Source code: edu/emory/mathcs/util/concurrent/ExecutorService.java
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 edu.emory.mathcs.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 * executor services provided in <tt>edu.emory.mathcs.util.concurrent</tt>.
21 *
22 * @since 1.5
23 * @see Executors
24 *
25 * @spec JSR-166
26 * @revised $Date: 2003/08/11 17:22:46 $
27 * @editor $Author: dawidk $
28 * @author Doug Lea
29 */
30 public interface ExecutorService extends Executor {
31
32 /**
33 * Initiates an orderly shutdown in which previously submitted tasks
34 * are executed, but no new tasks will be accepted.
35 *
36 */
37 void shutdown();
38
39 /**
40 * Attempts to stop all actively executing tasks, halts the
41 * processing of waiting tasks, and returns a list of the tasks that were
42 * awaiting execution.
43 *
44 * <p>There are no guarantees beyond best-effort attempts to stop
45 * processing actively executing tasks. For example, typical
46 * implementations will cancel via {@link Thread#interrupt}, so if any
47 * tasks mask or fail to respond to interrupts, they may never terminate.
48 *
49 * @return list of tasks that never commenced execution
50 */
51 List shutdownNow();
52
53 /**
54 * Returns <tt>true</tt> if this executor has been shut down.
55 *
56 * @return <tt>true</tt> if this executor has been shut down
57 */
58 boolean isShutdown();
59
60 /**
61 * Returns <tt>true</tt> if all tasks have completed following shut down.
62 * Note that <tt>isTerminated</tt> is never <tt>true</tt> unless
63 * either <tt>shutdown</tt> or <tt>shutdownNow</tt> was called first.
64 *
65 * @return <tt>true</tt> if all tasks have completed following shut down
66 */
67 boolean isTerminated();
68
69 /**
70 * Blocks until all tasks have completed execution after a shutdown
71 * request, or the timeout occurs, or the current thread is
72 * interrupted, whichever happens first.
73 *
74 * @param timeout the maximum time to wait
75 * @param unit the time unit of the timeout argument
76 * @return <tt>true</tt> if this executor terminated and <tt>false</tt>
77 * if the timeout elapsed before termination
78 * @throws InterruptedException if interrupted while waiting
79 */
80 boolean awaitTermination(long timeout, TimeUnit unit)
81 throws InterruptedException;
82
83 }