util/concurrent/ExecutorService.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;

import java.util.List;

/**
 * An executor that provides methods to manage termination.  An
 * <tt>ExecutorService</tt> can be shut down, which will cause it to
 * stop accepting new tasks.  After being shut down, the executor will
 * eventually terminate, at which point no tasks are actively
 * executing, no tasks are awaiting execution, and no new tasks can be
 * submitted.
 *
 * <p>The <tt>Executors</tt> class provides factory methods for the
 * executor services provided in <tt>java.util.concurrent</tt>.
 *
 * @since 1.5
 * @see Executors
 *
 * @spec JSR-166
 * @revised $Date: 2003/06/24 14:34:48 $
 * @editor $Author: dl $
 * @author Doug Lea
 */
public interface ExecutorService extends Executor {

    /**
     * Initiates an orderly shutdown in which previously submitted
     * tasks are executed, but no new tasks will be
     * accepted. Invocation has no additional effect if already shut
     * down.
     *
     */
    void shutdown();

    /**
     * Attempts to stop all actively executing tasks, halts the
     * processing of waiting tasks, and returns a list of the tasks that were
     * awaiting execution. 
     *  
     * <p>There are no guarantees beyond best-effort attempts to stop
     * processing actively executing tasks.  For example, typical
     * implementations will cancel via {@link Thread#interrupt}, so if any
     * tasks mask or fail to respond to interrupts, they may never terminate.
     *
     * @return list of tasks that never commenced execution
     */
    List shutdownNow();

    /**
     * Returns <tt>true</tt> if this executor has been shut down.
     *
     * @return <tt>true</tt> if this executor has been shut down
     */
    boolean isShutdown();

    /**
     * Returns <tt>true</tt> if all tasks have completed following shut down.
     * Note that <tt>isTerminated</tt> is never <tt>true</tt> unless
     * either <tt>shutdown</tt> or <tt>shutdownNow</tt> was called first.
     *
     * @return <tt>true</tt> if all tasks have completed following shut down
     */
    boolean isTerminated();

    /**
     * Blocks until all tasks have completed execution after a shutdown
     * request, or the timeout occurs, or the current thread is
     * interrupted, whichever happens first.
     *
     * @param timeout the maximum time to wait
     * @param unit the time unit of the timeout argument
     * @return <tt>true</tt> if this executor terminated and <tt>false</tt>
     * if the timeout elapsed before termination
     * @throws InterruptedException if interrupted while waiting
     */
    boolean awaitTermination(long timeout, TimeUnit unit)
        throws InterruptedException;

}
Revision:	1.6
Committed:	Sun Aug 24 14:47:31 2003 UTC (20 years, 9 months ago) by dl
Branch:	MAIN
Changes since 1.5:	+5 -3 lines
Log Message:	Javadoc clarifications
#	User	Rev	Content
1	dl	1.1	/*
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			import java.util.List;
10
11			/**
12			* An executor that provides methods to manage termination. An
13			* <tt>ExecutorService</tt> can be shut down, which will cause it to
14			* stop accepting new tasks. After being shut down, the executor will
15			* eventually terminate, at which point no tasks are actively
16			* executing, no tasks are awaiting execution, and no new tasks can be
17			* submitted.
18			*
19			* <p>The <tt>Executors</tt> class provides factory methods for the
20	jozart	1.2	* executor services provided in <tt>java.util.concurrent</tt>.
21	dl	1.1	*
22			* @since 1.5
23			* @see Executors
24			*
25			* @spec JSR-166
26	dl	1.6	* @revised $Date: 2003/06/24 14:34:48 $
27	dl	1.4	* @editor $Author: dl $
28	dl	1.5	* @author Doug Lea
29	dl	1.1	*/
30			public interface ExecutorService extends Executor {
31
32			/**
33	dl	1.6	* Initiates an orderly shutdown in which previously submitted
34			* tasks are executed, but no new tasks will be
35			* accepted. Invocation has no additional effect if already shut
36			* down.
37	dl	1.1	*
38			*/
39			void shutdown();
40
41			/**
42			* Attempts to stop all actively executing tasks, halts the
43			* processing of waiting tasks, and returns a list of the tasks that were
44			* awaiting execution.
45			*
46			* <p>There are no guarantees beyond best-effort attempts to stop
47			* processing actively executing tasks. For example, typical
48			* implementations will cancel via {@link Thread#interrupt}, so if any
49			* tasks mask or fail to respond to interrupts, they may never terminate.
50			*
51			* @return list of tasks that never commenced execution
52			*/
53			List shutdownNow();
54
55			/**
56			* Returns <tt>true</tt> if this executor has been shut down.
57			*
58			* @return <tt>true</tt> if this executor has been shut down
59			*/
60			boolean isShutdown();
61
62			/**
63			* Returns <tt>true</tt> if all tasks have completed following shut down.
64			* Note that <tt>isTerminated</tt> is never <tt>true</tt> unless
65			* either <tt>shutdown</tt> or <tt>shutdownNow</tt> was called first.
66			*
67			* @return <tt>true</tt> if all tasks have completed following shut down
68			*/
69			boolean isTerminated();
70
71			/**
72			* Blocks until all tasks have completed execution after a shutdown
73			* request, or the timeout occurs, or the current thread is
74			* interrupted, whichever happens first.
75			*
76			* @param timeout the maximum time to wait
77			* @param unit the time unit of the timeout argument
78			* @return <tt>true</tt> if this executor terminated and <tt>false</tt>
79			* if the timeout elapsed before termination
80			* @throws InterruptedException if interrupted while waiting
81			*/
82			boolean awaitTermination(long timeout, TimeUnit unit)
83			throws InterruptedException;
84	dl	1.3
85	dl	1.1	}