5 |
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*/ |
6 |
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package jsr166y; |
8 |
< |
import java.util.*; |
8 |
> |
|
9 |
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import java.util.concurrent.*; |
10 |
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import java.util.concurrent.locks.*; |
11 |
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import java.util.concurrent.atomic.*; |
12 |
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import sun.misc.Unsafe; |
13 |
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import java.lang.reflect.*; |
10 |
> |
|
11 |
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import java.util.ArrayList; |
12 |
> |
import java.util.Arrays; |
13 |
> |
import java.util.Collection; |
14 |
> |
import java.util.Collections; |
15 |
> |
import java.util.List; |
16 |
> |
import java.util.concurrent.locks.Condition; |
17 |
> |
import java.util.concurrent.locks.LockSupport; |
18 |
> |
import java.util.concurrent.locks.ReentrantLock; |
19 |
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import java.util.concurrent.atomic.AtomicInteger; |
20 |
> |
import java.util.concurrent.atomic.AtomicLong; |
21 |
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|
22 |
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/** |
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* An {@link ExecutorService} for running {@link ForkJoinTask}s. A |
24 |
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* ForkJoinPool provides the entry point for submissions from |
25 |
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* non-ForkJoinTasks, as well as management and monitoring operations. |
26 |
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* Normally a single ForkJoinPool is used for a large number of |
20 |
< |
* submitted tasks. Otherwise, use would not usually outweigh the |
21 |
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* construction and bookkeeping overhead of creating a large set of |
22 |
< |
* threads. |
23 |
> |
* An {@link ExecutorService} for running {@link ForkJoinTask}s. |
24 |
> |
* A {@code ForkJoinPool} provides the entry point for submissions |
25 |
> |
* from non-{@code ForkJoinTask}s, as well as management and |
26 |
> |
* monitoring operations. |
27 |
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* |
28 |
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* <p>ForkJoinPools differ from other kinds of Executors mainly in |
29 |
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* that they provide <em>work-stealing</em>: all threads in the pool |
30 |
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* attempt to find and execute subtasks created by other active tasks |
31 |
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* (eventually blocking if none exist). This makes them efficient when |
32 |
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* most tasks spawn other subtasks (as do most ForkJoinTasks), as well |
33 |
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* as the mixed execution of some plain Runnable- or Callable- based |
34 |
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* activities along with ForkJoinTasks. When setting |
35 |
< |
* {@code setAsyncMode}, a ForkJoinPools may also be appropriate for |
36 |
< |
* use with fine-grained tasks that are never joined. Otherwise, other |
37 |
< |
* ExecutorService implementations are typically more appropriate |
38 |
< |
* choices. |
28 |
> |
* <p>A {@code ForkJoinPool} differs from other kinds of {@link |
29 |
> |
* ExecutorService} mainly by virtue of employing |
30 |
> |
* <em>work-stealing</em>: all threads in the pool attempt to find and |
31 |
> |
* execute subtasks created by other active tasks (eventually blocking |
32 |
> |
* waiting for work if none exist). This enables efficient processing |
33 |
> |
* when most tasks spawn other subtasks (as do most {@code |
34 |
> |
* ForkJoinTask}s). A {@code ForkJoinPool} may also be used for mixed |
35 |
> |
* execution of some plain {@code Runnable}- or {@code Callable}- |
36 |
> |
* based activities along with {@code ForkJoinTask}s. When setting |
37 |
> |
* {@linkplain #setAsyncMode async mode}, a {@code ForkJoinPool} may |
38 |
> |
* also be appropriate for use with fine-grained tasks of any form |
39 |
> |
* that are never joined. Otherwise, other {@code ExecutorService} |
40 |
> |
* implementations are typically more appropriate choices. |
41 |
|
* |
42 |
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* <p>A ForkJoinPool may be constructed with a given parallelism level |
43 |
< |
* (target pool size), which it attempts to maintain by dynamically |
44 |
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* adding, suspending, or resuming threads, even if some tasks are |
45 |
< |
* waiting to join others. However, no such adjustments are performed |
46 |
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* in the face of blocked IO or other unmanaged synchronization. The |
47 |
< |
* nested {@code ManagedBlocker} interface enables extension of |
48 |
< |
* the kinds of synchronization accommodated. The target parallelism |
49 |
< |
* level may also be changed dynamically ({@code setParallelism}) |
50 |
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* and thread construction can be limited using methods |
51 |
< |
* {@code setMaximumPoolSize} and/or |
52 |
< |
* {@code setMaintainsParallelism}. |
42 |
> |
* <p>A {@code ForkJoinPool} is constructed with a given target |
43 |
> |
* parallelism level; by default, equal to the number of available |
44 |
> |
* processors. Unless configured otherwise via {@link |
45 |
> |
* #setMaintainsParallelism}, the pool attempts to maintain this |
46 |
> |
* number of active (or available) threads by dynamically adding, |
47 |
> |
* suspending, or resuming internal worker threads, even if some tasks |
48 |
> |
* are stalled waiting to join others. However, no such adjustments |
49 |
> |
* are performed in the face of blocked IO or other unmanaged |
50 |
> |
* synchronization. The nested {@link ManagedBlocker} interface |
51 |
> |
* enables extension of the kinds of synchronization accommodated. |
52 |
> |
* The target parallelism level may also be changed dynamically |
53 |
> |
* ({@link #setParallelism}). The total number of threads may be |
54 |
> |
* limited using method {@link #setMaximumPoolSize}, in which case it |
55 |
> |
* may become possible for the activities of a pool to stall due to |
56 |
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* the lack of available threads to process new tasks. |
57 |
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* |
58 |
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* <p>In addition to execution and lifecycle control methods, this |
59 |
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* class provides status check methods (for example |
60 |
< |
* {@code getStealCount}) that are intended to aid in developing, |
60 |
> |
* {@link #getStealCount}) that are intended to aid in developing, |
61 |
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* tuning, and monitoring fork/join applications. Also, method |
62 |
< |
* {@code toString} returns indications of pool state in a |
62 |
> |
* {@link #toString} returns indications of pool state in a |
63 |
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* convenient form for informal monitoring. |
64 |
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* |
65 |
+ |
* <p><b>Sample Usage.</b> Normally a single {@code ForkJoinPool} is |
66 |
+ |
* used for all parallel task execution in a program or subsystem. |
67 |
+ |
* Otherwise, use would not usually outweigh the construction and |
68 |
+ |
* bookkeeping overhead of creating a large set of threads. For |
69 |
+ |
* example, a common pool could be used for the {@code SortTasks} |
70 |
+ |
* illustrated in {@link RecursiveAction}. Because {@code |
71 |
+ |
* ForkJoinPool} uses threads in {@linkplain java.lang.Thread#isDaemon |
72 |
+ |
* daemon} mode, there is typically no need to explicitly {@link |
73 |
+ |
* #shutdown} such a pool upon program exit. |
74 |
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* |
75 |
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* <pre> |
76 |
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* static final ForkJoinPool mainPool = new ForkJoinPool(); |
77 |
+ |
* ... |
78 |
+ |
* public void sort(long[] array) { |
79 |
+ |
* mainPool.invoke(new SortTask(array, 0, array.length)); |
80 |
+ |
* } |
81 |
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* </pre> |
82 |
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* |
83 |
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* <p><b>Implementation notes</b>: This implementation restricts the |
84 |
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* maximum number of running threads to 32767. Attempts to create |
85 |
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* pools with greater than the maximum result in |
86 |
< |
* IllegalArgumentExceptions. |
85 |
> |
* pools with greater than the maximum number result in |
86 |
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* {@code IllegalArgumentException}. |
87 |
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* |
88 |
> |
* <p>This implementation rejects submitted tasks (that is, by throwing |
89 |
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* {@link RejectedExecutionException}) only when the pool is shut down. |
90 |
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* |
91 |
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* @since 1.7 |
92 |
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* @author Doug Lea |
105 |
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private static final int MAX_THREADS = 0x7FFF; |
106 |
|
|
107 |
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/** |
108 |
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* Factory for creating new ForkJoinWorkerThreads. A |
109 |
< |
* ForkJoinWorkerThreadFactory must be defined and used for |
110 |
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* ForkJoinWorkerThread subclasses that extend base functionality |
111 |
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* or initialize threads with different contexts. |
108 |
> |
* Factory for creating new {@link ForkJoinWorkerThread}s. |
109 |
> |
* A {@code ForkJoinWorkerThreadFactory} must be defined and used |
110 |
> |
* for {@code ForkJoinWorkerThread} subclasses that extend base |
111 |
> |
* functionality or initialize threads with different contexts. |
112 |
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*/ |
113 |
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public static interface ForkJoinWorkerThreadFactory { |
114 |
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/** |
115 |
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* Returns a new worker thread operating in the given pool. |
116 |
|
* |
117 |
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* @param pool the pool this thread works in |
118 |
< |
* @throws NullPointerException if pool is null |
118 |
> |
* @throws NullPointerException if the pool is null |
119 |
|
*/ |
120 |
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public ForkJoinWorkerThread newThread(ForkJoinPool pool); |
121 |
|
} |
335 |
|
} |
336 |
|
|
337 |
|
/** |
338 |
< |
* Returns true if argument represents zero active count and |
339 |
< |
* nonzero runstate, which is the triggering condition for |
338 |
> |
* Returns {@code true} if argument represents zero active count |
339 |
> |
* and nonzero runstate, which is the triggering condition for |
340 |
|
* terminating on shutdown. |
341 |
|
*/ |
342 |
|
private static boolean canTerminateOnShutdown(int c) { |
366 |
|
// Constructors |
367 |
|
|
368 |
|
/** |
369 |
< |
* Creates a ForkJoinPool with a pool size equal to the number of |
370 |
< |
* processors available on the system, using the default |
371 |
< |
* ForkJoinWorkerThreadFactory. |
369 |
> |
* Creates a {@code ForkJoinPool} with parallelism equal to {@link |
370 |
> |
* java.lang.Runtime#availableProcessors}, and using the {@linkplain |
371 |
> |
* #defaultForkJoinWorkerThreadFactory default thread factory}. |
372 |
|
* |
373 |
|
* @throws SecurityException if a security manager exists and |
374 |
|
* the caller is not permitted to modify threads |
381 |
|
} |
382 |
|
|
383 |
|
/** |
384 |
< |
* Creates a ForkJoinPool with the indicated parallelism level |
385 |
< |
* threads and using the default ForkJoinWorkerThreadFactory. |
384 |
> |
* Creates a {@code ForkJoinPool} with the indicated parallelism |
385 |
> |
* level and using the {@linkplain |
386 |
> |
* #defaultForkJoinWorkerThreadFactory default thread factory}. |
387 |
|
* |
388 |
< |
* @param parallelism the number of worker threads |
388 |
> |
* @param parallelism the parallelism level |
389 |
|
* @throws IllegalArgumentException if parallelism less than or |
390 |
< |
* equal to zero |
390 |
> |
* equal to zero, or greater than implementation limit |
391 |
|
* @throws SecurityException if a security manager exists and |
392 |
|
* the caller is not permitted to modify threads |
393 |
|
* because it does not hold {@link |
398 |
|
} |
399 |
|
|
400 |
|
/** |
401 |
< |
* Creates a ForkJoinPool with parallelism equal to the number of |
402 |
< |
* processors available on the system and using the given |
403 |
< |
* ForkJoinWorkerThreadFactory. |
401 |
> |
* Creates a {@code ForkJoinPool} with parallelism equal to {@link |
402 |
> |
* java.lang.Runtime#availableProcessors}, and using the given |
403 |
> |
* thread factory. |
404 |
|
* |
405 |
|
* @param factory the factory for creating new threads |
406 |
< |
* @throws NullPointerException if factory is null |
406 |
> |
* @throws NullPointerException if the factory is null |
407 |
|
* @throws SecurityException if a security manager exists and |
408 |
|
* the caller is not permitted to modify threads |
409 |
|
* because it does not hold {@link |
414 |
|
} |
415 |
|
|
416 |
|
/** |
417 |
< |
* Creates a ForkJoinPool with the given parallelism and factory. |
417 |
> |
* Creates a {@code ForkJoinPool} with the given parallelism and |
418 |
> |
* thread factory. |
419 |
|
* |
420 |
< |
* @param parallelism the targeted number of worker threads |
420 |
> |
* @param parallelism the parallelism level |
421 |
|
* @param factory the factory for creating new threads |
422 |
|
* @throws IllegalArgumentException if parallelism less than or |
423 |
< |
* equal to zero, or greater than implementation limit |
424 |
< |
* @throws NullPointerException if factory is null |
423 |
> |
* equal to zero, or greater than implementation limit |
424 |
> |
* @throws NullPointerException if the factory is null |
425 |
|
* @throws SecurityException if a security manager exists and |
426 |
|
* the caller is not permitted to modify threads |
427 |
|
* because it does not hold {@link |
449 |
|
* Creates a new worker thread using factory. |
450 |
|
* |
451 |
|
* @param index the index to assign worker |
452 |
< |
* @return new worker, or null of factory failed |
452 |
> |
* @return new worker, or null if factory failed |
453 |
|
*/ |
454 |
|
private ForkJoinWorkerThread createWorker(int index) { |
455 |
|
Thread.UncaughtExceptionHandler h = ueh; |
470 |
|
* Currently requires size to be a power of two. |
471 |
|
*/ |
472 |
|
private static int arraySizeFor(int poolSize) { |
473 |
< |
return (poolSize <= 1) ? 1 : |
474 |
< |
(1 << (32 - Integer.numberOfLeadingZeros(poolSize-1))); |
473 |
> |
if (poolSize <= 1) |
474 |
> |
return 1; |
475 |
> |
// See Hackers Delight, sec 3.2 |
476 |
> |
int c = poolSize >= MAX_THREADS ? MAX_THREADS : (poolSize - 1); |
477 |
> |
c |= c >>> 1; |
478 |
> |
c |= c >>> 2; |
479 |
> |
c |= c >>> 4; |
480 |
> |
c |= c >>> 8; |
481 |
> |
c |= c >>> 16; |
482 |
> |
return c + 1; |
483 |
|
} |
484 |
|
|
485 |
|
/** |
582 |
|
* Common code for execute, invoke and submit |
583 |
|
*/ |
584 |
|
private <T> void doSubmit(ForkJoinTask<T> task) { |
585 |
+ |
if (task == null) |
586 |
+ |
throw new NullPointerException(); |
587 |
|
if (isShutdown()) |
588 |
|
throw new RejectedExecutionException(); |
589 |
|
if (workers == null) |
597 |
|
* |
598 |
|
* @param task the task |
599 |
|
* @return the task's result |
600 |
< |
* @throws NullPointerException if task is null |
601 |
< |
* @throws RejectedExecutionException if pool is shut down |
600 |
> |
* @throws NullPointerException if the task is null |
601 |
> |
* @throws RejectedExecutionException if the task cannot be |
602 |
> |
* scheduled for execution |
603 |
|
*/ |
604 |
|
public <T> T invoke(ForkJoinTask<T> task) { |
605 |
|
doSubmit(task); |
610 |
|
* Arranges for (asynchronous) execution of the given task. |
611 |
|
* |
612 |
|
* @param task the task |
613 |
< |
* @throws NullPointerException if task is null |
614 |
< |
* @throws RejectedExecutionException if pool is shut down |
613 |
> |
* @throws NullPointerException if the task is null |
614 |
> |
* @throws RejectedExecutionException if the task cannot be |
615 |
> |
* scheduled for execution |
616 |
|
*/ |
617 |
< |
public <T> void execute(ForkJoinTask<T> task) { |
617 |
> |
public void execute(ForkJoinTask<?> task) { |
618 |
|
doSubmit(task); |
619 |
|
} |
620 |
|
|
621 |
|
// AbstractExecutorService methods |
622 |
|
|
623 |
+ |
/** |
624 |
+ |
* @throws NullPointerException if the task is null |
625 |
+ |
* @throws RejectedExecutionException if the task cannot be |
626 |
+ |
* scheduled for execution |
627 |
+ |
*/ |
628 |
|
public void execute(Runnable task) { |
629 |
< |
doSubmit(new AdaptedRunnable<Void>(task, null)); |
629 |
> |
ForkJoinTask<?> job; |
630 |
> |
if (task instanceof ForkJoinTask<?>) // avoid re-wrap |
631 |
> |
job = (ForkJoinTask<?>) task; |
632 |
> |
else |
633 |
> |
job = ForkJoinTask.adapt(task, null); |
634 |
> |
doSubmit(job); |
635 |
|
} |
636 |
|
|
637 |
+ |
/** |
638 |
+ |
* @throws NullPointerException if the task is null |
639 |
+ |
* @throws RejectedExecutionException if the task cannot be |
640 |
+ |
* scheduled for execution |
641 |
+ |
*/ |
642 |
|
public <T> ForkJoinTask<T> submit(Callable<T> task) { |
643 |
< |
ForkJoinTask<T> job = new AdaptedCallable<T>(task); |
643 |
> |
ForkJoinTask<T> job = ForkJoinTask.adapt(task); |
644 |
|
doSubmit(job); |
645 |
|
return job; |
646 |
|
} |
647 |
|
|
648 |
+ |
/** |
649 |
+ |
* @throws NullPointerException if the task is null |
650 |
+ |
* @throws RejectedExecutionException if the task cannot be |
651 |
+ |
* scheduled for execution |
652 |
+ |
*/ |
653 |
|
public <T> ForkJoinTask<T> submit(Runnable task, T result) { |
654 |
< |
ForkJoinTask<T> job = new AdaptedRunnable<T>(task, result); |
654 |
> |
ForkJoinTask<T> job = ForkJoinTask.adapt(task, result); |
655 |
|
doSubmit(job); |
656 |
|
return job; |
657 |
|
} |
658 |
|
|
659 |
+ |
/** |
660 |
+ |
* @throws NullPointerException if the task is null |
661 |
+ |
* @throws RejectedExecutionException if the task cannot be |
662 |
+ |
* scheduled for execution |
663 |
+ |
*/ |
664 |
|
public ForkJoinTask<?> submit(Runnable task) { |
665 |
< |
ForkJoinTask<Void> job = new AdaptedRunnable<Void>(task, null); |
665 |
> |
ForkJoinTask<?> job; |
666 |
> |
if (task instanceof ForkJoinTask<?>) // avoid re-wrap |
667 |
> |
job = (ForkJoinTask<?>) task; |
668 |
> |
else |
669 |
> |
job = ForkJoinTask.adapt(task, null); |
670 |
|
doSubmit(job); |
671 |
|
return job; |
672 |
|
} |
673 |
|
|
674 |
|
/** |
675 |
< |
* Adaptor for Runnables. This implements RunnableFuture |
676 |
< |
* to be compliant with AbstractExecutorService constraints. |
675 |
> |
* Submits a ForkJoinTask for execution. |
676 |
> |
* |
677 |
> |
* @param task the task to submit |
678 |
> |
* @return the task |
679 |
> |
* @throws NullPointerException if the task is null |
680 |
> |
* @throws RejectedExecutionException if the task cannot be |
681 |
> |
* scheduled for execution |
682 |
|
*/ |
683 |
< |
static final class AdaptedRunnable<T> extends ForkJoinTask<T> |
684 |
< |
implements RunnableFuture<T> { |
685 |
< |
final Runnable runnable; |
607 |
< |
final T resultOnCompletion; |
608 |
< |
T result; |
609 |
< |
AdaptedRunnable(Runnable runnable, T result) { |
610 |
< |
if (runnable == null) throw new NullPointerException(); |
611 |
< |
this.runnable = runnable; |
612 |
< |
this.resultOnCompletion = result; |
613 |
< |
} |
614 |
< |
public T getRawResult() { return result; } |
615 |
< |
public void setRawResult(T v) { result = v; } |
616 |
< |
public boolean exec() { |
617 |
< |
runnable.run(); |
618 |
< |
result = resultOnCompletion; |
619 |
< |
return true; |
620 |
< |
} |
621 |
< |
public void run() { invoke(); } |
622 |
< |
private static final long serialVersionUID = 5232453952276885070L; |
683 |
> |
public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) { |
684 |
> |
doSubmit(task); |
685 |
> |
return task; |
686 |
|
} |
687 |
|
|
688 |
+ |
|
689 |
|
/** |
690 |
< |
* Adaptor for Callables |
690 |
> |
* @throws NullPointerException {@inheritDoc} |
691 |
> |
* @throws RejectedExecutionException {@inheritDoc} |
692 |
|
*/ |
628 |
– |
static final class AdaptedCallable<T> extends ForkJoinTask<T> |
629 |
– |
implements RunnableFuture<T> { |
630 |
– |
final Callable<T> callable; |
631 |
– |
T result; |
632 |
– |
AdaptedCallable(Callable<T> callable) { |
633 |
– |
if (callable == null) throw new NullPointerException(); |
634 |
– |
this.callable = callable; |
635 |
– |
} |
636 |
– |
public T getRawResult() { return result; } |
637 |
– |
public void setRawResult(T v) { result = v; } |
638 |
– |
public boolean exec() { |
639 |
– |
try { |
640 |
– |
result = callable.call(); |
641 |
– |
return true; |
642 |
– |
} catch (Error err) { |
643 |
– |
throw err; |
644 |
– |
} catch (RuntimeException rex) { |
645 |
– |
throw rex; |
646 |
– |
} catch (Exception ex) { |
647 |
– |
throw new RuntimeException(ex); |
648 |
– |
} |
649 |
– |
} |
650 |
– |
public void run() { invoke(); } |
651 |
– |
private static final long serialVersionUID = 2838392045355241008L; |
652 |
– |
} |
653 |
– |
|
693 |
|
public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) { |
694 |
|
ArrayList<ForkJoinTask<T>> forkJoinTasks = |
695 |
|
new ArrayList<ForkJoinTask<T>>(tasks.size()); |
696 |
|
for (Callable<T> task : tasks) |
697 |
< |
forkJoinTasks.add(new AdaptedCallable<T>(task)); |
697 |
> |
forkJoinTasks.add(ForkJoinTask.adapt(task)); |
698 |
|
invoke(new InvokeAll<T>(forkJoinTasks)); |
699 |
|
|
700 |
|
@SuppressWarnings({"unchecked", "rawtypes"}) |
727 |
|
* Returns the handler for internal worker threads that terminate |
728 |
|
* due to unrecoverable errors encountered while executing tasks. |
729 |
|
* |
730 |
< |
* @return the handler, or null if none |
730 |
> |
* @return the handler, or {@code null} if none |
731 |
|
*/ |
732 |
|
public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() { |
733 |
|
Thread.UncaughtExceptionHandler h; |
748 |
|
* as handler. |
749 |
|
* |
750 |
|
* @param h the new handler |
751 |
< |
* @return the old handler, or null if none |
751 |
> |
* @return the old handler, or {@code null} if none |
752 |
|
* @throws SecurityException if a security manager exists and |
753 |
|
* the caller is not permitted to modify threads |
754 |
|
* because it does not hold {@link |
796 |
|
final ReentrantLock lock = this.workerLock; |
797 |
|
lock.lock(); |
798 |
|
try { |
799 |
< |
if (!isTerminating()) { |
799 |
> |
if (isProcessingTasks()) { |
800 |
|
int p = this.parallelism; |
801 |
|
this.parallelism = parallelism; |
802 |
|
if (parallelism > p) |
811 |
|
} |
812 |
|
|
813 |
|
/** |
814 |
< |
* Returns the targeted number of worker threads in this pool. |
814 |
> |
* Returns the targeted parallelism level of this pool. |
815 |
|
* |
816 |
< |
* @return the targeted number of worker threads in this pool |
816 |
> |
* @return the targeted parallelism level of this pool |
817 |
|
*/ |
818 |
|
public int getParallelism() { |
819 |
|
return parallelism; |
822 |
|
/** |
823 |
|
* Returns the number of worker threads that have started but not |
824 |
|
* yet terminated. This result returned by this method may differ |
825 |
< |
* from {@code getParallelism} when threads are created to |
825 |
> |
* from {@link #getParallelism} when threads are created to |
826 |
|
* maintain parallelism when others are cooperatively blocked. |
827 |
|
* |
828 |
|
* @return the number of worker threads |
833 |
|
|
834 |
|
/** |
835 |
|
* Returns the maximum number of threads allowed to exist in the |
836 |
< |
* pool, even if there are insufficient unblocked running threads. |
836 |
> |
* pool. Unless set using {@link #setMaximumPoolSize}, the |
837 |
> |
* maximum is an implementation-defined value designed only to |
838 |
> |
* prevent runaway growth. |
839 |
|
* |
840 |
|
* @return the maximum |
841 |
|
*/ |
845 |
|
|
846 |
|
/** |
847 |
|
* Sets the maximum number of threads allowed to exist in the |
848 |
< |
* pool, even if there are insufficient unblocked running threads. |
849 |
< |
* Setting this value has no effect on current pool size. It |
850 |
< |
* controls construction of new threads. |
848 |
> |
* pool. The given value should normally be greater than or equal |
849 |
> |
* to the {@link #getParallelism parallelism} level. Setting this |
850 |
> |
* value has no effect on current pool size. It controls |
851 |
> |
* construction of new threads. |
852 |
|
* |
853 |
< |
* @throws IllegalArgumentException if negative or greater then |
853 |
> |
* @throws IllegalArgumentException if negative or greater than |
854 |
|
* internal implementation limit |
855 |
|
*/ |
856 |
|
public void setMaximumPoolSize(int newMax) { |
861 |
|
|
862 |
|
|
863 |
|
/** |
864 |
< |
* Returns true if this pool dynamically maintains its target |
865 |
< |
* parallelism level. If false, new threads are added only to |
866 |
< |
* avoid possible starvation. |
825 |
< |
* This setting is by default true. |
864 |
> |
* Returns {@code true} if this pool dynamically maintains its |
865 |
> |
* target parallelism level. If false, new threads are added only |
866 |
> |
* to avoid possible starvation. This setting is by default true. |
867 |
|
* |
868 |
< |
* @return true if maintains parallelism |
868 |
> |
* @return {@code true} if maintains parallelism |
869 |
|
*/ |
870 |
|
public boolean getMaintainsParallelism() { |
871 |
|
return maintainsParallelism; |
876 |
|
* parallelism level. If false, new threads are added only to |
877 |
|
* avoid possible starvation. |
878 |
|
* |
879 |
< |
* @param enable true to maintains parallelism |
879 |
> |
* @param enable {@code true} to maintain parallelism |
880 |
|
*/ |
881 |
|
public void setMaintainsParallelism(boolean enable) { |
882 |
|
maintainsParallelism = enable; |
887 |
|
* tasks that are never joined. This mode may be more appropriate |
888 |
|
* than default locally stack-based mode in applications in which |
889 |
|
* worker threads only process asynchronous tasks. This method is |
890 |
< |
* designed to be invoked only when pool is quiescent, and |
890 |
> |
* designed to be invoked only when the pool is quiescent, and |
891 |
|
* typically only before any tasks are submitted. The effects of |
892 |
|
* invocations at other times may be unpredictable. |
893 |
|
* |
894 |
< |
* @param async if true, use locally FIFO scheduling |
894 |
> |
* @param async if {@code true}, use locally FIFO scheduling |
895 |
|
* @return the previous mode |
896 |
+ |
* @see #getAsyncMode |
897 |
|
*/ |
898 |
|
public boolean setAsyncMode(boolean async) { |
899 |
|
boolean oldMode = locallyFifo; |
910 |
|
} |
911 |
|
|
912 |
|
/** |
913 |
< |
* Returns true if this pool uses local first-in-first-out |
913 |
> |
* Returns {@code true} if this pool uses local first-in-first-out |
914 |
|
* scheduling mode for forked tasks that are never joined. |
915 |
|
* |
916 |
< |
* @return true if this pool uses async mode |
916 |
> |
* @return {@code true} if this pool uses async mode |
917 |
> |
* @see #setAsyncMode |
918 |
|
*/ |
919 |
|
public boolean getAsyncMode() { |
920 |
|
return locallyFifo; |
955 |
|
} |
956 |
|
|
957 |
|
/** |
958 |
< |
* Returns true if all worker threads are currently idle. An idle |
959 |
< |
* worker is one that cannot obtain a task to execute because none |
960 |
< |
* are available to steal from other threads, and there are no |
961 |
< |
* pending submissions to the pool. This method is conservative; |
962 |
< |
* it might not return true immediately upon idleness of all |
963 |
< |
* threads, but will eventually become true if threads remain |
964 |
< |
* inactive. |
958 |
> |
* Returns {@code true} if all worker threads are currently idle. |
959 |
> |
* An idle worker is one that cannot obtain a task to execute |
960 |
> |
* because none are available to steal from other threads, and |
961 |
> |
* there are no pending submissions to the pool. This method is |
962 |
> |
* conservative; it might not return {@code true} immediately upon |
963 |
> |
* idleness of all threads, but will eventually become true if |
964 |
> |
* threads remain inactive. |
965 |
|
* |
966 |
< |
* @return true if all threads are currently idle |
966 |
> |
* @return {@code true} if all threads are currently idle |
967 |
|
*/ |
968 |
|
public boolean isQuiescent() { |
969 |
|
return activeCountOf(runControl) == 0; |
1018 |
|
} |
1019 |
|
|
1020 |
|
/** |
1021 |
< |
* Returns an estimate of the number tasks submitted to this pool |
1022 |
< |
* that have not yet begun executing. This method takes time |
1021 |
> |
* Returns an estimate of the number of tasks submitted to this |
1022 |
> |
* pool that have not yet begun executing. This method takes time |
1023 |
|
* proportional to the number of submissions. |
1024 |
|
* |
1025 |
|
* @return the number of queued submissions |
1029 |
|
} |
1030 |
|
|
1031 |
|
/** |
1032 |
< |
* Returns true if there are any tasks submitted to this pool |
1033 |
< |
* that have not yet begun executing. |
1032 |
> |
* Returns {@code true} if there are any tasks submitted to this |
1033 |
> |
* pool that have not yet begun executing. |
1034 |
|
* |
1035 |
|
* @return {@code true} if there are any queued submissions |
1036 |
|
*/ |
1043 |
|
* available. This method may be useful in extensions to this |
1044 |
|
* class that re-assign work in systems with multiple pools. |
1045 |
|
* |
1046 |
< |
* @return the next submission, or null if none |
1046 |
> |
* @return the next submission, or {@code null} if none |
1047 |
|
*/ |
1048 |
|
protected ForkJoinTask<?> pollSubmission() { |
1049 |
|
return submissionQueue.poll(); |
1053 |
|
* Removes all available unexecuted submitted and forked tasks |
1054 |
|
* from scheduling queues and adds them to the given collection, |
1055 |
|
* without altering their execution status. These may include |
1056 |
< |
* artificially generated or wrapped tasks. This method is designed |
1057 |
< |
* to be invoked only when the pool is known to be |
1056 |
> |
* artificially generated or wrapped tasks. This method is |
1057 |
> |
* designed to be invoked only when the pool is known to be |
1058 |
|
* quiescent. Invocations at other times may not remove all |
1059 |
|
* tasks. A failure encountered while attempting to add elements |
1060 |
|
* to collection {@code c} may result in elements being in |
1066 |
|
* @param c the collection to transfer elements into |
1067 |
|
* @return the number of elements transferred |
1068 |
|
*/ |
1069 |
< |
protected int drainTasksTo(Collection<ForkJoinTask<?>> c) { |
1069 |
> |
protected int drainTasksTo(Collection<? super ForkJoinTask<?>> c) { |
1070 |
|
int n = submissionQueue.drainTo(c); |
1071 |
|
ForkJoinWorkerThread[] ws = workers; |
1072 |
|
if (ws != null) { |
1132 |
|
public void shutdown() { |
1133 |
|
checkPermission(); |
1134 |
|
transitionRunStateTo(SHUTDOWN); |
1135 |
< |
if (canTerminateOnShutdown(runControl)) |
1135 |
> |
if (canTerminateOnShutdown(runControl)) { |
1136 |
> |
if (workers == null) { // shutting down before workers created |
1137 |
> |
final ReentrantLock lock = this.workerLock; |
1138 |
> |
lock.lock(); |
1139 |
> |
try { |
1140 |
> |
if (workers == null) { |
1141 |
> |
terminate(); |
1142 |
> |
transitionRunStateTo(TERMINATED); |
1143 |
> |
termination.signalAll(); |
1144 |
> |
} |
1145 |
> |
} finally { |
1146 |
> |
lock.unlock(); |
1147 |
> |
} |
1148 |
> |
} |
1149 |
|
terminateOnShutdown(); |
1150 |
+ |
} |
1151 |
|
} |
1152 |
|
|
1153 |
|
/** |
1154 |
< |
* Attempts to stop all actively executing tasks, and cancels all |
1155 |
< |
* waiting tasks. Tasks that are in the process of being |
1156 |
< |
* submitted or executed concurrently during the course of this |
1157 |
< |
* method may or may not be rejected. Unlike some other executors, |
1158 |
< |
* this method cancels rather than collects non-executed tasks |
1159 |
< |
* upon termination, so always returns an empty list. However, you |
1160 |
< |
* can use method {@code drainTasksTo} before invoking this |
1161 |
< |
* method to transfer unexecuted tasks to another collection. |
1154 |
> |
* Attempts to cancel and/or stop all tasks, and reject all |
1155 |
> |
* subsequently submitted tasks. Tasks that are in the process of |
1156 |
> |
* being submitted or executed concurrently during the course of |
1157 |
> |
* this method may or may not be rejected. This method cancels |
1158 |
> |
* both existing and unexecuted tasks, in order to permit |
1159 |
> |
* termination in the presence of task dependencies. So the method |
1160 |
> |
* always returns an empty list (unlike the case for some other |
1161 |
> |
* Executors). |
1162 |
|
* |
1163 |
|
* @return an empty list |
1164 |
|
* @throws SecurityException if a security manager exists and |
1183 |
|
|
1184 |
|
/** |
1185 |
|
* Returns {@code true} if the process of termination has |
1186 |
< |
* commenced but possibly not yet completed. |
1186 |
> |
* commenced but not yet completed. This method may be useful for |
1187 |
> |
* debugging. A return of {@code true} reported a sufficient |
1188 |
> |
* period after shutdown may indicate that submitted tasks have |
1189 |
> |
* ignored or suppressed interruption, causing this executor not |
1190 |
> |
* to properly terminate. |
1191 |
|
* |
1192 |
< |
* @return {@code true} if terminating |
1192 |
> |
* @return {@code true} if terminating but not yet terminated |
1193 |
|
*/ |
1194 |
|
public boolean isTerminating() { |
1195 |
< |
return runStateOf(runControl) >= TERMINATING; |
1195 |
> |
return runStateOf(runControl) == TERMINATING; |
1196 |
|
} |
1197 |
|
|
1198 |
|
/** |
1205 |
|
} |
1206 |
|
|
1207 |
|
/** |
1208 |
+ |
* Returns true if pool is not terminating or terminated. |
1209 |
+ |
* Used internally to suppress execution when terminating. |
1210 |
+ |
*/ |
1211 |
+ |
final boolean isProcessingTasks() { |
1212 |
+ |
return runStateOf(runControl) < TERMINATING; |
1213 |
+ |
} |
1214 |
+ |
|
1215 |
+ |
/** |
1216 |
|
* Blocks until all tasks have completed execution after a shutdown |
1217 |
|
* request, or the timeout occurs, or the current thread is |
1218 |
|
* interrupted, whichever happens first. |
1266 |
|
transitionRunStateTo(TERMINATED); |
1267 |
|
termination.signalAll(); |
1268 |
|
} |
1269 |
< |
else if (!isTerminating()) { |
1269 |
> |
else if (isProcessingTasks()) { |
1270 |
|
tryShrinkWorkerArray(); |
1271 |
|
tryResumeSpare(true); // allow replacement |
1272 |
|
} |
1507 |
|
final void sync(ForkJoinWorkerThread w) { |
1508 |
|
updateStealCount(w); // Transfer w's count while it is idle |
1509 |
|
|
1510 |
< |
while (!w.isShutdown() && !isTerminating() && !suspendIfSpare(w)) { |
1510 |
> |
while (!w.isShutdown() && isProcessingTasks() && !suspendIfSpare(w)) { |
1511 |
|
long prev = w.lastEventCount; |
1512 |
|
WaitQueueNode node = null; |
1513 |
|
WaitQueueNode h; |
1529 |
|
} |
1530 |
|
|
1531 |
|
/** |
1532 |
< |
* Returns true if worker waiting on sync can proceed: |
1532 |
> |
* Returns {@code true} if worker waiting on sync can proceed: |
1533 |
|
* - on signal (thread == null) |
1534 |
|
* - on event count advance (winning race to notify vs signaller) |
1535 |
|
* - on interrupt |
1537 |
|
* If node was not signalled and event count not advanced on exit, |
1538 |
|
* then we also help advance event count. |
1539 |
|
* |
1540 |
< |
* @return true if node can be released |
1540 |
> |
* @return {@code true} if node can be released |
1541 |
|
*/ |
1542 |
|
final boolean syncIsReleasable(WaitQueueNode node) { |
1543 |
|
long prev = node.count; |
1556 |
|
} |
1557 |
|
|
1558 |
|
/** |
1559 |
< |
* Returns true if a new sync event occurred since last call to |
1560 |
< |
* sync or this method, if so, updating caller's count. |
1559 |
> |
* Returns {@code true} if a new sync event occurred since last |
1560 |
> |
* call to sync or this method, if so, updating caller's count. |
1561 |
|
*/ |
1562 |
|
final boolean hasNewSyncEvent(ForkJoinWorkerThread w) { |
1563 |
|
long lc = w.lastEventCount; |
1607 |
|
while (spareStack == null || !tryResumeSpare(dec)) { |
1608 |
|
int counts = workerCounts; |
1609 |
|
if (dec || (dec = casWorkerCounts(counts, --counts))) { |
1541 |
– |
// CAS cheat |
1610 |
|
if (!needSpare(counts, maintainParallelism)) |
1611 |
|
break; |
1612 |
|
if (joinMe.status < 0) |
1640 |
|
} |
1641 |
|
|
1642 |
|
/** |
1643 |
< |
* Returns true if a spare thread appears to be needed. If |
1644 |
< |
* maintaining parallelism, returns true when the deficit in |
1643 |
> |
* Returns {@code true} if a spare thread appears to be needed. |
1644 |
> |
* If maintaining parallelism, returns true when the deficit in |
1645 |
|
* running threads is more than the surplus of total threads, and |
1646 |
|
* there is apparently some work to do. This self-limiting rule |
1647 |
|
* means that the more threads that have already been added, the |
1711 |
|
for (k = 0; k < len && ws[k] != null; ++k) |
1712 |
|
; |
1713 |
|
} |
1714 |
< |
if (k < len && !isTerminating() && (w = createWorker(k)) != null) { |
1714 |
> |
if (k < len && isProcessingTasks() && (w = createWorker(k)) != null) { |
1715 |
|
ws[k] = w; |
1716 |
|
w.start(); |
1717 |
|
} |
1809 |
|
|
1810 |
|
/** |
1811 |
|
* Interface for extending managed parallelism for tasks running |
1812 |
< |
* in ForkJoinPools. A ManagedBlocker provides two methods. |
1813 |
< |
* Method {@code isReleasable} must return true if blocking is not |
1814 |
< |
* necessary. Method {@code block} blocks the current thread if |
1815 |
< |
* necessary (perhaps internally invoking {@code isReleasable} |
1816 |
< |
* before actually blocking.). |
1812 |
> |
* in {@link ForkJoinPool}s. |
1813 |
> |
* |
1814 |
> |
* <p>A {@code ManagedBlocker} provides two methods. |
1815 |
> |
* Method {@code isReleasable} must return {@code true} if |
1816 |
> |
* blocking is not necessary. Method {@code block} blocks the |
1817 |
> |
* current thread if necessary (perhaps internally invoking |
1818 |
> |
* {@code isReleasable} before actually blocking). |
1819 |
|
* |
1820 |
|
* <p>For example, here is a ManagedBlocker based on a |
1821 |
|
* ReentrantLock: |
1839 |
|
* Possibly blocks the current thread, for example waiting for |
1840 |
|
* a lock or condition. |
1841 |
|
* |
1842 |
< |
* @return true if no additional blocking is necessary (i.e., |
1843 |
< |
* if isReleasable would return true) |
1842 |
> |
* @return {@code true} if no additional blocking is necessary |
1843 |
> |
* (i.e., if isReleasable would return true) |
1844 |
|
* @throws InterruptedException if interrupted while waiting |
1845 |
|
* (the method is not required to do so, but is allowed to) |
1846 |
|
*/ |
1847 |
|
boolean block() throws InterruptedException; |
1848 |
|
|
1849 |
|
/** |
1850 |
< |
* Returns true if blocking is unnecessary. |
1850 |
> |
* Returns {@code true} if blocking is unnecessary. |
1851 |
|
*/ |
1852 |
|
boolean isReleasable(); |
1853 |
|
} |
1854 |
|
|
1855 |
|
/** |
1856 |
|
* Blocks in accord with the given blocker. If the current thread |
1857 |
< |
* is a ForkJoinWorkerThread, this method possibly arranges for a |
1858 |
< |
* spare thread to be activated if necessary to ensure parallelism |
1859 |
< |
* while the current thread is blocked. If |
1860 |
< |
* {@code maintainParallelism} is true and the pool supports |
1861 |
< |
* it ({@link #getMaintainsParallelism}), this method attempts to |
1862 |
< |
* maintain the pool's nominal parallelism. Otherwise it activates |
1863 |
< |
* a thread only if necessary to avoid complete starvation. This |
1864 |
< |
* option may be preferable when blockages use timeouts, or are |
1865 |
< |
* almost always brief. |
1857 |
> |
* is a {@link ForkJoinWorkerThread}, this method possibly |
1858 |
> |
* arranges for a spare thread to be activated if necessary to |
1859 |
> |
* ensure parallelism while the current thread is blocked. |
1860 |
> |
* |
1861 |
> |
* <p>If {@code maintainParallelism} is {@code true} and the pool |
1862 |
> |
* supports it ({@link #getMaintainsParallelism}), this method |
1863 |
> |
* attempts to maintain the pool's nominal parallelism. Otherwise |
1864 |
> |
* it activates a thread only if necessary to avoid complete |
1865 |
> |
* starvation. This option may be preferable when blockages use |
1866 |
> |
* timeouts, or are almost always brief. |
1867 |
|
* |
1868 |
< |
* <p> If the caller is not a ForkJoinTask, this method is behaviorally |
1869 |
< |
* equivalent to |
1868 |
> |
* <p>If the caller is not a {@link ForkJoinTask}, this method is |
1869 |
> |
* behaviorally equivalent to |
1870 |
|
* <pre> {@code |
1871 |
|
* while (!blocker.isReleasable()) |
1872 |
|
* if (blocker.block()) |
1873 |
|
* return; |
1874 |
|
* }</pre> |
1875 |
< |
* If the caller is a ForkJoinTask, then the pool may first |
1876 |
< |
* be expanded to ensure parallelism, and later adjusted. |
1875 |
> |
* |
1876 |
> |
* If the caller is a {@code ForkJoinTask}, then the pool may |
1877 |
> |
* first be expanded to ensure parallelism, and later adjusted. |
1878 |
|
* |
1879 |
|
* @param blocker the blocker |
1880 |
< |
* @param maintainParallelism if true and supported by this pool, |
1881 |
< |
* attempt to maintain the pool's nominal parallelism; otherwise |
1882 |
< |
* activate a thread only if necessary to avoid complete |
1883 |
< |
* starvation. |
1880 |
> |
* @param maintainParallelism if {@code true} and supported by |
1881 |
> |
* this pool, attempt to maintain the pool's nominal parallelism; |
1882 |
> |
* otherwise activate a thread only if necessary to avoid |
1883 |
> |
* complete starvation. |
1884 |
|
* @throws InterruptedException if blocker.block did so |
1885 |
|
*/ |
1886 |
|
public static void managedBlock(ManagedBlocker blocker, |
1906 |
|
do {} while (!blocker.isReleasable() && !blocker.block()); |
1907 |
|
} |
1908 |
|
|
1909 |
< |
// AbstractExecutorService overrides |
1909 |
> |
// AbstractExecutorService overrides. These rely on undocumented |
1910 |
> |
// fact that ForkJoinTask.adapt returns ForkJoinTasks that also |
1911 |
> |
// implement RunnableFuture. |
1912 |
|
|
1913 |
|
protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) { |
1914 |
< |
return new AdaptedRunnable<T>(runnable, value); |
1914 |
> |
return (RunnableFuture<T>) ForkJoinTask.adapt(runnable, value); |
1915 |
|
} |
1916 |
|
|
1917 |
|
protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) { |
1918 |
< |
return new AdaptedCallable<T>(callable); |
1918 |
> |
return (RunnableFuture<T>) ForkJoinTask.adapt(callable); |
1919 |
|
} |
1920 |
|
|
1921 |
+ |
// Unsafe mechanics |
1922 |
|
|
1923 |
< |
// Temporary Unsafe mechanics for preliminary release |
1924 |
< |
private static Unsafe getUnsafe() throws Throwable { |
1925 |
< |
try { |
1926 |
< |
return Unsafe.getUnsafe(); |
1927 |
< |
} catch (SecurityException se) { |
1928 |
< |
try { |
1929 |
< |
return java.security.AccessController.doPrivileged |
1930 |
< |
(new java.security.PrivilegedExceptionAction<Unsafe>() { |
1931 |
< |
public Unsafe run() throws Exception { |
1932 |
< |
return getUnsafePrivileged(); |
1933 |
< |
}}); |
1859 |
< |
} catch (java.security.PrivilegedActionException e) { |
1860 |
< |
throw e.getCause(); |
1861 |
< |
} |
1862 |
< |
} |
1863 |
< |
} |
1864 |
< |
|
1865 |
< |
private static Unsafe getUnsafePrivileged() |
1866 |
< |
throws NoSuchFieldException, IllegalAccessException { |
1867 |
< |
Field f = Unsafe.class.getDeclaredField("theUnsafe"); |
1868 |
< |
f.setAccessible(true); |
1869 |
< |
return (Unsafe) f.get(null); |
1870 |
< |
} |
1871 |
< |
|
1872 |
< |
private static long fieldOffset(String fieldName) |
1873 |
< |
throws NoSuchFieldException { |
1874 |
< |
return UNSAFE.objectFieldOffset |
1875 |
< |
(ForkJoinPool.class.getDeclaredField(fieldName)); |
1876 |
< |
} |
1877 |
< |
|
1878 |
< |
static final Unsafe UNSAFE; |
1879 |
< |
static final long eventCountOffset; |
1880 |
< |
static final long workerCountsOffset; |
1881 |
< |
static final long runControlOffset; |
1882 |
< |
static final long syncStackOffset; |
1883 |
< |
static final long spareStackOffset; |
1884 |
< |
|
1885 |
< |
static { |
1886 |
< |
try { |
1887 |
< |
UNSAFE = getUnsafe(); |
1888 |
< |
eventCountOffset = fieldOffset("eventCount"); |
1889 |
< |
workerCountsOffset = fieldOffset("workerCounts"); |
1890 |
< |
runControlOffset = fieldOffset("runControl"); |
1891 |
< |
syncStackOffset = fieldOffset("syncStack"); |
1892 |
< |
spareStackOffset = fieldOffset("spareStack"); |
1893 |
< |
} catch (Throwable e) { |
1894 |
< |
throw new RuntimeException("Could not initialize intrinsics", e); |
1895 |
< |
} |
1896 |
< |
} |
1923 |
> |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
1924 |
> |
private static final long eventCountOffset = |
1925 |
> |
objectFieldOffset("eventCount", ForkJoinPool.class); |
1926 |
> |
private static final long workerCountsOffset = |
1927 |
> |
objectFieldOffset("workerCounts", ForkJoinPool.class); |
1928 |
> |
private static final long runControlOffset = |
1929 |
> |
objectFieldOffset("runControl", ForkJoinPool.class); |
1930 |
> |
private static final long syncStackOffset = |
1931 |
> |
objectFieldOffset("syncStack",ForkJoinPool.class); |
1932 |
> |
private static final long spareStackOffset = |
1933 |
> |
objectFieldOffset("spareStack", ForkJoinPool.class); |
1934 |
|
|
1935 |
|
private boolean casEventCount(long cmp, long val) { |
1936 |
|
return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val); |
1947 |
|
private boolean casBarrierStack(WaitQueueNode cmp, WaitQueueNode val) { |
1948 |
|
return UNSAFE.compareAndSwapObject(this, syncStackOffset, cmp, val); |
1949 |
|
} |
1950 |
+ |
|
1951 |
+ |
private static long objectFieldOffset(String field, Class<?> klazz) { |
1952 |
+ |
try { |
1953 |
+ |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field)); |
1954 |
+ |
} catch (NoSuchFieldException e) { |
1955 |
+ |
// Convert Exception to corresponding Error |
1956 |
+ |
NoSuchFieldError error = new NoSuchFieldError(field); |
1957 |
+ |
error.initCause(e); |
1958 |
+ |
throw error; |
1959 |
+ |
} |
1960 |
+ |
} |
1961 |
+ |
|
1962 |
+ |
/** |
1963 |
+ |
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
1964 |
+ |
* Replace with a simple call to Unsafe.getUnsafe when integrating |
1965 |
+ |
* into a jdk. |
1966 |
+ |
* |
1967 |
+ |
* @return a sun.misc.Unsafe |
1968 |
+ |
*/ |
1969 |
+ |
private static sun.misc.Unsafe getUnsafe() { |
1970 |
+ |
try { |
1971 |
+ |
return sun.misc.Unsafe.getUnsafe(); |
1972 |
+ |
} catch (SecurityException se) { |
1973 |
+ |
try { |
1974 |
+ |
return java.security.AccessController.doPrivileged |
1975 |
+ |
(new java.security |
1976 |
+ |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
1977 |
+ |
public sun.misc.Unsafe run() throws Exception { |
1978 |
+ |
java.lang.reflect.Field f = sun.misc |
1979 |
+ |
.Unsafe.class.getDeclaredField("theUnsafe"); |
1980 |
+ |
f.setAccessible(true); |
1981 |
+ |
return (sun.misc.Unsafe) f.get(null); |
1982 |
+ |
}}); |
1983 |
+ |
} catch (java.security.PrivilegedActionException e) { |
1984 |
+ |
throw new RuntimeException("Could not initialize intrinsics", |
1985 |
+ |
e.getCause()); |
1986 |
+ |
} |
1987 |
+ |
} |
1988 |
+ |
} |
1989 |
|
} |