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root/jsr166/jsr166/src/main/java/util/Queue.java

Comparing jsr166/src/main/java/util/Queue.java (file contents):
Revision 1.6 by brian, Mon Jun 23 02:26:15 2003 UTC vs.
Revision 1.7 by dl, Tue Jun 24 14:34:30 2003 UTC

#	Line 25 | Line 25 | package java.util;
25		* in fixed-capacity (or “bounded”) queues.
26
27		*
28	<	* <p>The {@link #remove()} and {@link #poll()} methods remove and return an
29	<	* element in accord with the implementation's ordering policy.
30	<	* Exactly which element is removed from the queue is a function
31	<	* of the queue's ordering policy, which differs from implementation
32	<	* to implementation.  Possible orderings include (but are not limited
33	<	* to) first-in-first-out (FIFO), last-in-first-out (LIFO), element priority, and arbitrary.
34	<	* The <tt>remove()</tt> and <tt>poll()</tt> methods differ only in their
35	<	* behavior when the queue is empty: the <tt>remove()</tt> method throws an
36	<	* exception, while the <tt>poll()</tt> method returns <tt>null</tt>.
28	>	* <p>The {@link #remove()} and {@link #poll()} methods remove and
29	>	* return an element in accord with the implementation's ordering
30	>	* policy.  Exactly which element is removed from the queue is a
31	>	* function of the queue's ordering policy, which differs from
32	>	* implementation to implementation.  Possible orderings include (but
33	>	* are not limited to) first-in-first-out (FIFO), last-in-first-out
34	>	* (LIFO), element priority, and arbitrary.  The <tt>remove()</tt> and
35	>	* <tt>poll()</tt> methods differ only in their behavior when the
36	>	* queue is empty: the <tt>remove()</tt> method throws an exception,
37	>	* while the <tt>poll()</tt> method returns <tt>null</tt>.
38		*
39		* <p>The {@link #element()} and {@link #peek()} methods return but do
40		* not delete the element that would be obtained by a call to
#	Line 45 | Line 46 | package java.util;
46		* defined in the {@link java.util.concurrent.BlockingQueue} interface, which
47		* extends this interface.
48		*
49	<	* <p><tt>Queue</tt> implementations generally do not allow insertion of
50	<	* <tt>null</tt> elements, although some implementations, such as
49	>	* <p><tt>Queue</tt> implementations generally do not allow insertion
50	>	* of <tt>null</tt> elements, although some implementations, such as
51		* {@link LinkedList}, do not prohibit insertion of <tt>null</tt>.
52	<	* Even in the implementations that permit it, <tt>null</tt> should not be inserted into
53	<	* a <tt>Queue</tt>, as <tt>null</tt> is also used as a special return value
54	<	* by the <tt>poll</tt> method to indicate that the queue contains no
55	<	* elements.
52	>	* Even in the implementations that permit it, <tt>null</tt> should
53	>	* not be inserted into a <tt>Queue</tt>, as <tt>null</tt> is also
54	>	* used as a special return value by the <tt>poll</tt> method to
55	>	* indicate that the queue contains no elements.
56		*
57		* <p>This interface is a member of the
58		* <a href="{@docRoot}/../guide/collections/index.html">
#	Line 65 | Line 66 | package java.util;
66		* @see java.util.concurrent.ArrayBlockingQueue
67		* @see java.util.concurrent.LinkedBlockingQueue
68		* @see java.util.concurrent.PriorityBlockingQueue
69	+	* @since 1.5
70	+	* @author Doug Lea
71		*/
72		public interface Queue<E> extends Collection<E> {
73		/**
#	Line 73 | Line 76 | public interface Queue<E> extends Collec
76		* @param element the element to add.
77		* @return true if it was possible to add the element to the queue.
78		*/
79	<	public boolean offer(E element);
79	>	boolean offer(E element);
80
81		/**
82		* Remove and return an element from the queue if one is available.
#	Line 81 | Line 84 | public interface Queue<E> extends Collec
84		* @return an element previously on the queue, or <tt>null</tt> if the
85		*         queue is empty.
86		*/
87	<	public E poll();
87	>	E poll();
88
89		/**
90		* Remove and return an element from the queue.  This method differs
#	Line 91 | Line 94 | public interface Queue<E> extends Collec
94		* @return an element previously on the queue.
95		* @throws NoSuchElementException if the queue is empty.
96		*/
97	<	public E remove() throws NoSuchElementException;
97	>	E remove() throws NoSuchElementException;
98
99		/**
100		* Return, but do not remove, an element from the queue, or <tt>null</tt>
#	Line 101 | Line 104 | public interface Queue<E> extends Collec
104		*
105		* @return an element on the queue, or <tt>null</tt> if the queue is empty.
106		*/
107	<	public E peek();
107	>	E peek();
108
109		/**
110		* Return, but do not remove, an element from the queue.  This method
#	Line 111 | Line 114 | public interface Queue<E> extends Collec
114		* @return an element on the queue.
115		* @throws NoSuchElementException if the queue is empty.
116		*/
117	<	public E element() throws NoSuchElementException;
117	>	E element() throws NoSuchElementException;
118		}

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