01: /*
02: File: Executor.java
03:
04: Originally written by Doug Lea and released into the public domain.
05: This may be used for any purposes whatsoever without acknowledgment.
06: Thanks for the assistance and support of Sun Microsystems Labs,
07: and everyone contributing, testing, and using this code.
08:
09: History:
10: Date Who What
11: 19Jun1998 dl Create public version
12: */
13:
14: package EDU.oswego.cs.dl.util.concurrent;
15:
16: /**
17: * Interface for objects that execute Runnables,
18: * as well as various objects that can be wrapped
19: * as Runnables.
20: * The main reason to use Executor throughout a program or
21: * subsystem is to provide flexibility: You can easily
22: * change from using thread-per-task to using pools or
23: * queuing, without needing to change most of your code that
24: * generates tasks.
25: * <p>
26: * The general intent is that execution be asynchronous,
27: * or at least independent of the caller. For example,
28: * one of the simplest implementations of <code>execute</code>
29: * (as performed in ThreadedExecutor)
30: * is <code>new Thread(command).start();</code>.
31: * However, this interface allows implementations that instead
32: * employ queueing or pooling, or perform additional
33: * bookkeeping.
34: * <p>
35: *
36: * <p>[<a href="http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html"> Introduction to this package. </a>]
37: **/
38: public interface Executor {
39: /**
40: * Execute the given command. This method is guaranteed
41: * only to arrange for execution, that may actually
42: * occur sometime later; for example in a new
43: * thread. However, in fully generic use, callers
44: * should be prepared for execution to occur in
45: * any fashion at all, including immediate direct
46: * execution.
47: * <p>
48: * The method is defined not to throw
49: * any checked exceptions during execution of the command. Generally,
50: * any problems encountered will be asynchronous and
51: * so must be dealt with via callbacks or error handler
52: * objects. If necessary, any context-dependent
53: * catastrophic errors encountered during
54: * actions that arrange for execution could be accompanied
55: * by throwing context-dependent unchecked exceptions.
56: * <p>
57: * However, the method does throw InterruptedException:
58: * It will fail to arrange for execution
59: * if the current thread is currently interrupted.
60: * Further, the general contract of the method is to avoid,
61: * suppress, or abort execution if interruption is detected
62: * in any controllable context surrounding execution.
63: **/
64: public void execute(Runnable command) throws InterruptedException;
65:
66: }
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