1 |
/* |
2 |
* Written by Doug Lea with assistance from members of JCP JSR-166 |
3 |
* Expert Group and released to the public domain, as explained at |
4 |
* http://creativecommons.org/licenses/publicdomain |
5 |
*/ |
6 |
|
7 |
package java.util.concurrent; |
8 |
import java.util.*; |
9 |
import java.util.concurrent.atomic.AtomicInteger; |
10 |
import java.security.AccessControlContext; |
11 |
import java.security.AccessController; |
12 |
import java.security.PrivilegedAction; |
13 |
import java.security.PrivilegedExceptionAction; |
14 |
import java.security.AccessControlException; |
15 |
|
16 |
/** |
17 |
* Factory and utility methods for {@link Executor}, {@link |
18 |
* ExecutorService}, {@link ScheduledExecutorService}, {@link |
19 |
* ThreadFactory}, and {@link Callable} classes defined in this |
20 |
* package. This class supports the following kinds of methods: |
21 |
* |
22 |
* <ul> |
23 |
* <li> Methods that create and return an {@link ExecutorService} |
24 |
* set up with commonly useful configuration settings. |
25 |
* <li> Methods that create and return a {@link ScheduledExecutorService} |
26 |
* set up with commonly useful configuration settings. |
27 |
* <li> Methods that create and return a "wrapped" ExecutorService, that |
28 |
* disables reconfiguration by making implementation-specific methods |
29 |
* inaccessible. |
30 |
* <li> Methods that create and return a {@link ThreadFactory} |
31 |
* that sets newly created threads to a known state. |
32 |
* <li> Methods that create and return a {@link Callable} |
33 |
* out of other closure-like forms, so they can be used |
34 |
* in execution methods requiring <tt>Callable</tt>. |
35 |
* </ul> |
36 |
* |
37 |
* @since 1.5 |
38 |
* @author Doug Lea |
39 |
*/ |
40 |
public class Executors { |
41 |
|
42 |
/** |
43 |
* Creates a thread pool that reuses a fixed set of threads |
44 |
* operating off a shared unbounded queue. If any thread |
45 |
* terminates due to a failure during execution prior to shutdown, |
46 |
* a new one will take its place if needed to execute subsequent |
47 |
* tasks. |
48 |
* |
49 |
* @param nThreads the number of threads in the pool |
50 |
* @return the newly created thread pool |
51 |
*/ |
52 |
public static ExecutorService newFixedThreadPool(int nThreads) { |
53 |
return new ThreadPoolExecutor(nThreads, nThreads, |
54 |
0L, TimeUnit.MILLISECONDS, |
55 |
new LinkedBlockingQueue<Runnable>()); |
56 |
} |
57 |
|
58 |
/** |
59 |
* Creates a thread pool that reuses a fixed set of threads |
60 |
* operating off a shared unbounded queue, using the provided |
61 |
* ThreadFactory to create new threads when needed. |
62 |
* |
63 |
* @param nThreads the number of threads in the pool |
64 |
* @param threadFactory the factory to use when creating new threads |
65 |
* @return the newly created thread pool |
66 |
*/ |
67 |
public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory) { |
68 |
return new ThreadPoolExecutor(nThreads, nThreads, |
69 |
0L, TimeUnit.MILLISECONDS, |
70 |
new LinkedBlockingQueue<Runnable>(), |
71 |
threadFactory); |
72 |
} |
73 |
|
74 |
/** |
75 |
* Creates an Executor that uses a single worker thread operating |
76 |
* off an unbounded queue. (Note however that if this single |
77 |
* thread terminates due to a failure during execution prior to |
78 |
* shutdown, a new one will take its place if needed to execute |
79 |
* subsequent tasks.) Tasks are guaranteed to execute |
80 |
* sequentially, and no more than one task will be active at any |
81 |
* given time. Unlike the otherwise equivalent |
82 |
* <tt>newFixedThreadPool(1)</tt> the returned executor is |
83 |
* guaranteed not to be reconfigurable to use additional threads. |
84 |
* |
85 |
* @return the newly created single-threaded Executor |
86 |
*/ |
87 |
public static ExecutorService newSingleThreadExecutor() { |
88 |
return new DelegatedExecutorService |
89 |
(new ThreadPoolExecutor(1, 1, |
90 |
0L, TimeUnit.MILLISECONDS, |
91 |
new LinkedBlockingQueue<Runnable>())); |
92 |
} |
93 |
|
94 |
/** |
95 |
* Creates an Executor that uses a single worker thread operating |
96 |
* off an unbounded queue, and uses the provided ThreadFactory to |
97 |
* create a new thread when needed. Unlike the otherwise |
98 |
* equivalent <tt>newFixedThreadPool(1, threadFactory)</tt> the returned executor |
99 |
* is guaranteed not to be reconfigurable to use additional |
100 |
* threads. |
101 |
* |
102 |
* @param threadFactory the factory to use when creating new |
103 |
* threads |
104 |
* |
105 |
* @return the newly created single-threaded Executor |
106 |
*/ |
107 |
public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory) { |
108 |
return new DelegatedExecutorService |
109 |
(new ThreadPoolExecutor(1, 1, |
110 |
0L, TimeUnit.MILLISECONDS, |
111 |
new LinkedBlockingQueue<Runnable>(), |
112 |
threadFactory)); |
113 |
} |
114 |
|
115 |
/** |
116 |
* Creates a thread pool that creates new threads as needed, but |
117 |
* will reuse previously constructed threads when they are |
118 |
* available. These pools will typically improve the performance |
119 |
* of programs that execute many short-lived asynchronous tasks. |
120 |
* Calls to <tt>execute</tt> will reuse previously constructed |
121 |
* threads if available. If no existing thread is available, a new |
122 |
* thread will be created and added to the pool. Threads that have |
123 |
* not been used for sixty seconds are terminated and removed from |
124 |
* the cache. Thus, a pool that remains idle for long enough will |
125 |
* not consume any resources. Note that pools with similar |
126 |
* properties but different details (for example, timeout parameters) |
127 |
* may be created using {@link ThreadPoolExecutor} constructors. |
128 |
* |
129 |
* @return the newly created thread pool |
130 |
*/ |
131 |
public static ExecutorService newCachedThreadPool() { |
132 |
return new ThreadPoolExecutor(0, Integer.MAX_VALUE, |
133 |
60L, TimeUnit.SECONDS, |
134 |
new SynchronousQueue<Runnable>()); |
135 |
} |
136 |
|
137 |
/** |
138 |
* Creates a thread pool that creates new threads as needed, but |
139 |
* will reuse previously constructed threads when they are |
140 |
* available, and uses the provided |
141 |
* ThreadFactory to create new threads when needed. |
142 |
* @param threadFactory the factory to use when creating new threads |
143 |
* @return the newly created thread pool |
144 |
*/ |
145 |
public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory) { |
146 |
return new ThreadPoolExecutor(0, Integer.MAX_VALUE, |
147 |
60L, TimeUnit.SECONDS, |
148 |
new SynchronousQueue<Runnable>(), |
149 |
threadFactory); |
150 |
} |
151 |
|
152 |
/** |
153 |
* Creates a single-threaded executor that can schedule commands |
154 |
* to run after a given delay, or to execute periodically. |
155 |
* (Note however that if this single |
156 |
* thread terminates due to a failure during execution prior to |
157 |
* shutdown, a new one will take its place if needed to execute |
158 |
* subsequent tasks.) Tasks are guaranteed to execute |
159 |
* sequentially, and no more than one task will be active at any |
160 |
* given time. Unlike the otherwise equivalent |
161 |
* <tt>newScheduledThreadPool(1)</tt> the returned executor is |
162 |
* guaranteed not to be reconfigurable to use additional threads. |
163 |
* @return the newly created scheduled executor |
164 |
*/ |
165 |
public static ScheduledExecutorService newSingleThreadScheduledExecutor() { |
166 |
return new DelegatedScheduledExecutorService |
167 |
(new ScheduledThreadPoolExecutor(1)); |
168 |
} |
169 |
|
170 |
/** |
171 |
* Creates a single-threaded executor that can schedule commands |
172 |
* to run after a given delay, or to execute periodically. (Note |
173 |
* however that if this single thread terminates due to a failure |
174 |
* during execution prior to shutdown, a new one will take its |
175 |
* place if needed to execute subsequent tasks.) Tasks are |
176 |
* guaranteed to execute sequentially, and no more than one task |
177 |
* will be active at any given time. Unlike the otherwise |
178 |
* equivalent <tt>newScheduledThreadPool(1, threadFactory)</tt> |
179 |
* the returned executor is guaranteed not to be reconfigurable to |
180 |
* use additional threads. |
181 |
* @param threadFactory the factory to use when creating new |
182 |
* threads |
183 |
* @return a newly created scheduled executor |
184 |
*/ |
185 |
public static ScheduledExecutorService newSingleThreadScheduledExecutor(ThreadFactory threadFactory) { |
186 |
return new DelegatedScheduledExecutorService |
187 |
(new ScheduledThreadPoolExecutor(1, threadFactory)); |
188 |
} |
189 |
|
190 |
/** |
191 |
* Creates a thread pool that can schedule commands to run after a |
192 |
* given delay, or to execute periodically. |
193 |
* @param corePoolSize the number of threads to keep in the pool, |
194 |
* even if they are idle. |
195 |
* @return a newly created scheduled thread pool |
196 |
*/ |
197 |
public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) { |
198 |
return new ScheduledThreadPoolExecutor(corePoolSize); |
199 |
} |
200 |
|
201 |
/** |
202 |
* Creates a thread pool that can schedule commands to run after a |
203 |
* given delay, or to execute periodically. |
204 |
* @param corePoolSize the number of threads to keep in the pool, |
205 |
* even if they are idle. |
206 |
* @param threadFactory the factory to use when the executor |
207 |
* creates a new thread. |
208 |
* @return a newly created scheduled thread pool |
209 |
*/ |
210 |
public static ScheduledExecutorService newScheduledThreadPool( |
211 |
int corePoolSize, ThreadFactory threadFactory) { |
212 |
return new ScheduledThreadPoolExecutor(corePoolSize, threadFactory); |
213 |
} |
214 |
|
215 |
|
216 |
/** |
217 |
* Returns an object that delegates all defined {@link |
218 |
* ExecutorService} methods to the given executor, but not any |
219 |
* other methods that might otherwise be accessible using |
220 |
* casts. This provides a way to safely "freeze" configuration and |
221 |
* disallow tuning of a given concrete implementation. |
222 |
* @param executor the underlying implementation |
223 |
* @return an <tt>ExecutorService</tt> instance |
224 |
* @throws NullPointerException if executor null |
225 |
*/ |
226 |
public static ExecutorService unconfigurableExecutorService(ExecutorService executor) { |
227 |
if (executor == null) |
228 |
throw new NullPointerException(); |
229 |
return new DelegatedExecutorService(executor); |
230 |
} |
231 |
|
232 |
/** |
233 |
* Returns an object that delegates all defined {@link |
234 |
* ScheduledExecutorService} methods to the given executor, but |
235 |
* not any other methods that might otherwise be accessible using |
236 |
* casts. This provides a way to safely "freeze" configuration and |
237 |
* disallow tuning of a given concrete implementation. |
238 |
* @param executor the underlying implementation |
239 |
* @return a <tt>ScheduledExecutorService</tt> instance |
240 |
* @throws NullPointerException if executor null |
241 |
*/ |
242 |
public static ScheduledExecutorService unconfigurableScheduledExecutorService(ScheduledExecutorService executor) { |
243 |
if (executor == null) |
244 |
throw new NullPointerException(); |
245 |
return new DelegatedScheduledExecutorService(executor); |
246 |
} |
247 |
|
248 |
/** |
249 |
* Returns a default thread factory used to create new threads. |
250 |
* This factory creates all new threads used by an Executor in the |
251 |
* same {@link ThreadGroup}. If there is a {@link |
252 |
* java.lang.SecurityManager}, it uses the group of {@link |
253 |
* System#getSecurityManager}, else the group of the thread |
254 |
* invoking this <tt>defaultThreadFactory</tt> method. Each new |
255 |
* thread is created as a non-daemon thread with priority |
256 |
* <tt>Thread.NORM_PRIORITY</tt>. New threads have names |
257 |
* accessible via {@link Thread#getName} of |
258 |
* <em>pool-N-thread-M</em>, where <em>N</em> is the sequence |
259 |
* number of this factory, and <em>M</em> is the sequence number |
260 |
* of the thread created by this factory. |
261 |
* @return a thread factory |
262 |
*/ |
263 |
public static ThreadFactory defaultThreadFactory() { |
264 |
return new DefaultThreadFactory(); |
265 |
} |
266 |
|
267 |
/** |
268 |
* Returns a thread factory used to create new threads that |
269 |
* have the same permissions as the current thread. |
270 |
* This factory creates threads with the same settings as {@link |
271 |
* Executors#defaultThreadFactory}, additionally setting the |
272 |
* AccessControlContext and contextClassLoader of new threads to |
273 |
* be the same as the thread invoking this |
274 |
* <tt>privilegedThreadFactory</tt> method. A new |
275 |
* <tt>privilegedThreadFactory</tt> can be created within an |
276 |
* {@link AccessController#doPrivileged} action setting the |
277 |
* current thread's access control context to create threads with |
278 |
* the selected permission settings holding within that action. |
279 |
* |
280 |
* <p> Note that while tasks running within such threads will have |
281 |
* the same access control and class loader settings as the |
282 |
* current thread, they need not have the same {@link |
283 |
* java.lang.ThreadLocal} or {@link |
284 |
* java.lang.InheritableThreadLocal} values. If necessary, |
285 |
* particular values of thread locals can be set or reset before |
286 |
* any task runs in {@link ThreadPoolExecutor} subclasses using |
287 |
* {@link ThreadPoolExecutor#beforeExecute}. Also, if it is |
288 |
* necessary to initialize worker threads to have the same |
289 |
* InheritableThreadLocal settings as some other designated |
290 |
* thread, you can create a custom ThreadFactory in which that |
291 |
* thread waits for and services requests to create others that |
292 |
* will inherit its values. |
293 |
* |
294 |
* @return a thread factory |
295 |
* @throws AccessControlException if the current access control |
296 |
* context does not have permission to both get and set context |
297 |
* class loader. |
298 |
*/ |
299 |
public static ThreadFactory privilegedThreadFactory() { |
300 |
return new PrivilegedThreadFactory(); |
301 |
} |
302 |
|
303 |
/** |
304 |
* Returns a {@link Callable} object that, when |
305 |
* called, runs the given task and returns the given result. This |
306 |
* can be useful when applying methods requiring a |
307 |
* <tt>Callable</tt> to an otherwise resultless action. |
308 |
* @param task the task to run |
309 |
* @param result the result to return |
310 |
* @throws NullPointerException if task null |
311 |
* @return a callable object |
312 |
*/ |
313 |
public static <T> Callable<T> callable(Runnable task, T result) { |
314 |
if (task == null) |
315 |
throw new NullPointerException(); |
316 |
return new RunnableAdapter<T>(task, result); |
317 |
} |
318 |
|
319 |
/** |
320 |
* Returns a {@link Callable} object that, when |
321 |
* called, runs the given task and returns <tt>null</tt>. |
322 |
* @param task the task to run |
323 |
* @return a callable object |
324 |
* @throws NullPointerException if task null |
325 |
*/ |
326 |
public static Callable<Object> callable(Runnable task) { |
327 |
if (task == null) |
328 |
throw new NullPointerException(); |
329 |
return new RunnableAdapter<Object>(task, null); |
330 |
} |
331 |
|
332 |
/** |
333 |
* Returns a {@link Callable} object that, when |
334 |
* called, runs the given privileged action and returns its result. |
335 |
* @param action the privileged action to run |
336 |
* @return a callable object |
337 |
* @throws NullPointerException if action null |
338 |
*/ |
339 |
public static Callable<Object> callable(PrivilegedAction action) { |
340 |
if (action == null) |
341 |
throw new NullPointerException(); |
342 |
return new PrivilegedActionAdapter(action); |
343 |
} |
344 |
|
345 |
/** |
346 |
* Returns a {@link Callable} object that, when |
347 |
* called, runs the given privileged exception action and returns |
348 |
* its result. |
349 |
* @param action the privileged exception action to run |
350 |
* @return a callable object |
351 |
* @throws NullPointerException if action null |
352 |
*/ |
353 |
public static Callable<Object> callable(PrivilegedExceptionAction action) { |
354 |
if (action == null) |
355 |
throw new NullPointerException(); |
356 |
return new PrivilegedExceptionActionAdapter(action); |
357 |
} |
358 |
|
359 |
/** |
360 |
* Returns a {@link Callable} object that will, when |
361 |
* called, execute the given <tt>callable</tt> under the current |
362 |
* access control context. This method should normally be |
363 |
* invoked within an {@link AccessController#doPrivileged} action |
364 |
* to create callables that will, if possible, execute under the |
365 |
* selected permission settings holding within that action; or if |
366 |
* not possible, throw an associated {@link |
367 |
* AccessControlException}. |
368 |
* @param callable the underlying task |
369 |
* @return a callable object |
370 |
* @throws NullPointerException if callable null |
371 |
* |
372 |
*/ |
373 |
public static <T> Callable<T> privilegedCallable(Callable<T> callable) { |
374 |
if (callable == null) |
375 |
throw new NullPointerException(); |
376 |
return new PrivilegedCallable(callable); |
377 |
} |
378 |
|
379 |
/** |
380 |
* Returns a {@link Callable} object that will, when |
381 |
* called, execute the given <tt>callable</tt> under the current |
382 |
* access control context, with the current context class loader |
383 |
* as the context class loader. This method should normally be |
384 |
* invoked within an {@link AccessController#doPrivileged} action |
385 |
* to create callables that will, if possible, execute under the |
386 |
* selected permission settings holding within that action; or if |
387 |
* not possible, throw an associated {@link |
388 |
* AccessControlException}. |
389 |
* @param callable the underlying task |
390 |
* |
391 |
* @return a callable object |
392 |
* @throws NullPointerException if callable null |
393 |
* @throws AccessControlException if the current access control |
394 |
* context does not have permission to both set and get context |
395 |
* class loader. |
396 |
*/ |
397 |
public static <T> Callable<T> privilegedCallableUsingCurrentClassLoader(Callable<T> callable) { |
398 |
if (callable == null) |
399 |
throw new NullPointerException(); |
400 |
return new PrivilegedCallableUsingCurrentClassLoader(callable); |
401 |
} |
402 |
|
403 |
// Non-public classes supporting the public methods |
404 |
|
405 |
/** |
406 |
* A callable that runs given task and returns given result |
407 |
*/ |
408 |
static final class RunnableAdapter<T> implements Callable<T> { |
409 |
final Runnable task; |
410 |
final T result; |
411 |
RunnableAdapter(Runnable task, T result) { |
412 |
this.task = task; |
413 |
this.result = result; |
414 |
} |
415 |
public T call() { |
416 |
task.run(); |
417 |
return result; |
418 |
} |
419 |
} |
420 |
|
421 |
/** |
422 |
* A callable that runs given privileged action and returns its result |
423 |
*/ |
424 |
static final class PrivilegedActionAdapter implements Callable<Object> { |
425 |
PrivilegedActionAdapter(PrivilegedAction action) { |
426 |
this.action = action; |
427 |
} |
428 |
public Object call () { |
429 |
return action.run(); |
430 |
} |
431 |
private final PrivilegedAction action; |
432 |
} |
433 |
|
434 |
/** |
435 |
* A callable that runs given privileged exception action and returns its result |
436 |
*/ |
437 |
static final class PrivilegedExceptionActionAdapter implements Callable<Object> { |
438 |
PrivilegedExceptionActionAdapter(PrivilegedExceptionAction action) { |
439 |
this.action = action; |
440 |
} |
441 |
public Object call () throws Exception { |
442 |
return action.run(); |
443 |
} |
444 |
private final PrivilegedExceptionAction action; |
445 |
} |
446 |
|
447 |
|
448 |
/** |
449 |
* A callable that runs under established access control settings |
450 |
*/ |
451 |
static final class PrivilegedCallable<T> implements Callable<T> { |
452 |
private final AccessControlContext acc; |
453 |
private final Callable<T> task; |
454 |
private T result; |
455 |
private Exception exception; |
456 |
PrivilegedCallable(Callable<T> task) { |
457 |
this.task = task; |
458 |
this.acc = AccessController.getContext(); |
459 |
} |
460 |
|
461 |
public T call() throws Exception { |
462 |
AccessController.doPrivileged(new PrivilegedAction() { |
463 |
public Object run() { |
464 |
try { |
465 |
result = task.call(); |
466 |
} catch(Exception ex) { |
467 |
exception = ex; |
468 |
} |
469 |
return null; |
470 |
} |
471 |
}, acc); |
472 |
if (exception != null) |
473 |
throw exception; |
474 |
else |
475 |
return result; |
476 |
} |
477 |
} |
478 |
|
479 |
/** |
480 |
* A callable that runs under established access control settings and |
481 |
* current ClassLoader |
482 |
*/ |
483 |
static final class PrivilegedCallableUsingCurrentClassLoader<T> implements Callable<T> { |
484 |
private final ClassLoader ccl; |
485 |
private final AccessControlContext acc; |
486 |
private final Callable<T> task; |
487 |
private T result; |
488 |
private Exception exception; |
489 |
PrivilegedCallableUsingCurrentClassLoader(Callable<T> task) { |
490 |
this.task = task; |
491 |
this.ccl = Thread.currentThread().getContextClassLoader(); |
492 |
this.acc = AccessController.getContext(); |
493 |
acc.checkPermission(new RuntimePermission("getContextClassLoader")); |
494 |
acc.checkPermission(new RuntimePermission("setContextClassLoader")); |
495 |
} |
496 |
|
497 |
public T call() throws Exception { |
498 |
AccessController.doPrivileged(new PrivilegedAction() { |
499 |
public Object run() { |
500 |
ClassLoader savedcl = null; |
501 |
Thread t = Thread.currentThread(); |
502 |
try { |
503 |
ClassLoader cl = t.getContextClassLoader(); |
504 |
if (ccl != cl) { |
505 |
t.setContextClassLoader(ccl); |
506 |
savedcl = cl; |
507 |
} |
508 |
result = task.call(); |
509 |
} catch(Exception ex) { |
510 |
exception = ex; |
511 |
} finally { |
512 |
if (savedcl != null) |
513 |
t.setContextClassLoader(savedcl); |
514 |
} |
515 |
return null; |
516 |
} |
517 |
}, acc); |
518 |
if (exception != null) |
519 |
throw exception; |
520 |
else |
521 |
return result; |
522 |
} |
523 |
} |
524 |
|
525 |
/** |
526 |
* The default thread factory |
527 |
*/ |
528 |
static class DefaultThreadFactory implements ThreadFactory { |
529 |
static final AtomicInteger poolNumber = new AtomicInteger(1); |
530 |
final ThreadGroup group; |
531 |
final AtomicInteger threadNumber = new AtomicInteger(1); |
532 |
final String namePrefix; |
533 |
|
534 |
DefaultThreadFactory() { |
535 |
SecurityManager s = System.getSecurityManager(); |
536 |
group = (s != null)? s.getThreadGroup() : |
537 |
Thread.currentThread().getThreadGroup(); |
538 |
namePrefix = "pool-" + |
539 |
poolNumber.getAndIncrement() + |
540 |
"-thread-"; |
541 |
} |
542 |
|
543 |
public Thread newThread(Runnable r) { |
544 |
Thread t = new Thread(group, r, |
545 |
namePrefix + threadNumber.getAndIncrement(), |
546 |
0); |
547 |
if (t.isDaemon()) |
548 |
t.setDaemon(false); |
549 |
if (t.getPriority() != Thread.NORM_PRIORITY) |
550 |
t.setPriority(Thread.NORM_PRIORITY); |
551 |
return t; |
552 |
} |
553 |
} |
554 |
|
555 |
/** |
556 |
* Thread factory capturing access control and class loader |
557 |
*/ |
558 |
static class PrivilegedThreadFactory extends DefaultThreadFactory { |
559 |
private final ClassLoader ccl; |
560 |
private final AccessControlContext acc; |
561 |
|
562 |
PrivilegedThreadFactory() { |
563 |
super(); |
564 |
this.ccl = Thread.currentThread().getContextClassLoader(); |
565 |
this.acc = AccessController.getContext(); |
566 |
acc.checkPermission(new RuntimePermission("setContextClassLoader")); |
567 |
} |
568 |
|
569 |
public Thread newThread(final Runnable r) { |
570 |
return super.newThread(new Runnable() { |
571 |
public void run() { |
572 |
AccessController.doPrivileged(new PrivilegedAction() { |
573 |
public Object run() { |
574 |
Thread.currentThread().setContextClassLoader(ccl); |
575 |
r.run(); |
576 |
return null; |
577 |
} |
578 |
}, acc); |
579 |
} |
580 |
}); |
581 |
} |
582 |
|
583 |
} |
584 |
|
585 |
/** |
586 |
* A wrapper class that exposes only the ExecutorService methods |
587 |
* of an implementation. |
588 |
*/ |
589 |
static class DelegatedExecutorService extends AbstractExecutorService { |
590 |
private final ExecutorService e; |
591 |
DelegatedExecutorService(ExecutorService executor) { e = executor; } |
592 |
public void execute(Runnable command) { e.execute(command); } |
593 |
public void shutdown() { e.shutdown(); } |
594 |
public List<Runnable> shutdownNow() { return e.shutdownNow(); } |
595 |
public boolean isShutdown() { return e.isShutdown(); } |
596 |
public boolean isTerminated() { return e.isTerminated(); } |
597 |
public boolean awaitTermination(long timeout, TimeUnit unit) |
598 |
throws InterruptedException { |
599 |
return e.awaitTermination(timeout, unit); |
600 |
} |
601 |
public Future<?> submit(Runnable task) { |
602 |
return e.submit(task); |
603 |
} |
604 |
public <T> Future<T> submit(Callable<T> task) { |
605 |
return e.submit(task); |
606 |
} |
607 |
public <T> Future<T> submit(Runnable task, T result) { |
608 |
return e.submit(task, result); |
609 |
} |
610 |
public <T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks) |
611 |
throws InterruptedException { |
612 |
return e.invokeAll(tasks); |
613 |
} |
614 |
public <T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks, |
615 |
long timeout, TimeUnit unit) |
616 |
throws InterruptedException { |
617 |
return e.invokeAll(tasks, timeout, unit); |
618 |
} |
619 |
public <T> T invokeAny(Collection<Callable<T>> tasks) |
620 |
throws InterruptedException, ExecutionException { |
621 |
return e.invokeAny(tasks); |
622 |
} |
623 |
public <T> T invokeAny(Collection<Callable<T>> tasks, |
624 |
long timeout, TimeUnit unit) |
625 |
throws InterruptedException, ExecutionException, TimeoutException { |
626 |
return e.invokeAny(tasks, timeout, unit); |
627 |
} |
628 |
} |
629 |
|
630 |
/** |
631 |
* A wrapper class that exposes only the ExecutorService and |
632 |
* ScheduleExecutor methods of a ScheduledExecutorService implementation. |
633 |
*/ |
634 |
static class DelegatedScheduledExecutorService |
635 |
extends DelegatedExecutorService |
636 |
implements ScheduledExecutorService { |
637 |
private final ScheduledExecutorService e; |
638 |
DelegatedScheduledExecutorService(ScheduledExecutorService executor) { |
639 |
super(executor); |
640 |
e = executor; |
641 |
} |
642 |
public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) { |
643 |
return e.schedule(command, delay, unit); |
644 |
} |
645 |
public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) { |
646 |
return e.schedule(callable, delay, unit); |
647 |
} |
648 |
public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) { |
649 |
return e.scheduleAtFixedRate(command, initialDelay, period, unit); |
650 |
} |
651 |
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) { |
652 |
return e.scheduleWithFixedDelay(command, initialDelay, delay, unit); |
653 |
} |
654 |
} |
655 |
|
656 |
|
657 |
/** Cannot instantiate. */ |
658 |
private Executors() {} |
659 |
} |