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;
import java.util.Collection;
import java.security.PrivilegedAction;
import java.security.PrivilegedExceptionAction;

/**
 * An <tt>Executor</tt> that provides methods to manage termination
 * and methods that can produce a {@link Future} for tracking
 * progress of one or more asynchronous tasks.
 * <p>
 *
 * 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> Method <tt>submit</tt> and related methods extend base method
 * <tt>execute</tt> by creating and returning a {@link Future} that
 * can be used to cancel execution and/or wait for completion.
 * Methods <tt>invokeAny</tt> and <tt>invokeAll</tt> perform the most
 * commonly useful forms of bulk execution, executing a collection of
 * tasks and then waiting for at least one, or all to complete. (Class
 * {@link ExecutorCompletionService} can be used to write customizable
 * versions of such methods.)
 *
 * <p>The {@link Executors} class provides factory methods for the
 * executor services provided in this package.
 *
 * @since 1.5
 * @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.
     * @throws SecurityException if a security manager exists and
     * shutting down this ExecutorService may manipulate threads that
     * the caller is not permitted to modify because it does not hold
     * {@link java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
     * or the security manager's <tt>checkAccess</tt>  method denies access.
     */
    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
     * @throws SecurityException if a security manager exists and
     * shutting down this ExecutorService may manipulate threads that
     * the caller is not permitted to modify because it does not hold
     * {@link java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
     * or the security manager's <tt>checkAccess</tt> method denies access.
     */
    List<Runnable> 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;


    /**
     * Submits a Runnable task for execution and returns a Future 
     * representing that task.
     *
     * @param task the task to submit
     * @param result the result to return upon completion
     * If you do not need a particular result, consider using
     * the form: <tt>Future&lt;?&gt; cancellationHandle = e.submit(task, null)</tt>.
     * @return a Future representing pending completion of the task,
     * and whose <tt>get()</tt> method will return the given value 
     * upon completion
     * @throws RejectedExecutionException if task cannot be scheduled
     * for execution
     */
    <T> Future<T> submit(Runnable task, T result);

    /**
     * Submits a value-returning task for execution and returns a Future
     * representing the pending results of the task.
     *
     * @param task the task to submit
     * @return a Future representing pending completion of the task
     * @throws RejectedExecutionException if task cannot be scheduled
     * for execution
     */
    <T> Future<T> submit(Callable<T> task);


    /**
     * Submits a privileged action for execution under the current 
     * access control context and returns a Future representing the 
     * pending result object of that action.
     *
     * @param action the action to submit
     * @return a Future representing pending completion of the action
     * @throws RejectedExecutionException if action cannot be scheduled
     * for execution
     */
    Future<Object> submit(PrivilegedAction action);

    /**
     * Submits a privileged exception action for execution under the current 
     * access control context and returns a Future representing the pending 
     * result object of that action.
     *
     * @param action the action to submit
     * @return a Future representing pending completion of the action
     * @throws RejectedExecutionException if action cannot be scheduled
     * for execution
     */
    Future<Object> submit(PrivilegedExceptionAction action);
    
    /**
     * Executes a Runnable task and blocks until it completes normally
     * or throws an exception.
     *
     * @param task the task to submit
     * @throws RejectedExecutionException if task cannot be scheduled
     * for execution
     * @throws ExecutionException if the task encountered an exception
     * while executing
     */
    void invoke(Runnable task) throws ExecutionException, InterruptedException;

    /**
     * Executes a value-returning task and blocks until it returns a
     * value or throws an exception.
     *
     * @param task the task to submit
     * @return a Future representing pending completion of the task
     * @throws RejectedExecutionException if task cannot be scheduled
     * for execution
     * @throws InterruptedException if interrupted while waiting for
     * completion
     * @throws ExecutionException if the task encountered an exception
     * while executing
     */
    <T> T invoke(Callable<T> task) throws ExecutionException, InterruptedException;

    /**
     * Executes the given tasks, returning when
     * all of them complete. 
     * Note that a <em>completed</em> task could have
     * terminated either normally or by throwing an exception.
     * @param tasks the collection of tasks
     * @param result value for each task to return upon completion.
     * If you do not need a particular result, consider using <tt>null</tt>.
     * @return A list of Futures representing the tasks, in the same
     * sequential order as as produced by the iterator for the given task list, each of which has
     * completed.
     * @throws InterruptedException if interrupted while waiting, in
     * which case unfinished tasks are cancelled.
     * @throws NullPointerException if tasks or any of its elements are <tt>null</tt>
     * @throws RejectedExecutionException if any task cannot be scheduled
     * for execution
     */
    <T> List<Future<T>> invokeAll(Collection<Runnable> tasks, T result)
        throws InterruptedException;

    /**
     * Executes the given tasks, returning normally
     * when all complete or the given timeout expires, whichever
     * happens first.
     * Upon return, tasks that have not completed are cancelled.
     * Note that a <em>completed</em> task could have
     * terminated either normally or by throwing an exception.
     * @param tasks the collection of tasks
     * @param result value for each task to return upon completion.
     * If you do not need a particular result, consider using <tt>null</tt>.
     * @param timeout the maximum time to wait
     * @return A list of Futures representing the tasks, in the same
     * sequential order as as produced by the iterator for the given task list. If the operation did
     * not time out, each task will have completed. If it did time
     * out, some of these tasks will not have completed.
     * @param unit the time unit of the timeout argument
     * @throws InterruptedException if interrupted while waiting, in
     * which case unfinished tasks are cancelled.
     * @throws NullPointerException if tasks, any of its elements, or unit are <tt>null</tt>
     * @throws RejectedExecutionException if any task cannot be scheduled
     * for execution
     */
    <T> List<Future<T>> invokeAll(Collection<Runnable> tasks, T result,
                               long timeout, TimeUnit unit) 
        throws InterruptedException;


    /**
     * Executes the given tasks, returning their results
     * when all complete.
     * Note that a <em>completed</em> task could have
     * terminated either normally or by throwing an exception.
     * @param tasks the collection of tasks
     * @return A list of Futures representing the tasks, in the same
     * sequential order as produced by the iterator for the given task list, each of which has
     * completed.
     * @throws InterruptedException if interrupted while waiting, in
     * which case unfinished tasks are cancelled.
     * @throws NullPointerException if tasks or any of its elements are <tt>null</tt>
     * @throws RejectedExecutionException if any task cannot be scheduled
     * for execution
     */

    <T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks)
        throws InterruptedException;

    /**
     * Executes the given tasks, returning their results
     * when all complete or the timeout expires, whichever happens first.
     * Upon return, tasks that have not completed are cancelled.
     * Note that a <em>completed</em> task could have
     * terminated either normally or by throwing an exception.
     * @param tasks the collection of tasks
     * @param timeout the maximum time to wait
     * @param unit the time unit of the timeout argument
     * @return A list of Futures representing the tasks, in the same
     * sequential order as as produced by the iterator for the given task list. If the operation did
     * not time out, each task will have completed. If it did time
     * out, some of thiese tasks will not have completed.
     * @throws InterruptedException if interrupted while waiting, in
     * which case unfinished tasks are cancelled.
     * @throws NullPointerException if tasks, any of its elements, or
     * unit are <tt>null</tt>
     * @throws RejectedExecutionException if any task cannot be scheduled
     * for execution
     */
    <T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks, 
                                long timeout, TimeUnit unit) 
        throws InterruptedException;


    /**
     * Executes the given tasks, returning the result
     * of one that has completed successfully (i.e., without throwing
     * an exception), if any do. Upon normal or exceptional return,
     * tasks that have not completed are cancelled.
     * @param tasks the collection of tasks
     * @return The result returned by one of the tasks.
     * @throws InterruptedException if interrupted while waiting
     * @throws NullPointerException if tasks or any of its elements
     * are <tt>null</tt>
     * @throws IllegalArgumentException if tasks empty
     * @throws ExecutionException if no task successfully completes
     * @throws RejectedExecutionException if tasks cannot be scheduled
     * for execution
     */

    <T> T invokeAny(Collection<Callable<T>> tasks)
        throws InterruptedException, ExecutionException;

    /**
     * Executes the given tasks, returning the result
     * of one that has completed successfully (i.e., without throwing
     * an exception), if any do before the given timeout elapses.
     * Upon normal or exceptional return, tasks that have not
     * completed are cancelled.
     * @param tasks the collection of tasks
     * @param timeout the maximum time to wait
     * @param unit the time unit of the timeout argument
     * @return The result returned by one of the tasks.
     * @throws InterruptedException if interrupted while waiting
     * @throws NullPointerException if tasks, any of its elements, or
     * unit are <tt>null</tt>
     * @throws TimeoutException if the given timeout elapses before
     * any task successfully completes
     * @throws ExecutionException if no task successfully completes
     * @throws RejectedExecutionException if tasks cannot be scheduled
     * for execution
     */
    <T> T invokeAny(Collection<Callable<T>> tasks, 
                    long timeout, TimeUnit unit) 
        throws InterruptedException, ExecutionException, TimeoutException;

    /**
     * Executes the given tasks, returning the given
     * result if one completes successfully (i.e., without
     * throwing an exception). Upon normal or exceptional
     * return, tasks that have not completed are cancelled.
     * @param tasks the collection of tasks
     * @param result the result to return upon successful completion
     * @return the given result
     * @throws InterruptedException if interrupted while waiting
     * @throws NullPointerException if tasks or any of its elements
     * are <tt>null</tt>
     * @throws IllegalArgumentException if tasks empty
     * @throws ExecutionException if no task successfully completes
     * @throws RejectedExecutionException if tasks cannot be scheduled
     * for execution
     */

    <T> T invokeAny(Collection<Runnable> tasks, T result)
        throws InterruptedException, ExecutionException;

    /**
     * Executes the given tasks, returning the given result
     * if one completes successfully (i.e., without throwing
     * an exception) before the given timeout elapses.
     * Upon normal or exceptional return, tasks that have not
     * completed are cancelled.
     * @param tasks the collection of tasks
     * @param result the result to return upon successful completion
     * @param timeout the maximum time to wait
     * @param unit the time unit of the timeout argument
     * @return the given result
     * @throws InterruptedException if interrupted while waiting
     * @throws NullPointerException if tasks, any of its elements, or
     * unit are <tt>null</tt>
     * @throws TimeoutException if the given timeout elapses before
     * any task successfully completes
     * @throws ExecutionException if no task successfully completes
     * @throws RejectedExecutionException if tasks cannot be scheduled
     * for execution
     */
    <T> T invokeAny(Collection<Runnable> tasks, T result,
                    long timeout, TimeUnit unit) 
        throws InterruptedException, ExecutionException, TimeoutException;


}
Revision:	1.17
Committed:	Fri Dec 19 14:42:25 2003 UTC (20 years, 5 months ago) by dl
Branch:	MAIN
Changes since 1.16:	+111 -96 lines
Log Message:	Documentation improvements
#	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	import java.util.List;
10	import java.util.Collection;
11	import java.security.PrivilegedAction;
12	import java.security.PrivilegedExceptionAction;
13
14	/**
15	* An <tt>Executor</tt> that provides methods to manage termination
16	* and methods that can produce a {@link Future} for tracking
17	* progress of one or more asynchronous tasks.
18	* <p>
19	*
20	* An <tt>ExecutorService</tt> can be shut down, which will cause it
21	* to stop accepting new tasks. After being shut down, the executor
22	* will eventually terminate, at which point no tasks are actively
23	* executing, no tasks are awaiting execution, and no new tasks can be
24	* submitted.
25	*
26	* <p> Method <tt>submit</tt> and related methods extend base method
27	* <tt>execute</tt> by creating and returning a {@link Future} that
28	* can be used to cancel execution and/or wait for completion.
29	* Methods <tt>invokeAny</tt> and <tt>invokeAll</tt> perform the most
30	* commonly useful forms of bulk execution, executing a collection of
31	* tasks and then waiting for at least one, or all to complete. (Class
32	* {@link ExecutorCompletionService} can be used to write customizable
33	* versions of such methods.)
34	*
35	* <p>The {@link Executors} class provides factory methods for the
36	* executor services provided in this package.
37	*
38	* @since 1.5
39	* @author Doug Lea
40	*/
41	public interface ExecutorService extends Executor {
42
43
44	/**
45	* Initiates an orderly shutdown in which previously submitted
46	* tasks are executed, but no new tasks will be
47	* accepted. Invocation has no additional effect if already shut
48	* down.
49	* @throws SecurityException if a security manager exists and
50	* shutting down this ExecutorService may manipulate threads that
51	* the caller is not permitted to modify because it does not hold
52	* {@link java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
53	* or the security manager's <tt>checkAccess</tt> method denies access.
54	*/
55	void shutdown();
56
57	/**
58	* Attempts to stop all actively executing tasks, halts the
59	* processing of waiting tasks, and returns a list of the tasks that were
60	* awaiting execution.
61	*
62	* <p>There are no guarantees beyond best-effort attempts to stop
63	* processing actively executing tasks. For example, typical
64	* implementations will cancel via {@link Thread#interrupt}, so if any
65	* tasks mask or fail to respond to interrupts, they may never terminate.
66	*
67	* @return list of tasks that never commenced execution
68	* @throws SecurityException if a security manager exists and
69	* shutting down this ExecutorService may manipulate threads that
70	* the caller is not permitted to modify because it does not hold
71	* {@link java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
72	* or the security manager's <tt>checkAccess</tt> method denies access.
73	*/
74	List<Runnable> shutdownNow();
75
76	/**
77	* Returns <tt>true</tt> if this executor has been shut down.
78	*
79	* @return <tt>true</tt> if this executor has been shut down
80	*/
81	boolean isShutdown();
82
83	/**
84	* Returns <tt>true</tt> if all tasks have completed following shut down.
85	* Note that <tt>isTerminated</tt> is never <tt>true</tt> unless
86	* either <tt>shutdown</tt> or <tt>shutdownNow</tt> was called first.
87	*
88	* @return <tt>true</tt> if all tasks have completed following shut down
89	*/
90	boolean isTerminated();
91
92	/**
93	* Blocks until all tasks have completed execution after a shutdown
94	* request, or the timeout occurs, or the current thread is
95	* interrupted, whichever happens first.
96	*
97	* @param timeout the maximum time to wait
98	* @param unit the time unit of the timeout argument
99	* @return <tt>true</tt> if this executor terminated and <tt>false</tt>
100	* if the timeout elapsed before termination
101	* @throws InterruptedException if interrupted while waiting
102	*/
103	boolean awaitTermination(long timeout, TimeUnit unit)
104	throws InterruptedException;
105
106
107	/**
108	* Submits a Runnable task for execution and returns a Future
109	* representing that task.
110	*
111	* @param task the task to submit
112	* @param result the result to return upon completion
113	* If you do not need a particular result, consider using
114	* the form: <tt>Future<?> cancellationHandle = e.submit(task, null)</tt>.
115	* @return a Future representing pending completion of the task,
116	* and whose <tt>get()</tt> method will return the given value
117	* upon completion
118	* @throws RejectedExecutionException if task cannot be scheduled
119	* for execution
120	*/
121	<T> Future<T> submit(Runnable task, T result);
122
123	/**
124	* Submits a value-returning task for execution and returns a Future
125	* representing the pending results of the task.
126	*
127	* @param task the task to submit
128	* @return a Future representing pending completion of the task
129	* @throws RejectedExecutionException if task cannot be scheduled
130	* for execution
131	*/
132	<T> Future<T> submit(Callable<T> task);
133
134
135	/**
136	* Submits a privileged action for execution under the current
137	* access control context and returns a Future representing the
138	* pending result object of that action.
139	*
140	* @param action the action to submit
141	* @return a Future representing pending completion of the action
142	* @throws RejectedExecutionException if action cannot be scheduled
143	* for execution
144	*/
145	Future<Object> submit(PrivilegedAction action);
146
147	/**
148	* Submits a privileged exception action for execution under the current
149	* access control context and returns a Future representing the pending
150	* result object of that action.
151	*
152	* @param action the action to submit
153	* @return a Future representing pending completion of the action
154	* @throws RejectedExecutionException if action cannot be scheduled
155	* for execution
156	*/
157	Future<Object> submit(PrivilegedExceptionAction action);
158
159	/**
160	* Executes a Runnable task and blocks until it completes normally
161	* or throws an exception.
162	*
163	* @param task the task to submit
164	* @throws RejectedExecutionException if task cannot be scheduled
165	* for execution
166	* @throws ExecutionException if the task encountered an exception
167	* while executing
168	*/
169	void invoke(Runnable task) throws ExecutionException, InterruptedException;
170
171	/**
172	* Executes a value-returning task and blocks until it returns a
173	* value or throws an exception.
174	*
175	* @param task the task to submit
176	* @return a Future representing pending completion of the task
177	* @throws RejectedExecutionException if task cannot be scheduled
178	* for execution
179	* @throws InterruptedException if interrupted while waiting for
180	* completion
181	* @throws ExecutionException if the task encountered an exception
182	* while executing
183	*/
184	<T> T invoke(Callable<T> task) throws ExecutionException, InterruptedException;
185
186	/**
187	* Executes the given tasks, returning when
188	* all of them complete.
189	* Note that a <em>completed</em> task could have
190	* terminated either normally or by throwing an exception.
191	* @param tasks the collection of tasks
192	* @param result value for each task to return upon completion.
193	* If you do not need a particular result, consider using <tt>null</tt>.
194	* @return A list of Futures representing the tasks, in the same
195	* sequential order as as produced by the iterator for the given task list, each of which has
196	* completed.
197	* @throws InterruptedException if interrupted while waiting, in
198	* which case unfinished tasks are cancelled.
199	* @throws NullPointerException if tasks or any of its elements are <tt>null</tt>
200	* @throws RejectedExecutionException if any task cannot be scheduled
201	* for execution
202	*/
203	<T> List<Future<T>> invokeAll(Collection<Runnable> tasks, T result)
204	throws InterruptedException;
205
206	/**
207	* Executes the given tasks, returning normally
208	* when all complete or the given timeout expires, whichever
209	* happens first.
210	* Upon return, tasks that have not completed are cancelled.
211	* Note that a <em>completed</em> task could have
212	* terminated either normally or by throwing an exception.
213	* @param tasks the collection of tasks
214	* @param result value for each task to return upon completion.
215	* If you do not need a particular result, consider using <tt>null</tt>.
216	* @param timeout the maximum time to wait
217	* @return A list of Futures representing the tasks, in the same
218	* sequential order as as produced by the iterator for the given task list. If the operation did
219	* not time out, each task will have completed. If it did time
220	* out, some of these tasks will not have completed.
221	* @param unit the time unit of the timeout argument
222	* @throws InterruptedException if interrupted while waiting, in
223	* which case unfinished tasks are cancelled.
224	* @throws NullPointerException if tasks, any of its elements, or unit are <tt>null</tt>
225	* @throws RejectedExecutionException if any task cannot be scheduled
226	* for execution
227	*/
228	<T> List<Future<T>> invokeAll(Collection<Runnable> tasks, T result,
229	long timeout, TimeUnit unit)
230	throws InterruptedException;
231
232
233	/**
234	* Executes the given tasks, returning their results
235	* when all complete.
236	* Note that a <em>completed</em> task could have
237	* terminated either normally or by throwing an exception.
238	* @param tasks the collection of tasks
239	* @return A list of Futures representing the tasks, in the same
240	* sequential order as produced by the iterator for the given task list, each of which has
241	* completed.
242	* @throws InterruptedException if interrupted while waiting, in
243	* which case unfinished tasks are cancelled.
244	* @throws NullPointerException if tasks or any of its elements are <tt>null</tt>
245	* @throws RejectedExecutionException if any task cannot be scheduled
246	* for execution
247	*/
248
249	<T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks)
250	throws InterruptedException;
251
252	/**
253	* Executes the given tasks, returning their results
254	* when all complete or the timeout expires, whichever happens first.
255	* Upon return, tasks that have not completed are cancelled.
256	* Note that a <em>completed</em> task could have
257	* terminated either normally or by throwing an exception.
258	* @param tasks the collection of tasks
259	* @param timeout the maximum time to wait
260	* @param unit the time unit of the timeout argument
261	* @return A list of Futures representing the tasks, in the same
262	* sequential order as as produced by the iterator for the given task list. If the operation did
263	* not time out, each task will have completed. If it did time
264	* out, some of thiese tasks will not have completed.
265	* @throws InterruptedException if interrupted while waiting, in
266	* which case unfinished tasks are cancelled.
267	* @throws NullPointerException if tasks, any of its elements, or
268	* unit are <tt>null</tt>
269	* @throws RejectedExecutionException if any task cannot be scheduled
270	* for execution
271	*/
272	<T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks,
273	long timeout, TimeUnit unit)
274	throws InterruptedException;
275
276
277	/**
278	* Executes the given tasks, returning the result
279	* of one that has completed successfully (i.e., without throwing
280	* an exception), if any do. Upon normal or exceptional return,
281	* tasks that have not completed are cancelled.
282	* @param tasks the collection of tasks
283	* @return The result returned by one of the tasks.
284	* @throws InterruptedException if interrupted while waiting
285	* @throws NullPointerException if tasks or any of its elements
286	* are <tt>null</tt>
287	* @throws IllegalArgumentException if tasks empty
288	* @throws ExecutionException if no task successfully completes
289	* @throws RejectedExecutionException if tasks cannot be scheduled
290	* for execution
291	*/
292
293	<T> T invokeAny(Collection<Callable<T>> tasks)
294	throws InterruptedException, ExecutionException;
295
296	/**
297	* Executes the given tasks, returning the result
298	* of one that has completed successfully (i.e., without throwing
299	* an exception), if any do before the given timeout elapses.
300	* Upon normal or exceptional return, tasks that have not
301	* completed are cancelled.
302	* @param tasks the collection of tasks
303	* @param timeout the maximum time to wait
304	* @param unit the time unit of the timeout argument
305	* @return The result returned by one of the tasks.
306	* @throws InterruptedException if interrupted while waiting
307	* @throws NullPointerException if tasks, any of its elements, or
308	* unit are <tt>null</tt>
309	* @throws TimeoutException if the given timeout elapses before
310	* any task successfully completes
311	* @throws ExecutionException if no task successfully completes
312	* @throws RejectedExecutionException if tasks cannot be scheduled
313	* for execution
314	*/
315	<T> T invokeAny(Collection<Callable<T>> tasks,
316	long timeout, TimeUnit unit)
317	throws InterruptedException, ExecutionException, TimeoutException;
318
319	/**
320	* Executes the given tasks, returning the given
321	* result if one completes successfully (i.e., without
322	* throwing an exception). Upon normal or exceptional
323	* return, tasks that have not completed are cancelled.
324	* @param tasks the collection of tasks
325	* @param result the result to return upon successful completion
326	* @return the given result
327	* @throws InterruptedException if interrupted while waiting
328	* @throws NullPointerException if tasks or any of its elements
329	* are <tt>null</tt>
330	* @throws IllegalArgumentException if tasks empty
331	* @throws ExecutionException if no task successfully completes
332	* @throws RejectedExecutionException if tasks cannot be scheduled
333	* for execution
334	*/
335
336	<T> T invokeAny(Collection<Runnable> tasks, T result)
337	throws InterruptedException, ExecutionException;
338
339	/**
340	* Executes the given tasks, returning the given result
341	* if one completes successfully (i.e., without throwing
342	* an exception) before the given timeout elapses.
343	* Upon normal or exceptional return, tasks that have not
344	* completed are cancelled.
345	* @param tasks the collection of tasks
346	* @param result the result to return upon successful completion
347	* @param timeout the maximum time to wait
348	* @param unit the time unit of the timeout argument
349	* @return the given result
350	* @throws InterruptedException if interrupted while waiting
351	* @throws NullPointerException if tasks, any of its elements, or
352	* unit are <tt>null</tt>
353	* @throws TimeoutException if the given timeout elapses before
354	* any task successfully completes
355	* @throws ExecutionException if no task successfully completes
356	* @throws RejectedExecutionException if tasks cannot be scheduled
357	* for execution
358	*/
359	<T> T invokeAny(Collection<Runnable> tasks, T result,
360	long timeout, TimeUnit unit)
361	throws InterruptedException, ExecutionException, TimeoutException;
362
363
364	}