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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

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java/pkg/java/util/concurrent/ExecutorService.java+370−0
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1+/*
2+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3+ *
4+ * This code is free software; you can redistribute it and/or modify it
5+ * under the terms of the GNU General Public License version 2 only, as
6+ * published by the Free Software Foundation. Oracle designates this
7+ * particular file as subject to the "Classpath" exception as provided
8+ * by Oracle in the LICENSE file that accompanied this code.
9+ *
10+ * This code is distributed in the hope that it will be useful, but WITHOUT
11+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13+ * version 2 for more details (a copy is included in the LICENSE file that
14+ * accompanied this code).
15+ *
16+ * You should have received a copy of the GNU General Public License version
17+ * 2 along with this work; if not, write to the Free Software Foundation,
18+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19+ *
20+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21+ * or visit www.oracle.com if you need additional information or have any
22+ * questions.
23+ */
24+
25+/*
26+ * This file is available under and governed by the GNU General Public
27+ * License version 2 only, as published by the Free Software Foundation.
28+ * However, the following notice accompanied the original version of this
29+ * file:
30+ *
31+ * Written by Doug Lea with assistance from members of JCP JSR-166
32+ * Expert Group and released to the public domain, as explained at
33+ * http://creativecommons.org/publicdomain/zero/1.0/
34+ */
35+
36+package java.util.concurrent;
37+import java.util.List;
38+import java.util.Collection;
39+import java.security.PrivilegedAction;
40+import java.security.PrivilegedExceptionAction;
41+
42+/**
43+ * An {@link Executor} that provides methods to manage termination and
44+ * methods that can produce a {@link Future} for tracking progress of
45+ * one or more asynchronous tasks.
46+ *
47+ * <p> An <tt>ExecutorService</tt> can be shut down, which will cause
48+ * it to reject new tasks. Two different methods are provided for
49+ * shutting down an <tt>ExecutorService</tt>. The {@link #shutdown}
50+ * method will allow previously submitted tasks to execute before
51+ * terminating, while the {@link #shutdownNow} method prevents waiting
52+ * tasks from starting and attempts to stop currently executing tasks.
53+ * Upon termination, an executor has no tasks actively executing, no
54+ * tasks awaiting execution, and no new tasks can be submitted. An
55+ * unused <tt>ExecutorService</tt> should be shut down to allow
56+ * reclamation of its resources.
57+ *
58+ * <p> Method <tt>submit</tt> extends base method {@link
59+ * Executor#execute} by creating and returning a {@link Future} that
60+ * can be used to cancel execution and/or wait for completion.
61+ * Methods <tt>invokeAny</tt> and <tt>invokeAll</tt> perform the most
62+ * commonly useful forms of bulk execution, executing a collection of
63+ * tasks and then waiting for at least one, or all, to
64+ * complete. (Class {@link ExecutorCompletionService} can be used to
65+ * write customized variants of these methods.)
66+ *
67+ * <p>The {@link Executors} class provides factory methods for the
68+ * executor services provided in this package.
69+ *
70+ * <h3>Usage Examples</h3>
71+ *
72+ * Here is a sketch of a network service in which threads in a thread
73+ * pool service incoming requests. It uses the preconfigured {@link
74+ * Executors#newFixedThreadPool} factory method:
75+ *
76+ * <pre>
77+ * class NetworkService implements Runnable {
78+ * private final ServerSocket serverSocket;
79+ * private final ExecutorService pool;
80+ *
81+ * public NetworkService(int port, int poolSize)
82+ * throws IOException {
83+ * serverSocket = new ServerSocket(port);
84+ * pool = Executors.newFixedThreadPool(poolSize);
85+ * }
86+ *
87+ * public void run() { // run the service
88+ * try {
89+ * for (;;) {
90+ * pool.execute(new Handler(serverSocket.accept()));
91+ * }
92+ * } catch (IOException ex) {
93+ * pool.shutdown();
94+ * }
95+ * }
96+ * }
97+ *
98+ * class Handler implements Runnable {
99+ * private final Socket socket;
100+ * Handler(Socket socket) { this.socket = socket; }
101+ * public void run() {
102+ * // read and service request on socket
103+ * }
104+ * }
105+ * </pre>
106+ *
107+ * The following method shuts down an <tt>ExecutorService</tt> in two phases,
108+ * first by calling <tt>shutdown</tt> to reject incoming tasks, and then
109+ * calling <tt>shutdownNow</tt>, if necessary, to cancel any lingering tasks:
110+ *
111+ * <pre>
112+ * void shutdownAndAwaitTermination(ExecutorService pool) {
113+ * pool.shutdown(); // Disable new tasks from being submitted
114+ * try {
115+ * // Wait a while for existing tasks to terminate
116+ * if (!pool.awaitTermination(60, TimeUnit.SECONDS)) {
117+ * pool.shutdownNow(); // Cancel currently executing tasks
118+ * // Wait a while for tasks to respond to being cancelled
119+ * if (!pool.awaitTermination(60, TimeUnit.SECONDS))
120+ * System.err.println("Pool did not terminate");
121+ * }
122+ * } catch (InterruptedException ie) {
123+ * // (Re-)Cancel if current thread also interrupted
124+ * pool.shutdownNow();
125+ * // Preserve interrupt status
126+ * Thread.currentThread().interrupt();
127+ * }
128+ * }
129+ * </pre>
130+ *
131+ * <p>Memory consistency effects: Actions in a thread prior to the
132+ * submission of a {@code Runnable} or {@code Callable} task to an
133+ * {@code ExecutorService}
134+ * <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a>
135+ * any actions taken by that task, which in turn <i>happen-before</i> the
136+ * result is retrieved via {@code Future.get()}.
137+ *
138+ * @since 1.5
139+ * @author Doug Lea
140+ */
141+public interface ExecutorService extends Executor {
142+
143+ /**
144+ * Initiates an orderly shutdown in which previously submitted
145+ * tasks are executed, but no new tasks will be accepted.
146+ * Invocation has no additional effect if already shut down.
147+ *
148+ * <p>This method does not wait for previously submitted tasks to
149+ * complete execution. Use {@link #awaitTermination awaitTermination}
150+ * to do that.
151+ *
152+ * @throws SecurityException if a security manager exists and
153+ * shutting down this ExecutorService may manipulate
154+ * threads that the caller is not permitted to modify
155+ * because it does not hold {@link
156+ * java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
157+ * or the security manager's <tt>checkAccess</tt> method
158+ * denies access.
159+ */
160+ void shutdown();
161+
162+ /**
163+ * Attempts to stop all actively executing tasks, halts the
164+ * processing of waiting tasks, and returns a list of the tasks
165+ * that were awaiting execution.
166+ *
167+ * <p>This method does not wait for actively executing tasks to
168+ * terminate. Use {@link #awaitTermination awaitTermination} to
169+ * do that.
170+ *
171+ * <p>There are no guarantees beyond best-effort attempts to stop
172+ * processing actively executing tasks. For example, typical
173+ * implementations will cancel via {@link Thread#interrupt}, so any
174+ * task that fails to respond to interrupts may never terminate.
175+ *
176+ * @return list of tasks that never commenced execution
177+ * @throws SecurityException if a security manager exists and
178+ * shutting down this ExecutorService may manipulate
179+ * threads that the caller is not permitted to modify
180+ * because it does not hold {@link
181+ * java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
182+ * or the security manager's <tt>checkAccess</tt> method
183+ * denies access.
184+ */
185+ List<Runnable> shutdownNow();
186+
187+ /**
188+ * Returns <tt>true</tt> if this executor has been shut down.
189+ *
190+ * @return <tt>true</tt> if this executor has been shut down
191+ */
192+ boolean isShutdown();
193+
194+ /**
195+ * Returns <tt>true</tt> if all tasks have completed following shut down.
196+ * Note that <tt>isTerminated</tt> is never <tt>true</tt> unless
197+ * either <tt>shutdown</tt> or <tt>shutdownNow</tt> was called first.
198+ *
199+ * @return <tt>true</tt> if all tasks have completed following shut down
200+ */
201+ boolean isTerminated();
202+
203+ /**
204+ * Blocks until all tasks have completed execution after a shutdown
205+ * request, or the timeout occurs, or the current thread is
206+ * interrupted, whichever happens first.
207+ *
208+ * @param timeout the maximum time to wait
209+ * @param unit the time unit of the timeout argument
210+ * @return <tt>true</tt> if this executor terminated and
211+ * <tt>false</tt> if the timeout elapsed before termination
212+ * @throws InterruptedException if interrupted while waiting
213+ */
214+ boolean awaitTermination(long timeout, TimeUnit unit)
215+ throws InterruptedException;
216+
217+
218+ /**
219+ * Submits a value-returning task for execution and returns a
220+ * Future representing the pending results of the task. The
221+ * Future's <tt>get</tt> method will return the task's result upon
222+ * successful completion.
223+ *
224+ * <p>
225+ * If you would like to immediately block waiting
226+ * for a task, you can use constructions of the form
227+ * <tt>result = exec.submit(aCallable).get();</tt>
228+ *
229+ * <p> Note: The {@link Executors} class includes a set of methods
230+ * that can convert some other common closure-like objects,
231+ * for example, {@link java.security.PrivilegedAction} to
232+ * {@link Callable} form so they can be submitted.
233+ *
234+ * @param task the task to submit
235+ * @return a Future representing pending completion of the task
236+ * @throws RejectedExecutionException if the task cannot be
237+ * scheduled for execution
238+ * @throws NullPointerException if the task is null
239+ */
240+ <T> Future<T> submit(Callable<T> task);
241+
242+ /**
243+ * Submits a Runnable task for execution and returns a Future
244+ * representing that task. The Future's <tt>get</tt> method will
245+ * return the given result upon successful completion.
246+ *
247+ * @param task the task to submit
248+ * @param result the result to return
249+ * @return a Future representing pending completion of the task
250+ * @throws RejectedExecutionException if the task cannot be
251+ * scheduled for execution
252+ * @throws NullPointerException if the task is null
253+ */
254+ <T> Future<T> submit(Runnable task, T result);
255+
256+ /**
257+ * Submits a Runnable task for execution and returns a Future
258+ * representing that task. The Future's <tt>get</tt> method will
259+ * return <tt>null</tt> upon <em>successful</em> completion.
260+ *
261+ * @param task the task to submit
262+ * @return a Future representing pending completion of the task
263+ * @throws RejectedExecutionException if the task cannot be
264+ * scheduled for execution
265+ * @throws NullPointerException if the task is null
266+ */
267+ Future<?> submit(Runnable task);
268+
269+ /**
270+ * Executes the given tasks, returning a list of Futures holding
271+ * their status and results when all complete.
272+ * {@link Future#isDone} is <tt>true</tt> for each
273+ * element of the returned list.
274+ * Note that a <em>completed</em> task could have
275+ * terminated either normally or by throwing an exception.
276+ * The results of this method are undefined if the given
277+ * collection is modified while this operation is in progress.
278+ *
279+ * @param tasks the collection of tasks
280+ * @return A list of Futures representing the tasks, in the same
281+ * sequential order as produced by the iterator for the
282+ * given task list, each of which has completed.
283+ * @throws InterruptedException if interrupted while waiting, in
284+ * which case unfinished tasks are cancelled.
285+ * @throws NullPointerException if tasks or any of its elements are <tt>null</tt>
286+ * @throws RejectedExecutionException if any task cannot be
287+ * scheduled for execution
288+ */
289+
290+ <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
291+ throws InterruptedException;
292+
293+ /**
294+ * Executes the given tasks, returning a list of Futures holding
295+ * their status and results
296+ * when all complete or the timeout expires, whichever happens first.
297+ * {@link Future#isDone} is <tt>true</tt> for each
298+ * element of the returned list.
299+ * Upon return, tasks that have not completed are cancelled.
300+ * Note that a <em>completed</em> task could have
301+ * terminated either normally or by throwing an exception.
302+ * The results of this method are undefined if the given
303+ * collection is modified while this operation is in progress.
304+ *
305+ * @param tasks the collection of tasks
306+ * @param timeout the maximum time to wait
307+ * @param unit the time unit of the timeout argument
308+ * @return a list of Futures representing the tasks, in the same
309+ * sequential order as produced by the iterator for the
310+ * given task list. If the operation did not time out,
311+ * each task will have completed. If it did time out, some
312+ * of these tasks will not have completed.
313+ * @throws InterruptedException if interrupted while waiting, in
314+ * which case unfinished tasks are cancelled
315+ * @throws NullPointerException if tasks, any of its elements, or
316+ * unit are <tt>null</tt>
317+ * @throws RejectedExecutionException if any task cannot be scheduled
318+ * for execution
319+ */
320+ <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks,
321+ long timeout, TimeUnit unit)
322+ throws InterruptedException;
323+
324+ /**
325+ * Executes the given tasks, returning the result
326+ * of one that has completed successfully (i.e., without throwing
327+ * an exception), if any do. Upon normal or exceptional return,
328+ * tasks that have not completed are cancelled.
329+ * The results of this method are undefined if the given
330+ * collection is modified while this operation is in progress.
331+ *
332+ * @param tasks the collection of tasks
333+ * @return the result returned by one of the tasks
334+ * @throws InterruptedException if interrupted while waiting
335+ * @throws NullPointerException if tasks or any element task
336+ * subject to execution is <tt>null</tt>
337+ * @throws IllegalArgumentException if tasks is empty
338+ * @throws ExecutionException if no task successfully completes
339+ * @throws RejectedExecutionException if tasks cannot be scheduled
340+ * for execution
341+ */
342+ <T> T invokeAny(Collection<? extends Callable<T>> tasks)
343+ throws InterruptedException, ExecutionException;
344+
345+ /**
346+ * Executes the given tasks, returning the result
347+ * of one that has completed successfully (i.e., without throwing
348+ * an exception), if any do before the given timeout elapses.
349+ * Upon normal or exceptional return, tasks that have not
350+ * completed are cancelled.
351+ * The results of this method are undefined if the given
352+ * collection is modified while this operation is in progress.
353+ *
354+ * @param tasks the collection of tasks
355+ * @param timeout the maximum time to wait
356+ * @param unit the time unit of the timeout argument
357+ * @return the result returned by one of the tasks.
358+ * @throws InterruptedException if interrupted while waiting
359+ * @throws NullPointerException if tasks, or unit, or any element
360+ * task subject to execution is <tt>null</tt>
361+ * @throws TimeoutException if the given timeout elapses before
362+ * any task successfully completes
363+ * @throws ExecutionException if no task successfully completes
364+ * @throws RejectedExecutionException if tasks cannot be scheduled
365+ * for execution
366+ */
367+ <T> T invokeAny(Collection<? extends Callable<T>> tasks,
368+ long timeout, TimeUnit unit)
369+ throws InterruptedException, ExecutionException, TimeoutException;
370+}