util/concurrent/CompletionService.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain. Use, modify, and
 * redistribute this code in any way without acknowledgement.
 */

package java.util.concurrent;

/**
 * A service that decouples the production of new asynchronous tasks
 * and the comsumption of the reasults of completed tasks.
 */
public interface CompletionService<V> {
    /**
     * Submits a value-returning task for execution and returns a Future
     * representing the pending results of the task. Upon completion,
     * this task may be taken or polled.
     *
     * @param task the task to submit
     * @return a Future representing pending completion of the task
     * @throws RejectedExecutionException if task cannot be scheduled
     * for execution
     */
    Future<V> submit(Callable<V> task);


    /**
     * Submits a Runnable task for execution and returns a Future 
     * representing that task.Upon completion,
     * this task may be taken or polled.
     *
     * @param task the task to submit
     * @param result the result to return upon successful completion
     * @return a Future representing pending completion of the task,
     * and whose <tt>get()</tt> method will return the given result value 
     * upon completion
     * @throws RejectedExecutionException if task cannot be scheduled
     * for execution
     */
    Future<V> submit(Runnable task, V result);

    /**
     * Retrieves and removes the Future representing the next
     * completed task, waiting if none are yet present.
     * @return the Future representing the next completed task
     * @throws InterruptedException if interrupted while waiting.
     */
    Future<V> take() throws InterruptedException;


    /**
     * Retrieves and removes the Future representing the next
     * completed task or <tt>null</tt> if none are present.
     *
     * @return the Future representing the next completed task, or
     * <tt>null</tt> if none are present.
     */
    Future<V> poll();

    /**
     * Retrieves and removes the Future representing the next
     * completed task, waiting if necessary up to the specified wait
     * time if none are yet present.
     * @param timeout how long to wait before giving up, in units of
     * <tt>unit</tt>
     * @param unit a <tt>TimeUnit</tt> determining how to interpret the
     * <tt>timeout</tt> parameter
     * @return the Future representing the next completed task or
     * <tt>null</tt> if the specified waiting time elapses before one
     * is present.
     * @throws InterruptedException if interrupted while waiting.
     */
    Future<V> poll(long timeout, TimeUnit unit) throws InterruptedException;
}
Revision:	1.1
Committed:	Mon Dec 15 00:29:49 2003 UTC (20 years, 5 months ago) by dl
Branch:	MAIN
Log Message:	Added CompletionService; Executor any/all methods now require lists
#	Content
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.concurrent;
8
9	/**
10	* A service that decouples the production of new asynchronous tasks
11	* and the comsumption of the reasults of completed tasks.
12	*/
13	public interface CompletionService<V> {
14	/**
15	* Submits a value-returning task for execution and returns a Future
16	* representing the pending results of the task. Upon completion,
17	* this task may be taken or polled.
18	*
19	* @param task the task to submit
20	* @return a Future representing pending completion of the task
21	* @throws RejectedExecutionException if task cannot be scheduled
22	* for execution
23	*/
24	Future<V> submit(Callable<V> task);
25
26
27	/**
28	* Submits a Runnable task for execution and returns a Future
29	* representing that task.Upon completion,
30	* this task may be taken or polled.
31	*
32	* @param task the task to submit
33	* @param result the result to return upon successful completion
34	* @return a Future representing pending completion of the task,
35	* and whose <tt>get()</tt> method will return the given result value
36	* upon completion
37	* @throws RejectedExecutionException if task cannot be scheduled
38	* for execution
39	*/
40	Future<V> submit(Runnable task, V result);
41
42	/**
43	* Retrieves and removes the Future representing the next
44	* completed task, waiting if none are yet present.
45	* @return the Future representing the next completed task
46	* @throws InterruptedException if interrupted while waiting.
47	*/
48	Future<V> take() throws InterruptedException;
49
50
51	/**
52	* Retrieves and removes the Future representing the next
53	* completed task or <tt>null</tt> if none are present.
54	*
55	* @return the Future representing the next completed task, or
56	* <tt>null</tt> if none are present.
57	*/
58	Future<V> poll();
59
60	/**
61	* Retrieves and removes the Future representing the next
62	* completed task, waiting if necessary up to the specified wait
63	* time if none are yet present.
64	* @param timeout how long to wait before giving up, in units of
65	* <tt>unit</tt>
66	* @param unit a <tt>TimeUnit</tt> determining how to interpret the
67	* <tt>timeout</tt> parameter
68	* @return the Future representing the next completed task or
69	* <tt>null</tt> if the specified waiting time elapses before one
70	* is present.
71	* @throws InterruptedException if interrupted while waiting.
72	*/
73	Future<V> poll(long timeout, TimeUnit unit) throws InterruptedException;
74	}