--- jsr166/src/main/java/util/Queue.java 2003/08/04 01:54:13 1.13 +++ jsr166/src/main/java/util/Queue.java 2003/09/12 15:38:26 1.17 @@ -16,17 +16,20 @@ package java.util; * priority queues, which order elements according to a supplied * comparator, or the elements' natural ordering, and LIFO queues (or * stacks) which order the elements LIFO (last-in-first-out). - * Whatever the ordering used, the head of the queue is that element - * which would be removed by a call to {@link #remove() } or {@link #poll()}. - * Every Queue implementation must specify its ordering guarantees. - * - *
The {@link #offer offer} method adds an element if possible, otherwise - * returning false. This differs from the - * {@link java.util.Collection#add Collection.add} - * method, which throws an unchecked exception upon - * failure. It is designed for use in collections in which failure to - * add is a normal, rather than exceptional occurrence, for example, - * in fixed-capacity (or "bounded") queues. + * Whatever the ordering used, the head of the queue is that + * element which would be removed by a call to {@link #remove() } or + * {@link #poll()}. In a FIFO queue, all new elements are inserted at + * the tail of the queue. Other kinds of queues may use + * different placement rules. Every Queue implementation + * must specify its ordering properties. + * + *
The {@link #offer offer} method inserts an element if possible, + * otherwise returning false. This differs from the {@link + * java.util.Collection#add Collection.add} method, which can fail to + * add an element only by throwing an unchecked exception. The + * offer method is designed for use when failure is a normal, + * rather than exceptional occurrence, for example, in fixed-capacity + * (or "bounded") queues. * *
The {@link #remove()} and {@link #poll()} methods remove and * return the head of the queue. @@ -54,6 +57,14 @@ package java.util; * used as a special return value by the poll method to * indicate that the queue contains no elements. * + *
Queue implementations generally do not define + * element-based versions of methods equals and + * hashCode but instead inherit the identity based versions + * from class Object, because element-based equality is not + * always well-defined for queues with the same elements but different + * ordering properties. + * + * *
This interface is a member of the
*
* Java Collections Framework.
@@ -61,7 +72,7 @@ package java.util;
* @see java.util.Collection
* @see LinkedList
* @see PriorityQueue
- * @see java.util.concurrent.LinkedQueue
+ * @see java.util.concurrent.LinkedBlockingQueue
* @see java.util.concurrent.BlockingQueue
* @see java.util.concurrent.ArrayBlockingQueue
* @see java.util.concurrent.LinkedBlockingQueue
@@ -72,16 +83,20 @@ package java.util;
public interface Queue