
+ *
+ * @param e the element to add
+ * @return true (as specified by {@link Collection#add})
+ * @throws IllegalStateException if the element cannot be added at this
+ * time due to capacity restrictions
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this queue
+ * @throws NullPointerException if the specified element is null and
+ * this queue not permit null elements
+ * @throws IllegalArgumentException if some property of this element
+ * prevents it from being added to this queue
*/
- public boolean add(E o) {
- if (offer(o))
+ public boolean add(E e) {
+ if (offer(e))
return true;
else
throw new IllegalStateException("Queue full");
}
/**
- * Retrieves and removes the head of this queue.
- * This implementation returns the result of poll
+ * Retrieves and removes the head of this queue. This method differs
+ * from {@link #poll poll} only in that it throws an exception if this
+ * queue is empty.
+ *
+ * This implementation returns the result of poll
* unless the queue is empty.
*
- * @return the head of this queue.
- * @throws NoSuchElementException if this queue is empty.
+ * @return the head of this queue
+ * @throws NoSuchElementException if this queue is empty
*/
public E remove() {
E x = poll();
@@ -85,14 +90,16 @@ public abstract class AbstractQueue This implementation returns the result of peek
* unless the queue is empty.
*
- * @return the head of this queue.
- * @throws NoSuchElementException if this queue is empty.
+ * @return the head of this queue
+ * @throws NoSuchElementException if this queue is empty
*/
public E element() {
E x = peek();
@@ -103,8 +110,9 @@ public abstract class AbstractQueue This implementation repeatedly invokes {@link #poll poll} until it
* returns null.
*/
@@ -113,83 +121,47 @@ public abstract class AbstractQueue
- *
- * 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 remove method.
- *
- * @param c elements to be removed from this collection.
- * @return true 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.
- *
- * 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 remove method.
- *
- * @param c elements to be retained in this collection.
- * @return true 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.)
- *
- * This implementation iterates over the specified collection,
- * and uses the add method to insert each object returned by
- * the iterator to this queue, in turn.
- *
- * @param c collection whose elements are to be added to this queue
- * @return true if this queue changed as a result of the
- * call.
- * @throws NullPointerException if c or any element in c
- * is null
- * @throws IllegalStateException if any element cannot be added.
- *
+ * queue. Attempts to addAll of a queue to itself result in
+ * IllegalArgumentException. Further, the behavior of
+ * this operation is undefined if the specified collection is
+ * modified while the operation is in progress.
+ *
+ * This implementation iterates over the specified collection,
+ * and adds each element returned by the iterator to this
+ * queue, in turn. A runtime exception encountered while
+ * trying to add an element (including, in particular, a
+ * null element) may result in only some of the elements
+ * having been successfully added when the associated exception is
+ * thrown.
+ *
+ * @param c collection containing elements to be added to this queue
+ * @return true if this queue changed as a result of the call
+ * @throws ClassCastException if the class of an element of the specified
+ * collection prevents it from being added to this queue
+ * @throws NullPointerException if the specified collection contains a
+ * null element and this queue does not permit null elements,
+ * or if the specified collection is null
+ * @throws IllegalArgumentException if some property of an element of the
+ * specified collection prevents it from being added to this
+ * queue, or if the specified collection is this queue
+ * @throws IllegalStateException if not all the elements can be added at
+ * this time due to insertion restrictions
+ * @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;
}
}