--- jsr166/src/main/java/util/AbstractQueue.java 2003/07/28 04:11:54 1.6 +++ jsr166/src/main/java/util/AbstractQueue.java 2004/01/27 11:36:26 1.25 @@ -1,31 +1,77 @@ /* * 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 not allow null elements. + * This class provides skeletal implementations of some {@link Queue} + * operations. The implementations in this class are appropriate when + * the base implementation does not allow null + * 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 false or + * null returns. + * + *
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}, 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 repeatedly invokes {@link #poll poll} until it
+ * returns null.
+ */
public void clear() {
while (poll() != null)
;
}
- // why is this here? Won't Collection declare this itself??? - David
- public abstract Iterator 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
+ * null 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 true 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;
+ }
+}