1 |
+ |
/* |
2 |
+ |
* Written by Doug Lea with assistance from members of JCP JSR-166 |
3 |
+ |
* Expert Group and released to the public domain. Use, modify, and |
4 |
+ |
* redistribute this code in any way without acknowledgement. |
5 |
+ |
*/ |
6 |
+ |
|
7 |
|
package java.util; |
8 |
|
|
9 |
|
/** |
23 |
|
* failure. It is designed for use in collections in which failure to |
24 |
|
* add is a normal, rather than exceptional occurrence, for example, |
25 |
|
* in fixed-capacity (or “bounded”) queues. |
26 |
< |
* |
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. For example, |
30 |
< |
* in FIFO queues, they remove and return the oldest element in the queue. |
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), 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>. |
75 |
|
|
76 |
|
/** |
77 |
|
* Remove and return an element from the queue if one is available. |
68 |
– |
* Exactly which element is removed from the queue is a function |
69 |
– |
* of the queue's ordering policy, which differs from implementation |
70 |
– |
* to implementation. Possible orderings include (but are not limited |
71 |
– |
* to) first-in-first-out (FIFO), element priority, and arbitrary. |
78 |
|
* |
79 |
|
* @return an element previously on the queue, or <tt>null</tt> if the |
80 |
< |
* queue is empty. |
80 |
> |
* queue is empty. |
81 |
|
*/ |
82 |
|
public E poll(); |
83 |
|
|
84 |
|
/** |
85 |
|
* Remove and return an element from the queue. This method differs |
86 |
|
* from the <tt>poll</tt> method in that it throws an exception if the |
87 |
< |
* queue is empty. |
87 |
> |
* queue is empty. |
88 |
|
* |
89 |
|
* @return an element previously on the queue. |
90 |
|
* @throws NoSuchElementException if the queue is empty. |