| 8 |
|
|
| 9 |
|
/** |
| 10 |
|
* A collection designed for holding elements prior to processing. |
| 11 |
< |
* Besides basic {@link Collection} operations, queues provide |
| 11 |
> |
* Besides basic {@link java.util.Collection Collection} operations, queues provide |
| 12 |
|
* additional insertion, extraction, and inspection operations. |
| 13 |
|
* |
| 14 |
|
* <p>Queues typically, but do not necessarily, order elements in a |
| 18 |
|
* stacks) which order the elements LIFO (last-in-first-out). |
| 19 |
|
* Whatever the ordering used, the <em>head</em> of the queue is that element |
| 20 |
|
* which would be removed by a call to {@link #remove() } or {@link #poll()}. |
| 21 |
< |
* Every Queue implementation must specify its ordering guarantees. |
| 21 |
> |
* Every <tt>Queue</tt> implementation must specify its ordering guarantees. |
| 22 |
|
* |
| 23 |
< |
* <p>The {@link #offer(E)} method adds an element if possible, otherwise |
| 24 |
< |
* returning <tt>false</tt>. This differs from the {@link |
| 25 |
< |
* Collections#add(Object)} method, which throws an unchecked exception upon |
| 23 |
> |
* <p>The {@link #offer offer} method adds an element if possible, otherwise |
| 24 |
> |
* returning <tt>false</tt>. This differs from the |
| 25 |
> |
* {@link java.util.Collection#add Collection.add} |
| 26 |
> |
* method, which throws an unchecked exception upon |
| 27 |
|
* failure. It is designed for use in collections in which failure to |
| 28 |
|
* add is a normal, rather than exceptional occurrence, for example, |
| 29 |
|
* in fixed-capacity (or "bounded") queues. |
| 38 |
|
* while the <tt>poll()</tt> method returns <tt>null</tt>. |
| 39 |
|
* |
| 40 |
|
* <p>The {@link #element()} and {@link #peek()} methods return, but do |
| 41 |
< |
* not delete, the head of the queue. |
| 41 |
> |
* not remove, the head of the queue. |
| 42 |
|
* |
| 43 |
|
* <p>The <tt>Queue</tt> interface does not define the <i>blocking queue |
| 44 |
|
* methods</i>, which are common in concurrent programming. These methods, |
| 58 |
|
* <a href="{@docRoot}/../guide/collections/index.html"> |
| 59 |
|
* Java Collections Framework</a>. |
| 60 |
|
* |
| 61 |
< |
* @see Collection |
| 61 |
> |
* @see java.util.Collection |
| 62 |
|
* @see LinkedList |
| 63 |
|
* @see PriorityQueue |
| 64 |
|
* @see java.util.concurrent.LinkedQueue |
| 74 |
|
/** |
| 75 |
|
* Add the specified element to this queue, if possible. |
| 76 |
|
* |
| 77 |
< |
* @param element the element to add. |
| 77 |
> |
* @param o the element to add. |
| 78 |
|
* @return <tt>true</tt> if it was possible to add the element to |
| 79 |
< |
* this queue. |
| 79 |
> |
* this queue, else <tt>false</tt> |
| 80 |
|
*/ |
| 81 |
< |
boolean offer(E element); |
| 81 |
> |
boolean offer(E o); |
| 82 |
|
|
| 83 |
|
/** |
| 84 |
|
* Retrieve and remove the head of this queue, if it is available. |
| 91 |
|
/** |
| 92 |
|
* Retrieve and remove the head of this queue. |
| 93 |
|
* This method differs |
| 94 |
< |
* from the <tt>poll</tt> method in that it throws an exception if the |
| 94 |
> |
* from the <tt>poll</tt> method in that it throws an exception if this |
| 95 |
|
* queue is empty. |
| 96 |
|
* |
| 97 |
|
* @return the head of this queue. |
| 100 |
|
E remove(); |
| 101 |
|
|
| 102 |
|
/** |
| 103 |
< |
* Retrieve, but do not remove, the head of this queue, or <tt>null</tt> |
| 104 |
< |
* if this queue is empty. This method differs from the <tt>poll</tt> |
| 105 |
< |
* method only in that this method does not remove the element from |
| 103 |
> |
* Retrieve, but do not remove, the head of this queue. |
| 104 |
> |
* This method differs from the <tt>poll</tt> |
| 105 |
> |
* method only in that this method does not remove the head element from |
| 106 |
|
* this queue. |
| 107 |
|
* |
| 108 |
|
* @return the head of this queue, or <tt>null</tt> if this queue is empty. |
