| 8 |
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|
| 9 |
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/** |
| 10 |
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* A collection designed for holding elements prior to processing. |
| 11 |
< |
* Besides basic {@link java.util.Collection Collection} operations, |
| 12 |
< |
* queues provide additional insertion, extraction, and inspection |
| 13 |
< |
* operations. Each of these methods exists in two forms: one throws |
| 14 |
< |
* an exception if the operation fails, the other returns a special |
| 15 |
< |
* value (either {@code null} or {@code false}, depending on the |
| 16 |
< |
* operation). The latter form of the insert operation is designed |
| 17 |
< |
* specifically for use with capacity-restricted {@code Queue} |
| 18 |
< |
* implementations; in most implementations, insert operations cannot |
| 19 |
< |
* fail. |
| 11 |
> |
* Besides basic {@link Collection} operations, queues provide |
| 12 |
> |
* additional insertion, extraction, and inspection operations. |
| 13 |
> |
* Each of these methods exists in two forms: one throws an exception |
| 14 |
> |
* if the operation fails, the other returns a special value (either |
| 15 |
> |
* {@code null} or {@code false}, depending on the operation). The |
| 16 |
> |
* latter form of the insert operation is designed specifically for |
| 17 |
> |
* use with capacity-restricted {@code Queue} implementations; in most |
| 18 |
> |
* implementations, insert operations cannot fail. |
| 19 |
|
* |
| 20 |
|
* <table BORDER CELLPADDING=3 CELLSPACING=1> |
| 21 |
|
* <caption>Summary of Queue methods</caption> |
| 26 |
|
* </tr> |
| 27 |
|
* <tr> |
| 28 |
|
* <td><b>Insert</b></td> |
| 29 |
< |
* <td>{@link Queue#add add(e)}</td> |
| 30 |
< |
* <td>{@link Queue#offer offer(e)}</td> |
| 29 |
> |
* <td>{@link #add(Object) add(e)}</td> |
| 30 |
> |
* <td>{@link #offer(Object) offer(e)}</td> |
| 31 |
|
* </tr> |
| 32 |
|
* <tr> |
| 33 |
|
* <td><b>Remove</b></td> |
| 34 |
< |
* <td>{@link Queue#remove remove()}</td> |
| 35 |
< |
* <td>{@link Queue#poll poll()}</td> |
| 34 |
> |
* <td>{@link #remove() remove()}</td> |
| 35 |
> |
* <td>{@link #poll() poll()}</td> |
| 36 |
|
* </tr> |
| 37 |
|
* <tr> |
| 38 |
|
* <td><b>Examine</b></td> |
| 39 |
< |
* <td>{@link Queue#element element()}</td> |
| 40 |
< |
* <td>{@link Queue#peek peek()}</td> |
| 39 |
> |
* <td>{@link #element() element()}</td> |
| 40 |
> |
* <td>{@link #peek() peek()}</td> |
| 41 |
|
* </tr> |
| 42 |
|
* </table> |
| 43 |
|
* |
| 47 |
|
* comparator, or the elements' natural ordering, and LIFO queues (or |
| 48 |
|
* stacks) which order the elements LIFO (last-in-first-out). |
| 49 |
|
* Whatever the ordering used, the <em>head</em> of the queue is that |
| 50 |
< |
* element which would be removed by a call to {@link #remove() } or |
| 50 |
> |
* element which would be removed by a call to {@link #remove()} or |
| 51 |
|
* {@link #poll()}. In a FIFO queue, all new elements are inserted at |
| 52 |
|
* the <em>tail</em> of the queue. Other kinds of queues may use |
| 53 |
|
* different placement rules. Every {@code Queue} implementation |
| 143 |
|
|
| 144 |
|
/** |
| 145 |
|
* Retrieves and removes the head of this queue. This method differs |
| 146 |
< |
* from {@link #poll poll} only in that it throws an exception if this |
| 147 |
< |
* queue is empty. |
| 146 |
> |
* from {@link #poll() poll()} only in that it throws an exception if |
| 147 |
> |
* this queue is empty. |
| 148 |
|
* |
| 149 |
|
* @return the head of this queue |
| 150 |
|
* @throws NoSuchElementException if this queue is empty |
