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线程池示例
在分析线程池之前，先看一个简单的线程池示例。
1 import java.util.concurrent.Executors;
2 import java.util.concurrent.ExecutorService;
3
4 public class ThreadPoolDemo1 {
5
6 public static void main(String[] args) {
7 // 创建一个可重用固定线程数的线程池
8 ExecutorService pool = Executors.newFixedThreadPool(2);
9 // 创建实现了Runnable接口对象，Thread对象当然也实现了Runnable接口
10 Thread ta = new MyThread();
11 Thread tb = new MyThread();
12 Thread tc = new MyThread();
13 Thread td = new MyThread();
14 Thread te = new MyThread();
15 // 将线程放入池中进行执行
16 pool.execute(ta);
17 pool.execute(tb);
18 pool.execute(tc);
19 pool.execute(td);
20 pool.execute(te);
21 // 关闭线程池
22 pool.shutdown();
23 }
24 }
25
26 class MyThread extends Thread {
27
28 @Override
29 public void run() {
30 System.out.println(Thread.currentThread().getName()+ " is running.");
31 }
32 }
运行结果：
pool-1-thread-1 is running. pool-1-thread-2 is running. pool-1-thread-1 is running. pool-1-thread-2 is running. pool-1-thread-1 is running.
示例中，包括了线程池的创建，将任务添加到线程池中，关闭线程池这3个主要的步骤。稍后，我们会从这3个方面来分析ThreadPoolExecutor。
参考代码(基于JDK1.7.0_40)
Executors完整源码
1 /*
2 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
3 *
4 *
5 *
6 *
7 *
8 *
9 *
10 *
11 *
12 *
13 *
14 *
15 *
16 *
17 *
18 *
19 *
20 *
21 *
22 *
23 */
24
25 /*
26 *
27 *
28 *
29 *
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.*;
38 import java.util.concurrent.atomic.AtomicInteger;
39 import java.security.AccessControlContext;
40 import java.security.AccessController;
41 import java.security.PrivilegedAction;
42 import java.security.PrivilegedExceptionAction;
43 import java.security.PrivilegedActionException;
44 import java.security.AccessControlException;
45 import sun.security.util.SecurityConstants;
46
47 /**
48 * Factory and utility methods for {@link Executor}, {@link
49 * ExecutorService}, {@link ScheduledExecutorService}, {@link
50 * ThreadFactory}, and {@link Callable} classes defined in this
51 * package. This class supports the following kinds of methods:
52 *
53 * <ul>
54 * <li> Methods that create and return an {@link ExecutorService}
55 * set up with commonly useful configuration settings.
56 * <li> Methods that create and return a {@link ScheduledExecutorService}
57 * set up with commonly useful configuration settings.
58 * <li> Methods that create and return a "wrapped" ExecutorService, that
59 * disables reconfiguration by making implementation-specific methods
60 * inaccessible.
61 * <li> Methods that create and return a {@link ThreadFactory}
62 * that sets newly created threads to a known state.
63 * <li> Methods that create and return a {@link Callable}
64 * out of other closure-like forms, so they can be used
65 * in execution methods requiring <tt>Callable</tt>.
66 * </ul>
67 *
68 * @since 1.5
69 * @author Doug Lea
70 */
71 public class Executors {
72
73 /**
74 * Creates a thread pool that reuses a fixed number of threads
75 * operating off a shared unbounded queue. At any point, at most
76 * <tt>nThreads</tt> threads will be active processing tasks.
77 * If additional tasks are submitted when all threads are active,
78 * they will wait in the queue until a thread is available.
79 * If any thread terminates due to a failure during execution
80 * prior to shutdown, a new one will take its place if needed to
81 * execute subsequent tasks. The threads in the pool will exist
82 * until it is explicitly {@link ExecutorService#shutdown shutdown}.
83 *
84 * @param nThreads the number of threads in the pool
85 * @return the newly created thread pool
86 * @throws IllegalArgumentException if {@code nThreads <= 0}
87 */
88 public static ExecutorService newFixedThreadPool(int nThreads) {
89 return new ThreadPoolExecutor(nThreads, nThreads,
90 0L, TimeUnit.MILLISECONDS,
91 new LinkedBlockingQueue<Runnable>());
92 }
93
94 /**
95 * Creates a thread pool that reuses a fixed number of threads
96 * operating off a shared unbounded queue, using the provided
97 * ThreadFactory to create new threads when needed. At any point,
98 * at most <tt>nThreads</tt> threads will be active processing
99 * tasks. If additional tasks are submitted when all threads are
100 * active, they will wait in the queue until a thread is
101 * available. If any thread terminates due to a failure during
102 * execution prior to shutdown, a new one will take its place if
103 * needed to execute subsequent tasks. The threads in the pool will
104 * exist until it is explicitly {@link ExecutorService#shutdown
105 * shutdown}.
106 *
107 * @param nThreads the number of threads in the pool
108 * @param threadFactory the factory to use when creating new threads
109 * @return the newly created thread pool
110 * @throws NullPointerException if threadFactory is null
111 * @throws IllegalArgumentException if {@code nThreads <= 0}
112 */
113 public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory) {
114 return new ThreadPoolExecutor(nThreads, nThreads,
115 0L, TimeUnit.MILLISECONDS,
116 new LinkedBlockingQueue<Runnable>(),
117 threadFactory);
118 }
119
120 /**
121 * Creates an Executor that uses a single worker thread operating
122 * off an unbounded queue. (Note however that if this single
123 * thread terminates due to a failure during execution prior to
124 * shutdown, a new one will take its place if needed to execute
125 * subsequent tasks.) Tasks are guaranteed to execute
126 * sequentially, and no more than one task will be active at any
127 * given time. Unlike the otherwise equivalent
128 * <tt>newFixedThreadPool(1)</tt> the returned executor is
129 * guaranteed not to be reconfigurable to use additional threads.
130 *
131 * @return the newly created single-threaded Executor
132 */
133 public static ExecutorService newSingleThreadExecutor() {
134 return new FinalizableDelegatedExecutorService
135 (new ThreadPoolExecutor(1, 1,
136 0L, TimeUnit.MILLISECONDS,
137 new LinkedBlockingQueue<Runnable>()));
138 }
139
140 /**
141 * Creates an Executor that uses a single worker thread operating
142 * off an unbounded queue, and uses the provided ThreadFactory to
143 * create a new thread when needed. Unlike the otherwise
144 * equivalent <tt>newFixedThreadPool(1, threadFactory)</tt> the
145 * returned executor is guaranteed not to be reconfigurable to use
146 * additional threads.
147 *
148 * @param threadFactory the factory to use when creating new
149 * threads
150 *
151 * @return the newly created single-threaded Executor
152 * @throws NullPointerException if threadFactory is null
153 */
154 public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory) {
155 return new FinalizableDelegatedExecutorService
156 (new ThreadPoolExecutor(1, 1,
157 0L, TimeUnit.MILLISECONDS,
158 new LinkedBlockingQueue<Runnable>(),
159 threadFactory));
160 }
161
162 /**
163 * Creates a thread pool that creates new threads as needed, but
164 * will reuse previously constructed threads when they are
165 * available. These pools will typically improve the performance
166 * of programs that execute many short-lived asynchronous tasks.
167 * Calls to <tt>execute</tt> will reuse previously constructed
168 * threads if available. If no existing thread is available, a new
169 * thread will be created and added to the pool. Threads that have
170 * not been used for sixty seconds are terminated and removed from
171 * the cache. Thus, a pool that remains idle for long enough will
172 * not consume any resources. Note that pools with similar
173 * properties but different details (for example, timeout parameters)
174 * may be created using {@link ThreadPoolExecutor} constructors.
175 *
176 * @return the newly created thread pool
177 */
178 public static ExecutorService newCachedThreadPool() {
179 return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
180 60L, TimeUnit.SECONDS,
181 new SynchronousQueue<Runnable>());
182 }
183
184 /**
185 * Creates a thread pool that creates new threads as needed, but
186 * will reuse previously constructed threads when they are
187 * available, and uses the provided
188 * ThreadFactory to create new threads when needed.
189 * @param threadFactory the factory to use when creating new threads
190 * @return the newly created thread pool
191 * @throws NullPointerException if threadFactory is null
192 */
193 public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory) {
194 return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
195 60L, TimeUnit.SECONDS,
196 new SynchronousQueue<Runnable>(),
197 threadFactory);
198 }
199
200 /**
201 * Creates a single-threaded executor that can schedule commands
202 * to run after a given delay, or to execute periodically.
203 * (Note however that if this single
204 * thread terminates due to a failure during execution prior to
205 * shutdown, a new one will take its place if needed to execute
206 * subsequent tasks.) Tasks are guaranteed to execute
207 * sequentially, and no more than one task will be active at any
208 * given time. Unlike the otherwise equivalent
209 * <tt>newScheduledThreadPool(1)</tt> the returned executor is
210 * guaranteed not to be reconfigurable to use additional threads.
211 * @return the newly created scheduled executor
212 */
213 public static ScheduledExecutorService newSingleThreadScheduledExecutor() {
214 return new DelegatedScheduledExecutorService
215 (new ScheduledThreadPoolExecutor(1));
216 }
217
218 /**
219 * Creates a single-threaded executor that can schedule commands
220 * to run after a given delay, or to execute periodically. (Note
221 * however that if this single thread terminates due to a failure
222 * during execution prior to shutdown, a new one will take its
223 * place if needed to execute subsequent tasks.) Tasks are
224 * guaranteed to execute sequentially, and no more than one task
225 * will be active at any given time. Unlike the otherwise
226 * equivalent <tt>newScheduledThreadPool(1, threadFactory)</tt>
227 * the returned executor is guaranteed not to be reconfigurable to
228 * use additional threads.
229 * @param threadFactory the factory to use when creating new
230 * threads
231 * @return a newly created scheduled executor
232 * @throws NullPointerException if threadFactory is null
233 */
234 public static ScheduledExecutorService newSingleThreadScheduledExecutor(ThreadFactory threadFactory) {
235 return new DelegatedScheduledExecutorService
236 (new ScheduledThreadPoolExecutor(1, threadFactory));
237 }
238
239 /**
240 * Creates a thread pool that can schedule commands to run after a
241 * given delay, or to execute periodically.
242 * @param corePoolSize the number of threads to keep in the pool,
243 * even if they are idle.
244 * @return a newly created scheduled thread pool
245 * @throws IllegalArgumentException if {@code corePoolSize < 0}
246 */
247 public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) {
248 return new ScheduledThreadPoolExecutor(corePoolSize);
249 }
250
251 /**
252 * Creates a thread pool that can schedule commands to run after a
253 * given delay, or to execute periodically.
254 * @param corePoolSize the number of threads to keep in the pool,
255 * even if they are idle.
256 * @param threadFactory the factory to use when the executor
257 * creates a new thread.
258 * @return a newly created scheduled thread pool
259 * @throws IllegalArgumentException if {@code corePoolSize < 0}
260 * @throws NullPointerException if threadFactory is null
261 */
262 public static ScheduledExecutorService newScheduledThreadPool(
263 int corePoolSize, ThreadFactory threadFactory) {
264 return new ScheduledThreadPoolExecutor(corePoolSize, threadFactory);
265 }
266
267
268 /**
269 * Returns an object that delegates all defined {@link
270 * ExecutorService} methods to the given executor, but not any
271 * other methods that might otherwise be accessible using
272 * casts. This provides a way to safely "freeze" configuration and
273 * disallow tuning of a given concrete implementation.
274 * @param executor the underlying implementation
275 * @return an <tt>ExecutorService</tt> instance
276 * @throws NullPointerException if executor null
277 */
278 public static ExecutorService unconfigurableExecutorService(ExecutorService executor) {
279 if (executor == null)
280 throw new NullPointerException();
281 return new DelegatedExecutorService(executor);
282 }
283
284 /**
285 * Returns an object that delegates all defined {@link
286 * ScheduledExecutorService} methods to the given executor, but
287 * not any other methods that might otherwise be accessible using
288 * casts. This provides a way to safely "freeze" configuration and
289 * disallow tuning of a given concrete implementation.
290 * @param executor the underlying implementation
291 * @return a <tt>ScheduledExecutorService</tt> instance
292 * @throws NullPointerException if executor null
293 */
294 public static ScheduledExecutorService unconfigurableScheduledExecutorService(ScheduledExecutorService executor) {
295 if (executor == null)
296 throw new NullPointerException();
297 return new DelegatedScheduledExecutorService(executor);
298 }
299
300 /**
301 * Returns a default thread factory used to create new threads.
302 * This factory creates all new threads used by an Executor in the
303 * same {@link ThreadGroup}. If there is a {@link
304 * java.lang.SecurityManager}, it uses the group of {@link
305 * System#getSecurityManager}, else the group of the thread
306 * invoking this <tt>defaultThreadFactory</tt> method. Each new
307 * thread is created as a non-daemon thread with priority set to
308 * the smaller of <tt>Thread.NORM_PRIORITY</tt> and the maximum
309 * priority permitted in the thread group. New threads have names
310 * accessible via {@link Thread#getName} of
311 * <em>pool-N-thread-M</em>, where <em>N</em> is the sequence
312 * number of this factory, and <em>M</em> is the sequence number
313 * of the thread created by this factory.
314 * @return a thread factory
315 */
316 public static ThreadFactory defaultThreadFactory() {
317 return new DefaultThreadFactory();
318 }
319
320 /**
321 * Returns a thread factory used to create new threads that
322 * have the same permissions as the current thread.
323 * This factory creates threads with the same settings as {@link
324 * Executors#defaultThreadFactory}, additionally setting the
325 * AccessControlContext and contextClassLoader of new threads to
326 * be the same as the thread invoking this
327 * <tt>privilegedThreadFactory</tt> method. A new
328 * <tt>privilegedThreadFactory</tt> can be created within an
329 * {@link AccessController#doPrivileged} action setting the
330 * current thread's access control context to create threads with
331 * the selected permission settings holding within that action.
332 *
333 * <p> Note that while tasks running within such threads will have
334 * the same access control and class loader settings as the
335 * current thread, they need not have the same {@link
336 * java.lang.ThreadLocal} or {@link
337 * java.lang.InheritableThreadLocal} values. If necessary,
338 * particular values of thread locals can be set or reset before
339 * any task runs in {@link ThreadPoolExecutor} subclasses using
340 * {@link ThreadPoolExecutor#beforeExecute}. Also, if it is
341 * necessary to initialize worker threads to have the same
342 * InheritableThreadLocal settings as some other designated
343 * thread, you can create a custom ThreadFactory in which that
344 * thread waits for and services requests to create others that
345 * will inherit its values.
346 *
347 * @return a thread factory
348 * @throws AccessControlException if the current access control
349 * context does not have permission to both get and set context
350 * class loader.
351 */
352 public static ThreadFactory privilegedThreadFactory() {
353 return new PrivilegedThreadFactory();
354 }
355
356 /**
357 * Returns a {@link Callable} object that, when
358 * called, runs the given task and returns the given result. This
359 * can be useful when applying methods requiring a
360 * <tt>Callable</tt> to an otherwise resultless action.
361 * @param task the task to run
362 * @param result the result to return
363 * @return a callable object
364 * @throws NullPointerException if task null
365 */
366 public static <T> Callable<T> callable(Runnable task, T result) {
367 if (task == null)
368 throw new NullPointerException();
369 return new RunnableAdapter<T>(task, result);
370 }
371
372 /**
373 * Returns a {@link Callable} object that, when
374 * called, runs the given task and returns <tt>null</tt>.
375 * @param task the task to run
376 * @return a callable object
377 * @throws NullPointerException if task null
378 */
379 public static Callable<Object> callable(Runnable task) {
380 if (task == null)
381 throw new NullPointerException();
382 return new RunnableAdapter<Object>(task, null);
383 }
384
385 /**
386 * Returns a {@link Callable} object that, when
387 * called, runs the given privileged action and returns its result.
388 * @param action the privileged action to run
389 * @return a callable object
390 * @throws NullPointerException if action null
391 */
392 public static Callable<Object> callable(final PrivilegedAction<?> action) {
393 if (action == null)
394 throw new NullPointerException();
395 return new Callable<Object>() {
396 public Object call() { return action.run(); }};
397 }
398
399 /**
400 * Returns a {@link Callable} object that, when
401 * called, runs the given privileged exception action and returns
402 * its result.
403 * @param action the privileged exception action to run
404 * @return a callable object
405 * @throws NullPointerException if action null
406 */
407 public static Callable<Object> callable(final PrivilegedExceptionAction<?> action) {
408 if (action == null)
409 throw new NullPointerException();
410 return new Callable<Object>() {
411 public Object call() throws Exception { return action.run(); }};
412 }
413
414 /**
415 * Returns a {@link Callable} object that will, when
416 * called, execute the given <tt>callable</tt> under the current
417 * access control context. This method should normally be
418 * invoked within an {@link AccessController#doPrivileged} action
419 * to create callables that will, if possible, execute under the
420 * selected permission settings holding within that action; or if
421 * not possible, throw an associated {@link
422 * AccessControlException}.
423 * @param callable the underlying task
424 * @return a callable object
425 * @throws NullPointerException if callable null
426 *
427 */
428 public static <T> Callable<T> privilegedCallable(Callable<T> callable) {
429 if (callable == null)
430 throw new NullPointerException();
431 return new PrivilegedCallable<T>(callable);
432 }
433
434 /**
435 * Returns a {@link Callable} object that will, when
436 * called, execute the given <tt>callable</tt> under the current
437 * access control context, with the current context class loader
438 * as the context class loader. This method should normally be
439 * invoked within an {@link AccessController#doPrivileged} action
440 * to create callables that will, if possible, execute under the
441 * selected permission settings holding within that action; or if
442 * not possible, throw an associated {@link
443 * AccessControlException}.
444 * @param callable the underlying task
445 *
446 * @return a callable object
447 * @throws NullPointerException if callable null
448 * @throws AccessControlException if the current access control
449 * context does not have permission to both set and get context
450 * class loader.
451 */
452 public static <T> Callable<T> privilegedCallableUsingCurrentClassLoader(Callable<T> callable) {
453 if (callable == null)
454 throw new NullPointerException();
455 return new PrivilegedCallableUsingCurrentClassLoader<T>(callable);
456 }
457
458 // Non-public classes supporting the public methods
459
460 /**
461 * A callable that runs given task and returns given result
462 */
463 static final class RunnableAdapter<T> implements Callable<T> {
464 final Runnable task;
465 final T result;
466 RunnableAdapter(Runnable task, T result) {
467 this.task = task;
468 this.result = result;
469 }
470 public T call() {
471 task.run();
472 return result;
473 }
474 }
475
476 /**
477 * A callable that runs under established access control settings
478 */
479 static final class PrivilegedCallable<T> implements Callable<T> {
480 private final Callable<T> task;
481 private final AccessControlContext acc;
482
483 PrivilegedCallable(Callable<T> task) {
484 this.task = task;
485 this.acc = AccessController.getContext();
486 }
487
488 public T call() throws Exception {
489 try {
490 return AccessController.doPrivileged(
491 new PrivilegedExceptionAction<T>() {
492 public T run() throws Exception {
493 return task.call();
494 }
495 }, acc);
496 } catch (PrivilegedActionException e) {
497 throw e.getException();
498 }
499 }
500 }
501
502 /**
503 * A callable that runs under established access control settings and
504 * current ClassLoader
505 */
506 static final class PrivilegedCallableUsingCurrentClassLoader<T> implements Callable<T> {
507 private final Callable<T> task;
508 private final AccessControlContext acc;
509 private final ClassLoader ccl;
510
511 PrivilegedCallableUsingCurrentClassLoader(Callable<T> task) {
512 SecurityManager sm = System.getSecurityManager();
513 if (sm != null) {
514 // Calls to getContextClassLoader from this class
515 // never trigger a security check, but we check
516 // whether our callers have this permission anyways.
517 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
518
519 // Whether setContextClassLoader turns out to be necessary
520 // or not, we fail fast if permission is not available.
521 sm.checkPermission(new RuntimePermission("setContextClassLoader"));
522 }
523 this.task = task;
524 this.acc = AccessController.getContext();
525 this.ccl = Thread.currentThread().getContextClassLoader();
526 }
527
528 public T call() throws Exception {
529 try {
530 return AccessController.doPrivileged(
531 new PrivilegedExceptionAction<T>() {
532 public T run() throws Exception {
533 Thread t = Thread.currentThread();
534 ClassLoader cl = t.getContextClassLoader();
535 if (ccl == cl) {
536 return task.call();
537 } else {
538 t.setContextClassLoader(ccl);
539 try {
540 return task.call();
541 } finally {
542 t.setContextClassLoader(cl);
543 }
544 }
545 }
546 }, acc);
547 } catch (PrivilegedActionException e) {
548 throw e.getException();
549 }
550 }
551 }
552
553 /**
554 * The default thread factory
555 */
556 static class DefaultThreadFactory implements ThreadFactory {
557 private static final AtomicInteger poolNumber = new AtomicInteger(1);
558 private final ThreadGroup group;
559 private final AtomicInteger threadNumber = new AtomicInteger(1);
560 private final String namePrefix;
561
562 DefaultThreadFactory() {
563 SecurityManager s = System.getSecurityManager();
564 group = (s != null) ? s.getThreadGroup() :
565 Thread.currentThread().getThreadGroup();
566 namePrefix = "pool-" +
567 poolNumber.getAndIncrement() +
568 "-thread-";
569 }
570
571 public Thread newThread(Runnable r) {
572 Thread t = new Thread(group, r,
573 namePrefix + threadNumber.getAndIncrement(),
574 0);
575 if (t.isDaemon())
576 t.setDaemon(false);
577 if (t.getPriority() != Thread.NORM_PRIORITY)
578 t.setPriority(Thread.NORM_PRIORITY);
579 return t;
580 }
581 }
582
583 /**
584 * Thread factory capturing access control context and class loader
585 */
586 static class PrivilegedThreadFactory extends DefaultThreadFactory {
587 private final AccessControlContext acc;
588 private final ClassLoader ccl;
589
590 PrivilegedThreadFactory() {
591 super();
592 SecurityManager sm = System.getSecurityManager();
593 if (sm != null) {
594 // Calls to getContextClassLoader from this class
595 // never trigger a security check, but we check
596 // whether our callers have this permission anyways.
597 sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
598
599 // Fail fast
600 sm.checkPermission(new RuntimePermission("setContextClassLoader"));
601 }
602 this.acc = AccessController.getContext();
603 this.ccl = Thread.currentThread().getContextClassLoader();
604 }
605
606 public Thread newThread(final Runnable r) {
607 return super.newThread(new Runnable() {
608 public void run() {
609 AccessController.doPrivileged(new PrivilegedAction<Void>() {
610 public Void run() {
611 Thread.currentThread().setContextClassLoader(ccl);
612 r.run();
613 return null;
614 }
615 }, acc);
616 }
617 });
618 }
619 }
620
621 /**
622 * A wrapper class that exposes only the ExecutorService methods
623 * of an ExecutorService implementation.
624 */
625 static class DelegatedExecutorService extends AbstractExecutorService {
626 private final ExecutorService e;
627 DelegatedExecutorService(ExecutorService executor) { e = executor; }
628 public void execute(Runnable command) { e.execute(command); }
629 public void shutdown() { e.shutdown(); }
630 public List<Runnable> shutdownNow() { return e.shutdownNow(); }
631 public boolean isShutdown() { return e.isShutdown(); }
632 public boolean isTerminated() { return e.isTerminated(); }
633 public boolean awaitTermination(long timeout, TimeUnit unit)
634 throws InterruptedException {
635 return e.awaitTermination(timeout, unit);
636 }
637 public Future<?> submit(Runnable task) {
638 return e.submit(task);
639 }
640 public <T> Future<T> submit(Callable<T> task) {
641 return e.submit(task);
642 }
643 public <T> Future<T> submit(Runnable task, T result) {
644 return e.submit(task, result);
645 }
646 public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
647 throws InterruptedException {
648 return e.invokeAll(tasks);
649 }
650 public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks,
651 long timeout, TimeUnit unit)
652 throws InterruptedException {
653 return e.invokeAll(tasks, timeout, unit);
654 }
655 public <T> T invokeAny(Collection<? extends Callable<T>> tasks)
656 throws InterruptedException, ExecutionException {
657 return e.invokeAny(tasks);
658 }
659 public <T> T invokeAny(Collection<? extends Callable<T>> tasks,
660 long timeout, TimeUnit unit)
661 throws InterruptedException, ExecutionException, TimeoutException {
662 return e.invokeAny(tasks, timeout, unit);
663 }
664 }
665
666 static class FinalizableDelegatedExecutorService
667 extends DelegatedExecutorService {
668 FinalizableDelegatedExecutorService(ExecutorService executor) {
669 super(executor);
670 }
671 protected void finalize() {
672 super.shutdown();
673 }
674 }
675
676 /**
677 * A wrapper class that exposes only the ScheduledExecutorService
678 * methods of a ScheduledExecutorService implementation.
679 */
680 static class DelegatedScheduledExecutorService
681 extends DelegatedExecutorService
682 implements ScheduledExecutorService {
683 private final ScheduledExecutorService e;
684 DelegatedScheduledExecutorService(ScheduledExecutorService executor) {
685 super(executor);
686 e = executor;
687 }
688 public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
689 return e.schedule(command, delay, unit);
690 }
691 public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) {
692 return e.schedule(callable, delay, unit);
693 }
694 public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) {
695 return e.scheduleAtFixedRate(command, initialDelay, period, unit);
696 }
697 public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) {
698 return e.scheduleWithFixedDelay(command, initialDelay, delay, unit);
699 }
700 }
701
702
703 /** Cannot instantiate. */
704 private Executors() {}
705 }