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root/jsr166/jsr166/src/jsr166y/ForkJoinPool.java

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.1 by dl, Tue Jan 6 14:30:31 2009 UTC vs.
Revision 1.23 by dl, Sat Jul 25 15:50:57 2009 UTC

#	Line 5 | Line 5
5		*/
6
7		package jsr166y;
8	<	import java.util.*;
8	>
9		import java.util.concurrent.*;
10	<	import java.util.concurrent.locks.*;
11	<	import java.util.concurrent.atomic.*;
12	<	import sun.misc.Unsafe;
13	<	import java.lang.reflect.*;
10	>
11	>	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	>	import java.util.concurrent.atomic.AtomicInteger;
20	>	import java.util.concurrent.atomic.AtomicLong;
21
22		/**
23	<	* Host for a group of ForkJoinWorkerThreads.  A ForkJoinPool provides
24	<	* the entry point for tasks submitted from non-ForkJoinTasks, as well
25	<	* as management and monitoring operations.  Normally a single
26	<	* ForkJoinPool is used for a large number of submitted
27	<	* tasks. Otherwise, use would not usually outweigh the construction
28	<	* and bookkeeping overhead of creating a large set of threads.
23	>	* An {@link ExecutorService} for running {@link ForkJoinTask}s.  A
24	>	* ForkJoinPool provides the entry point for submissions from
25	>	* non-ForkJoinTasks, as well as management and monitoring operations.
26	>	* Normally a single ForkJoinPool is used for a large number of
27	>	* submitted tasks. Otherwise, use would not usually outweigh the
28	>	* construction and bookkeeping overhead of creating a large set of
29	>	* threads.
30		*
31	<	* <p>ForkJoinPools differ from other kinds of Executor mainly in that
32	<	* they provide <em>work-stealing</em>: all threads in the pool
31	>	* <p>ForkJoinPools differ from other kinds of Executors mainly in
32	>	* that they provide <em>work-stealing</em>: all threads in the pool
33		* attempt to find and execute subtasks created by other active tasks
34		* (eventually blocking if none exist). This makes them efficient when
35	<	* most tasks spawn other subtasks (as do most ForkJoinTasks) but
36	<	* possibly less so otherwise. It is however fine to combine execution
37	<	* of some plain Runnable- or Callable- based activities with that of
38	<	* ForkJoinTasks.
35	>	* most tasks spawn other subtasks (as do most ForkJoinTasks), as well
36	>	* as the mixed execution of some plain Runnable- or Callable- based
37	>	* activities along with ForkJoinTasks. When setting
38	>	* {@code setAsyncMode}, a ForkJoinPools may also be appropriate for
39	>	* use with fine-grained tasks that are never joined. Otherwise, other
40	>	* ExecutorService implementations are typically more appropriate
41	>	* choices.
42		*
43		* <p>A ForkJoinPool may be constructed with a given parallelism level
44		* (target pool size), which it attempts to maintain by dynamically
45	<	* adding, suspending, or resuming threads, even if some tasks have
46	<	* blocked waiting to join others. However, no such adjustments are
47	<	* performed in the face of blocked IO or other unmanaged
48	<	* synchronization. The nested ManagedBlocker interface enables
49	<	* extension of the kinds of synchronization accommodated.
50	<	*
51	<	* <p>The target parallelism level may also be set dynamically. You
52	<	* can limit the number of threads dynamically constructed using
53	<	* method <tt>setMaximumPoolSize</tt> and/or
43	<	* <tt>setMaintainParallelism</tt>.
45	>	* adding, suspending, or resuming threads, even if some tasks are
46	>	* waiting to join others. However, no such adjustments are performed
47	>	* in the face of blocked IO or other unmanaged synchronization. The
48	>	* nested {@code ManagedBlocker} interface enables extension of
49	>	* the kinds of synchronization accommodated.  The target parallelism
50	>	* level may also be changed dynamically ({@code setParallelism})
51	>	* and thread construction can be limited using methods
52	>	* {@code setMaximumPoolSize} and/or
53	>	* {@code setMaintainsParallelism}.
54		*
55		* <p>In addition to execution and lifecycle control methods, this
56		* class provides status check methods (for example
57	<	* <tt>getStealCount</tt>) that are intended to aid in developing,
57	>	* {@code getStealCount}) that are intended to aid in developing,
58		* tuning, and monitoring fork/join applications. Also, method
59	<	* <tt>toString</tt> returns indications of pool state in a convenient
60	<	* form for informal monitoring.
59	>	* {@code toString} returns indications of pool state in a
60	>	* convenient form for informal monitoring.
61		*
62		* <p><b>Implementation notes</b>: This implementation restricts the
63	<	* maximum parallelism to 32767. Attempts to create pools with greater
64	<	* than the maximum result in IllegalArgumentExceptions.
63	>	* maximum number of running threads to 32767. Attempts to create
64	>	* pools with greater than the maximum result in
65	>	* IllegalArgumentExceptions.
66	>	*
67	>	* @since 1.7
68	>	* @author Doug Lea
69		*/
70	<	public class ForkJoinPool extends AbstractExecutorService
57	<	implements ExecutorService {
70	>	public class ForkJoinPool extends AbstractExecutorService {
71
72		/*
73		* See the extended comments interspersed below for design,
#	Line 78 | Line 91 | public class ForkJoinPool extends Abstra
91		* Returns a new worker thread operating in the given pool.
92		*
93		* @param pool the pool this thread works in
94	<	* @throws NullPointerException if pool is null;
94	>	* @throws NullPointerException if pool is null
95		*/
96		public ForkJoinWorkerThread newThread(ForkJoinPool pool);
97		}
98
99		/**
100	<	* Default ForkJoinWorkerThreadFactory implementation, creates a
100	>	* Default ForkJoinWorkerThreadFactory implementation; creates a
101		* new ForkJoinWorkerThread.
102		*/
103	<	public static class  DefaultForkJoinWorkerThreadFactory
103	>	static class  DefaultForkJoinWorkerThreadFactory
104		implements ForkJoinWorkerThreadFactory {
105		public ForkJoinWorkerThread newThread(ForkJoinPool pool) {
106		try {
#	Line 99 | Line 112 | public class ForkJoinPool extends Abstra
112		}
113
114		/**
115	<	* The default ForkJoinWorkerThreadFactory, used unless overridden
116	<	* in ForkJoinPool constructors.
115	>	* Creates a new ForkJoinWorkerThread. This factory is used unless
116	>	* overridden in ForkJoinPool constructors.
117		*/
118	<	private static final DefaultForkJoinWorkerThreadFactory
118	>	public static final ForkJoinWorkerThreadFactory
119		defaultForkJoinWorkerThreadFactory =
120		new DefaultForkJoinWorkerThreadFactory();
121
109	–
122		/**
123		* Permission required for callers of methods that may start or
124		* kill threads.
#	Line 131 | Line 143 | public class ForkJoinPool extends Abstra
143		new AtomicInteger();
144
145		/**
146	<	* Array holding all worker threads in the pool. Array size must
147	<	* be a power of two.  Updates and replacements are protected by
148	<	* workerLock, but it is always kept in a consistent enough state
149	<	* to be randomly accessed without locking by workers performing
150	<	* work-stealing.
146	>	* Array holding all worker threads in the pool. Initialized upon
147	>	* first use. Array size must be a power of two.  Updates and
148	>	* replacements are protected by workerLock, but it is always kept
149	>	* in a consistent enough state to be randomly accessed without
150	>	* locking by workers performing work-stealing.
151		*/
152		volatile ForkJoinWorkerThread[] workers;
153
#	Line 151 | Line 163 | public class ForkJoinPool extends Abstra
163
164		/**
165		* The uncaught exception handler used when any worker
166	<	* abrupty terminates
166	>	* abruptly terminates
167		*/
168		private Thread.UncaughtExceptionHandler ueh;
169
#	Line 179 | Line 191 | public class ForkJoinPool extends Abstra
191		private final LinkedTransferQueue<ForkJoinTask<?>> submissionQueue;
192
193		/**
194	<	* Head of Treiber stack for barrier sync. See below for explanation
194	>	* Head of Treiber stack for barrier sync. See below for explanation.
195		*/
196	<	private volatile WaitQueueNode barrierStack;
196	>	private volatile WaitQueueNode syncStack;
197
198		/**
199		* The count for event barrier
#	Line 204 | Line 216 | public class ForkJoinPool extends Abstra
216		private volatile int parallelism;
217
218		/**
219	+	* True if use local fifo, not default lifo, for local polling
220	+	*/
221	+	private volatile boolean locallyFifo;
222	+
223	+	/**
224		* Holds number of total (i.e., created and not yet terminated)
225		* and running (i.e., not blocked on joins or other managed sync)
226		* threads, packed into one int to ensure consistent snapshot when
227		* making decisions about creating and suspending spare
228		* threads. Updated only by CAS.  Note: CASes in
229	<	* updateRunningCount and preJoin running active count is in low
230	<	* word, so need to be modified if this changes
229	>	* updateRunningCount and preJoin assume that running active count
230	>	* is in low word, so need to be modified if this changes.
231		*/
232		private volatile int workerCounts;
233
#	Line 219 | Line 236 | public class ForkJoinPool extends Abstra
236		private static int workerCountsFor(int t, int r) { return (t << 16) + r; }
237
238		/**
239	<	* Add delta (which may be negative) to running count.  This must
239	>	* Adds delta (which may be negative) to running count.  This must
240		* be called before (with negative arg) and after (with positive)
241	<	* any managed synchronization (i.e., mainly, joins)
241	>	* any managed synchronization (i.e., mainly, joins).
242	>	*
243		* @param delta the number to add
244		*/
245		final void updateRunningCount(int delta) {
246		int s;
247	<	do;while (!casWorkerCounts(s = workerCounts, s + delta));
247	>	do {} while (!casWorkerCounts(s = workerCounts, s + delta));
248		}
249
250		/**
251	<	* Add delta (which may be negative) to both total and running
251	>	* Adds delta (which may be negative) to both total and running
252		* count.  This must be called upon creation and termination of
253		* worker threads.
254	+	*
255		* @param delta the number to add
256		*/
257		private void updateWorkerCount(int delta) {
258		int d = delta + (delta << 16); // add to both lo and hi parts
259		int s;
260	<	do;while (!casWorkerCounts(s = workerCounts, s + d));
260	>	do {} while (!casWorkerCounts(s = workerCounts, s + d));
261		}
262
263		/**
#	Line 264 | Line 283 | public class ForkJoinPool extends Abstra
283		private static int runControlFor(int r, int a)   { return (r << 16) + a; }
284
285		/**
286	<	* Increment active count. Called by workers before/during
287	<	* executing tasks.
286	>	* Tries incrementing active count; fails on contention.
287	>	* Called by workers before/during executing tasks.
288	>	*
289	>	* @return true on success
290		*/
291	<	final void incrementActiveCount() {
292	<	int c;
293	<	do;while (!casRunControl(c = runControl, c+1));
291	>	final boolean tryIncrementActiveCount() {
292	>	int c = runControl;
293	>	return casRunControl(c, c+1);
294		}
295
296		/**
297	<	* Decrement active count; possibly trigger termination.
297	>	* Tries decrementing active count; fails on contention.
298	>	* Possibly triggers termination on success.
299		* Called by workers when they can't find tasks.
300	+	*
301	+	* @return true on success
302		*/
303	<	final void decrementActiveCount() {
304	<	int c, nextc;
305	<	do;while (!casRunControl(c = runControl, nextc = c-1));
303	>	final boolean tryDecrementActiveCount() {
304	>	int c = runControl;
305	>	int nextc = c - 1;
306	>	if (!casRunControl(c, nextc))
307	>	return false;
308		if (canTerminateOnShutdown(nextc))
309		terminateOnShutdown();
310	+	return true;
311		}
312
313		/**
314	<	* Return true if argument represents zero active count and
314	>	* Returns true if argument represents zero active count and
315		* nonzero runstate, which is the triggering condition for
316		* terminating on shutdown.
317		*/
318		private static boolean canTerminateOnShutdown(int c) {
319	<	return ((c & -c) >>> 16) != 0; // i.e. least bit is nonzero runState bit
319	>	// i.e. least bit is nonzero runState bit
320	>	return ((c & -c) >>> 16) != 0;
321		}
322
323		/**
#	Line 315 | Line 343 | public class ForkJoinPool extends Abstra
343
344		/**
345		* Creates a ForkJoinPool with a pool size equal to the number of
346	<	* processors available on the system and using the default
347	<	* ForkJoinWorkerThreadFactory,
346	>	* processors available on the system, using the default
347	>	* ForkJoinWorkerThreadFactory.
348	>	*
349		* @throws SecurityException if a security manager exists and
350		*         the caller is not permitted to modify threads
351		*         because it does not hold {@link
352	<	*         java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
352	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
353		*/
354		public ForkJoinPool() {
355		this(Runtime.getRuntime().availableProcessors(),
#	Line 328 | Line 357 | public class ForkJoinPool extends Abstra
357		}
358
359		/**
360	<	* Creates a ForkJoinPool with the indicated parellelism level
361	<	* threads, and using the default ForkJoinWorkerThreadFactory,
360	>	* Creates a ForkJoinPool with the indicated parallelism level
361	>	* threads and using the default ForkJoinWorkerThreadFactory.
362	>	*
363		* @param parallelism the number of worker threads
364		* @throws IllegalArgumentException if parallelism less than or
365		* equal to zero
366		* @throws SecurityException if a security manager exists and
367		*         the caller is not permitted to modify threads
368		*         because it does not hold {@link
369	<	*         java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
369	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
370		*/
371		public ForkJoinPool(int parallelism) {
372		this(parallelism, defaultForkJoinWorkerThreadFactory);
373		}
374
375		/**
376	<	* Creates a ForkJoinPool with a pool size equal to the number of
376	>	* Creates a ForkJoinPool with parallelism equal to the number of
377		* processors available on the system and using the given
378	<	* ForkJoinWorkerThreadFactory,
378	>	* ForkJoinWorkerThreadFactory.
379	>	*
380		* @param factory the factory for creating new threads
381		* @throws NullPointerException if factory is null
382		* @throws SecurityException if a security manager exists and
383		*         the caller is not permitted to modify threads
384		*         because it does not hold {@link
385	<	*         java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
385	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
386		*/
387		public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
388		this(Runtime.getRuntime().availableProcessors(), factory);
389		}
390
391		/**
392	<	* Creates a ForkJoinPool with the indicated target number of
362	<	* worker threads and the given factory.
392	>	* Creates a ForkJoinPool with the given parallelism and factory.
393		*
394		* @param parallelism the targeted number of worker threads
395		* @param factory the factory for creating new threads
396		* @throws IllegalArgumentException if parallelism less than or
397	<	* equal to zero, or greater than implementation limit.
397	>	* equal to zero, or greater than implementation limit
398		* @throws NullPointerException if factory is null
399		* @throws SecurityException if a security manager exists and
400		*         the caller is not permitted to modify threads
401		*         because it does not hold {@link
402	<	*         java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
402	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
403		*/
404		public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
405		if (parallelism <= 0 || parallelism > MAX_THREADS)
#	Line 386 | Line 416 | public class ForkJoinPool extends Abstra
416		this.termination = workerLock.newCondition();
417		this.stealCount = new AtomicLong();
418		this.submissionQueue = new LinkedTransferQueue<ForkJoinTask<?>>();
419	<	createAndStartInitialWorkers(parallelism);
419	>	// worker array and workers are lazily constructed
420		}
421
422		/**
423	<	* Create new worker using factory.
423	>	* Creates a new worker thread using factory.
424	>	*
425		* @param index the index to assign worker
426		* @return new worker, or null of factory failed
427		*/
#	Line 400 | Line 431 | public class ForkJoinPool extends Abstra
431		if (w != null) {
432		w.poolIndex = index;
433		w.setDaemon(true);
434	+	w.setAsyncMode(locallyFifo);
435		w.setName("ForkJoinPool-" + poolNumber + "-worker-" + index);
436		if (h != null)
437		w.setUncaughtExceptionHandler(h);
#	Line 408 | Line 440 | public class ForkJoinPool extends Abstra
440		}
441
442		/**
443	<	* Return a good size for worker array given pool size.
443	>	* Returns a good size for worker array given pool size.
444		* Currently requires size to be a power of two.
445		*/
446	<	private static int arraySizeFor(int ps) {
447	<	return ps <= 1? 1 : (1 << (32 - Integer.numberOfLeadingZeros(ps-1)));
446	>	private static int arraySizeFor(int poolSize) {
447	>	return (poolSize <= 1) ? 1 :
448	>	(1 << (32 - Integer.numberOfLeadingZeros(poolSize-1)));
449		}
450
451		/**
452	<	* Create or resize array if necessary to hold newLength
452	>	* Creates or resizes array if necessary to hold newLength.
453	>	* Call only under exclusion.
454	>	*
455		* @return the array
456		*/
457		private ForkJoinWorkerThread[] ensureWorkerArrayCapacity(int newLength) {
#	Line 430 | Line 465 | public class ForkJoinPool extends Abstra
465		}
466
467		/**
468	<	* Try to shrink workers into smaller array after one or more terminate
468	>	* Tries to shrink workers into smaller array after one or more terminate.
469		*/
470		private void tryShrinkWorkerArray() {
471		ForkJoinWorkerThread[] ws = workers;
472	<	int len = ws.length;
473	<	int last = len - 1;
474	<	while (last >= 0 && ws[last] == null)
475	<	--last;
476	<	int newLength = arraySizeFor(last+1);
477	<	if (newLength < len)
478	<	workers = Arrays.copyOf(ws, newLength);
472	>	if (ws != null) {
473	>	int len = ws.length;
474	>	int last = len - 1;
475	>	while (last >= 0 && ws[last] == null)
476	>	--last;
477	>	int newLength = arraySizeFor(last+1);
478	>	if (newLength < len)
479	>	workers = Arrays.copyOf(ws, newLength);
480	>	}
481		}
482
483		/**
484	<	* Initial worker array and worker creation and startup. (This
448	<	* must be done under lock to avoid interference by some of the
449	<	* newly started threads while creating others.)
484	>	* Initializes workers if necessary.
485		*/
486	<	private void createAndStartInitialWorkers(int ps) {
487	<	final ReentrantLock lock = this.workerLock;
488	<	lock.lock();
489	<	try {
490	<	ForkJoinWorkerThread[] ws = ensureWorkerArrayCapacity(ps);
491	<	for (int i = 0; i < ps; ++i) {
492	<	ForkJoinWorkerThread w = createWorker(i);
493	<	if (w != null) {
494	<	ws[i] = w;
495	<	w.start();
496	<	updateWorkerCount(1);
486	>	final void ensureWorkerInitialization() {
487	>	ForkJoinWorkerThread[] ws = workers;
488	>	if (ws == null) {
489	>	final ReentrantLock lock = this.workerLock;
490	>	lock.lock();
491	>	try {
492	>	ws = workers;
493	>	if (ws == null) {
494	>	int ps = parallelism;
495	>	ws = ensureWorkerArrayCapacity(ps);
496	>	for (int i = 0; i < ps; ++i) {
497	>	ForkJoinWorkerThread w = createWorker(i);
498	>	if (w != null) {
499	>	ws[i] = w;
500	>	w.start();
501	>	updateWorkerCount(1);
502	>	}
503	>	}
504		}
505	+	} finally {
506	+	lock.unlock();
507		}
464	–	} finally {
465	–	lock.unlock();
508		}
509		}
510
#	Line 500 | Line 542 | public class ForkJoinPool extends Abstra
542		}
543		}
544
503	–	/**
504	–	* Sets the handler for internal worker threads that terminate due
505	–	* to unrecoverable errors encountered while executing tasks.
506	–	* Unless set, the current default or ThreadGroup handler is used
507	–	* as handler.
508	–	*
509	–	* @param h the new handler
510	–	* @return the old handler, or null if none
511	–	* @throws SecurityException if a security manager exists and
512	–	*         the caller is not permitted to modify threads
513	–	*         because it does not hold {@link
514	–	*         java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
515	–	*/
516	–	public Thread.UncaughtExceptionHandler
517	–	setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
518	–	checkPermission();
519	–	Thread.UncaughtExceptionHandler old = null;
520	–	final ReentrantLock lock = this.workerLock;
521	–	lock.lock();
522	–	try {
523	–	old = ueh;
524	–	ueh = h;
525	–	ForkJoinWorkerThread[] ws = workers;
526	–	for (int i = 0; i < ws.length; ++i) {
527	–	ForkJoinWorkerThread w = ws[i];
528	–	if (w != null)
529	–	w.setUncaughtExceptionHandler(h);
530	–	}
531	–	} finally {
532	–	lock.unlock();
533	–	}
534	–	return old;
535	–	}
536	–
537	–	/**
538	–	* Returns the handler for internal worker threads that terminate
539	–	* due to unrecoverable errors encountered while executing tasks.
540	–	* @return the handler, or null if none
541	–	*/
542	–	public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
543	–	Thread.UncaughtExceptionHandler h;
544	–	final ReentrantLock lock = this.workerLock;
545	–	lock.lock();
546	–	try {
547	–	h = ueh;
548	–	} finally {
549	–	lock.unlock();
550	–	}
551	–	return h;
552	–	}
553	–
545		// Execution methods
546
547		/**
548		* Common code for execute, invoke and submit
549		*/
550		private <T> void doSubmit(ForkJoinTask<T> task) {
551	+	if (task == null)
552	+	throw new NullPointerException();
553		if (isShutdown())
554		throw new RejectedExecutionException();
555	+	if (workers == null)
556	+	ensureWorkerInitialization();
557		submissionQueue.offer(task);
558	<	signalIdleWorkers(true);
558	>	signalIdleWorkers();
559		}
560
561		/**
562	<	* Performs the given task; returning its result upon completion
562	>	* Performs the given task, returning its result upon completion.
563	>	*
564		* @param task the task
565		* @return the task's result
566		* @throws NullPointerException if task is null
#	Line 577 | Line 573 | public class ForkJoinPool extends Abstra
573
574		/**
575		* Arranges for (asynchronous) execution of the given task.
576	+	*
577		* @param task the task
578		* @throws NullPointerException if task is null
579		* @throws RejectedExecutionException if pool is shut down
#	Line 588 | Line 585 | public class ForkJoinPool extends Abstra
585		// AbstractExecutorService methods
586
587		public void execute(Runnable task) {
588	<	doSubmit(new AdaptedRunnable<Void>(task, null));
588	>	ForkJoinTask<?> job;
589	>	if (task instanceof AdaptedCallable) // avoid re-wrap
590	>	job = (AdaptedCallable<?>)task;
591	>	else if (task instanceof AdaptedRunnable)
592	>	job = (AdaptedRunnable<?>)task;
593	>	else
594	>	job = new AdaptedRunnable<Void>(task, null);
595	>	doSubmit(job);
596		}
597
598		public <T> ForkJoinTask<T> submit(Callable<T> task) {
#	Line 604 | Line 608 | public class ForkJoinPool extends Abstra
608		}
609
610		public ForkJoinTask<?> submit(Runnable task) {
611	<	ForkJoinTask<Void> job = new AdaptedRunnable<Void>(task, null);
611	>	ForkJoinTask<?> job;
612	>	if (task instanceof AdaptedCallable) // avoid re-wrap
613	>	job = (AdaptedCallable<?>)task;
614	>	else if (task instanceof AdaptedRunnable)
615	>	job = (AdaptedRunnable<?>)task;
616	>	else
617	>	job = new AdaptedRunnable<Void>(task, null);
618		doSubmit(job);
619		return job;
620		}
621
622	<	protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
623	<	return new AdaptedRunnable(runnable, value);
624	<	}
625	<
626	<	protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
627	<	return new AdaptedCallable(callable);
622	>	/**
623	>	* Submits a ForkJoinTask for execution.
624	>	*
625	>	* @param task the task to submit
626	>	* @return the task
627	>	* @throws RejectedExecutionException if the task cannot be
628	>	*         scheduled for execution
629	>	* @throws NullPointerException if the task is null
630	>	*/
631	>	public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
632	>	doSubmit(task);
633	>	return task;
634		}
635
636		/**
637		* Adaptor for Runnables. This implements RunnableFuture
638	<	* to be compliant with AbstractExecutorService constraints
638	>	* to be compliant with AbstractExecutorService constraints.
639		*/
640		static final class AdaptedRunnable<T> extends ForkJoinTask<T>
641		implements RunnableFuture<T> {
#	Line 639 | Line 655 | public class ForkJoinPool extends Abstra
655		return true;
656		}
657		public void run() { invoke(); }
658	+	private static final long serialVersionUID = 5232453952276885070L;
659		}
660
661		/**
#	Line 667 | Line 684 | public class ForkJoinPool extends Abstra
684		}
685		}
686		public void run() { invoke(); }
687	+	private static final long serialVersionUID = 2838392045355241008L;
688		}
689
690		public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
691	<	ArrayList<ForkJoinTask<T>> ts =
691	>	ArrayList<ForkJoinTask<T>> forkJoinTasks =
692		new ArrayList<ForkJoinTask<T>>(tasks.size());
693	<	for (Callable<T> c : tasks)
694	<	ts.add(new AdaptedCallable<T>(c));
695	<	invoke(new InvokeAll<T>(ts));
696	<	return (List<Future<T>>)(List)ts;
693	>	for (Callable<T> task : tasks)
694	>	forkJoinTasks.add(new AdaptedCallable<T>(task));
695	>	invoke(new InvokeAll<T>(forkJoinTasks));
696	>
697	>	@SuppressWarnings({"unchecked", "rawtypes"})
698	>	List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks;
699	>	return futures;
700		}
701
702		static final class InvokeAll<T> extends RecursiveAction {
703		final ArrayList<ForkJoinTask<T>> tasks;
704		InvokeAll(ArrayList<ForkJoinTask<T>> tasks) { this.tasks = tasks; }
705		public void compute() {
706	<	try { invokeAll(tasks); } catch(Exception ignore) {}
706	>	try { invokeAll(tasks); }
707	>	catch (Exception ignore) {}
708		}
709	+	private static final long serialVersionUID = -7914297376763021607L;
710		}
711
712		// Configuration and status settings and queries
713
714		/**
715	<	* Returns the factory used for constructing new workers
715	>	* Returns the factory used for constructing new workers.
716		*
717		* @return the factory used for constructing new workers
718		*/
#	Line 698 | Line 721 | public class ForkJoinPool extends Abstra
721		}
722
723		/**
724	<	* Sets the target paralleism level of this pool.
724	>	* Returns the handler for internal worker threads that terminate
725	>	* due to unrecoverable errors encountered while executing tasks.
726	>	*
727	>	* @return the handler, or null if none
728	>	*/
729	>	public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
730	>	Thread.UncaughtExceptionHandler h;
731	>	final ReentrantLock lock = this.workerLock;
732	>	lock.lock();
733	>	try {
734	>	h = ueh;
735	>	} finally {
736	>	lock.unlock();
737	>	}
738	>	return h;
739	>	}
740	>
741	>	/**
742	>	* Sets the handler for internal worker threads that terminate due
743	>	* to unrecoverable errors encountered while executing tasks.
744	>	* Unless set, the current default or ThreadGroup handler is used
745	>	* as handler.
746	>	*
747	>	* @param h the new handler
748	>	* @return the old handler, or null if none
749	>	* @throws SecurityException if a security manager exists and
750	>	*         the caller is not permitted to modify threads
751	>	*         because it does not hold {@link
752	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
753	>	*/
754	>	public Thread.UncaughtExceptionHandler
755	>	setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
756	>	checkPermission();
757	>	Thread.UncaughtExceptionHandler old = null;
758	>	final ReentrantLock lock = this.workerLock;
759	>	lock.lock();
760	>	try {
761	>	old = ueh;
762	>	ueh = h;
763	>	ForkJoinWorkerThread[] ws = workers;
764	>	if (ws != null) {
765	>	for (int i = 0; i < ws.length; ++i) {
766	>	ForkJoinWorkerThread w = ws[i];
767	>	if (w != null)
768	>	w.setUncaughtExceptionHandler(h);
769	>	}
770	>	}
771	>	} finally {
772	>	lock.unlock();
773	>	}
774	>	return old;
775	>	}
776	>
777	>
778	>	/**
779	>	* Sets the target parallelism level of this pool.
780	>	*
781		* @param parallelism the target parallelism
782		* @throws IllegalArgumentException if parallelism less than or
783	<	* equal to zero or greater than maximum size bounds.
783	>	* equal to zero or greater than maximum size bounds
784		* @throws SecurityException if a security manager exists and
785		*         the caller is not permitted to modify threads
786		*         because it does not hold {@link
787	<	*         java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
787	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
788		*/
789		public void setParallelism(int parallelism) {
790		checkPermission();
#	Line 725 | Line 804 | public class ForkJoinPool extends Abstra
804		} finally {
805		lock.unlock();
806		}
807	<	signalIdleWorkers(false);
807	>	signalIdleWorkers();
808		}
809
810		/**
811		* Returns the targeted number of worker threads in this pool.
733	–	* This value does not necessarily reflect transient changes as
734	–	* threads are added, removed, or abruptly terminate.
812		*
813		* @return the targeted number of worker threads in this pool
814		*/
#	Line 742 | Line 819 | public class ForkJoinPool extends Abstra
819		/**
820		* Returns the number of worker threads that have started but not
821		* yet terminated.  This result returned by this method may differ
822	<	* from <tt>getParallelism</tt> when threads are created to
822	>	* from {@code getParallelism} when threads are created to
823		* maintain parallelism when others are cooperatively blocked.
824		*
825		* @return the number of worker threads
#	Line 754 | Line 831 | public class ForkJoinPool extends Abstra
831		/**
832		* Returns the maximum number of threads allowed to exist in the
833		* pool, even if there are insufficient unblocked running threads.
834	+	*
835		* @return the maximum
836		*/
837		public int getMaximumPoolSize() {
#	Line 765 | Line 843 | public class ForkJoinPool extends Abstra
843		* pool, even if there are insufficient unblocked running threads.
844		* Setting this value has no effect on current pool size. It
845		* controls construction of new threads.
846	+	*
847		* @throws IllegalArgumentException if negative or greater then
848	<	* internal implementation limit.
848	>	* internal implementation limit
849		*/
850		public void setMaximumPoolSize(int newMax) {
851		if (newMax < 0 || newMax > MAX_THREADS)
#	Line 779 | Line 858 | public class ForkJoinPool extends Abstra
858		* Returns true if this pool dynamically maintains its target
859		* parallelism level. If false, new threads are added only to
860		* avoid possible starvation.
861	<	* This setting is by default true;
861	>	* This setting is by default true.
862	>	*
863		* @return true if maintains parallelism
864		*/
865		public boolean getMaintainsParallelism() {
#	Line 790 | Line 870 | public class ForkJoinPool extends Abstra
870		* Sets whether this pool dynamically maintains its target
871		* parallelism level. If false, new threads are added only to
872		* avoid possible starvation.
873	+	*
874		* @param enable true to maintains parallelism
875		*/
876		public void setMaintainsParallelism(boolean enable) {
#	Line 797 | Line 878 | public class ForkJoinPool extends Abstra
878		}
879
880		/**
881	<	* Returns the approximate number of worker threads that are not
882	<	* blocked waiting to join tasks or for other managed
881	>	* Establishes local first-in-first-out scheduling mode for forked
882	>	* tasks that are never joined. This mode may be more appropriate
883	>	* than default locally stack-based mode in applications in which
884	>	* worker threads only process asynchronous tasks.  This method is
885	>	* designed to be invoked only when pool is quiescent, and
886	>	* typically only before any tasks are submitted. The effects of
887	>	* invocations at other times may be unpredictable.
888	>	*
889	>	* @param async if true, use locally FIFO scheduling
890	>	* @return the previous mode
891	>	*/
892	>	public boolean setAsyncMode(boolean async) {
893	>	boolean oldMode = locallyFifo;
894	>	locallyFifo = async;
895	>	ForkJoinWorkerThread[] ws = workers;
896	>	if (ws != null) {
897	>	for (int i = 0; i < ws.length; ++i) {
898	>	ForkJoinWorkerThread t = ws[i];
899	>	if (t != null)
900	>	t.setAsyncMode(async);
901	>	}
902	>	}
903	>	return oldMode;
904	>	}
905	>
906	>	/**
907	>	* Returns true if this pool uses local first-in-first-out
908	>	* scheduling mode for forked tasks that are never joined.
909	>	*
910	>	* @return true if this pool uses async mode
911	>	*/
912	>	public boolean getAsyncMode() {
913	>	return locallyFifo;
914	>	}
915	>
916	>	/**
917	>	* Returns an estimate of the number of worker threads that are
918	>	* not blocked waiting to join tasks or for other managed
919		* synchronization.
920		*
921		* @return the number of worker threads
#	Line 808 | Line 925 | public class ForkJoinPool extends Abstra
925		}
926
927		/**
928	<	* Returns the approximate number of threads that are currently
928	>	* Returns an estimate of the number of threads that are currently
929		* stealing or executing tasks. This method may overestimate the
930		* number of active threads.
931	<	* @return the number of active threads.
931	>	*
932	>	* @return the number of active threads
933		*/
934		public int getActiveThreadCount() {
935		return activeCountOf(runControl);
936		}
937
938		/**
939	<	* Returns the approximate number of threads that are currently
939	>	* Returns an estimate of the number of threads that are currently
940		* idle waiting for tasks. This method may underestimate the
941		* number of idle threads.
942	<	* @return the number of idle threads.
942	>	*
943	>	* @return the number of idle threads
944		*/
945		final int getIdleThreadCount() {
946		int c = runningCountOf(workerCounts) - activeCountOf(runControl);
947	<	return (c <= 0)? 0 : c;
947	>	return (c <= 0) ? 0 : c;
948		}
949
950		/**
951		* Returns true if all worker threads are currently idle. An idle
952		* worker is one that cannot obtain a task to execute because none
953		* are available to steal from other threads, and there are no
954	<	* pending submissions to the pool. This method is conservative:
955	<	* It might not return true immediately upon idleness of all
954	>	* pending submissions to the pool. This method is conservative;
955	>	* it might not return true immediately upon idleness of all
956		* threads, but will eventually become true if threads remain
957		* inactive.
958	+	*
959		* @return true if all threads are currently idle
960		*/
961		public boolean isQuiescent() {
#	Line 847 | Line 967 | public class ForkJoinPool extends Abstra
967		* one thread's work queue by another. The reported value
968		* underestimates the actual total number of steals when the pool
969		* is not quiescent. This value may be useful for monitoring and
970	<	* tuning fork/join programs: In general, steal counts should be
970	>	* tuning fork/join programs: in general, steal counts should be
971		* high enough to keep threads busy, but low enough to avoid
972		* overhead and contention across threads.
973	<	* @return the number of steals.
973	>	*
974	>	* @return the number of steals
975		*/
976		public long getStealCount() {
977		return stealCount.get();
978		}
979
980		/**
981	<	* Accumulate steal count from a worker. Call only
982	<	* when worker known to be idle.
981	>	* Accumulates steal count from a worker.
982	>	* Call only when worker known to be idle.
983		*/
984		private void updateStealCount(ForkJoinWorkerThread w) {
985		int sc = w.getAndClearStealCount();
#	Line 867 | Line 988 | public class ForkJoinPool extends Abstra
988		}
989
990		/**
991	<	* Returns the total number of tasks currently held in queues by
992	<	* worker threads (but not including tasks submitted to the pool
993	<	* that have not begun executing). This value is only an
994	<	* approximation, obtained by iterating across all threads in the
995	<	* pool. This method may be useful for tuning task granularities.
996	<	* @return the number of queued tasks.
991	>	* Returns an estimate of the total number of tasks currently held
992	>	* in queues by worker threads (but not including tasks submitted
993	>	* to the pool that have not begun executing). This value is only
994	>	* an approximation, obtained by iterating across all threads in
995	>	* the pool. This method may be useful for tuning task
996	>	* granularities.
997	>	*
998	>	* @return the number of queued tasks
999		*/
1000		public long getQueuedTaskCount() {
1001		long count = 0;
1002		ForkJoinWorkerThread[] ws = workers;
1003	<	for (int i = 0; i < ws.length; ++i) {
1004	<	ForkJoinWorkerThread t = ws[i];
1005	<	if (t != null)
1006	<	count += t.getQueueSize();
1003	>	if (ws != null) {
1004	>	for (int i = 0; i < ws.length; ++i) {
1005	>	ForkJoinWorkerThread t = ws[i];
1006	>	if (t != null)
1007	>	count += t.getQueueSize();
1008	>	}
1009		}
1010		return count;
1011		}
1012
1013		/**
1014	<	* Returns the approximate number tasks submitted to this pool
1014	>	* Returns an estimate of the number tasks submitted to this pool
1015		* that have not yet begun executing. This method takes time
1016		* proportional to the number of submissions.
1017	<	* @return the number of queued submissions.
1017	>	*
1018	>	* @return the number of queued submissions
1019		*/
1020		public int getQueuedSubmissionCount() {
1021		return submissionQueue.size();
#	Line 898 | Line 1024 | public class ForkJoinPool extends Abstra
1024		/**
1025		* Returns true if there are any tasks submitted to this pool
1026		* that have not yet begun executing.
1027	<	* @return <tt>true</tt> if there are any queued submissions.
1027	>	*
1028	>	* @return {@code true} if there are any queued submissions
1029		*/
1030		public boolean hasQueuedSubmissions() {
1031		return !submissionQueue.isEmpty();
#	Line 908 | Line 1035 | public class ForkJoinPool extends Abstra
1035		* Removes and returns the next unexecuted submission if one is
1036		* available.  This method may be useful in extensions to this
1037		* class that re-assign work in systems with multiple pools.
1038	+	*
1039		* @return the next submission, or null if none
1040		*/
1041		protected ForkJoinTask<?> pollSubmission() {
#	Line 915 | Line 1043 | public class ForkJoinPool extends Abstra
1043		}
1044
1045		/**
1046	+	* Removes all available unexecuted submitted and forked tasks
1047	+	* from scheduling queues and adds them to the given collection,
1048	+	* without altering their execution status. These may include
1049	+	* artificially generated or wrapped tasks. This method is designed
1050	+	* to be invoked only when the pool is known to be
1051	+	* quiescent. Invocations at other times may not remove all
1052	+	* tasks. A failure encountered while attempting to add elements
1053	+	* to collection {@code c} may result in elements being in
1054	+	* neither, either or both collections when the associated
1055	+	* exception is thrown.  The behavior of this operation is
1056	+	* undefined if the specified collection is modified while the
1057	+	* operation is in progress.
1058	+	*
1059	+	* @param c the collection to transfer elements into
1060	+	* @return the number of elements transferred
1061	+	*/
1062	+	protected int drainTasksTo(Collection<ForkJoinTask<?>> c) {
1063	+	int n = submissionQueue.drainTo(c);
1064	+	ForkJoinWorkerThread[] ws = workers;
1065	+	if (ws != null) {
1066	+	for (int i = 0; i < ws.length; ++i) {
1067	+	ForkJoinWorkerThread w = ws[i];
1068	+	if (w != null)
1069	+	n += w.drainTasksTo(c);
1070	+	}
1071	+	}
1072	+	return n;
1073	+	}
1074	+
1075	+	/**
1076		* Returns a string identifying this pool, as well as its state,
1077		* including indications of run state, parallelism level, and
1078		* worker and task counts.
#	Line 958 | Line 1116 | public class ForkJoinPool extends Abstra
1116		* Invocation has no additional effect if already shut down.
1117		* Tasks that are in the process of being submitted concurrently
1118		* during the course of this method may or may not be rejected.
1119	+	*
1120		* @throws SecurityException if a security manager exists and
1121		*         the caller is not permitted to modify threads
1122		*         because it does not hold {@link
1123	<	*         java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
1123	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1124		*/
1125		public void shutdown() {
1126		checkPermission();
#	Line 975 | Line 1134 | public class ForkJoinPool extends Abstra
1134		* waiting tasks.  Tasks that are in the process of being
1135		* submitted or executed concurrently during the course of this
1136		* method may or may not be rejected. Unlike some other executors,
1137	<	* this method cancels rather than collects non-executed tasks,
1138	<	* so always returns an empty list.
1137	>	* this method cancels rather than collects non-executed tasks
1138	>	* upon termination, so always returns an empty list. However, you
1139	>	* can use method {@code drainTasksTo} before invoking this
1140	>	* method to transfer unexecuted tasks to another collection.
1141	>	*
1142		* @return an empty list
1143		* @throws SecurityException if a security manager exists and
1144		*         the caller is not permitted to modify threads
1145		*         because it does not hold {@link
1146	<	*         java.lang.RuntimePermission}<tt>("modifyThread")</tt>,
1146	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1147		*/
1148		public List<Runnable> shutdownNow() {
1149		checkPermission();
#	Line 990 | Line 1152 | public class ForkJoinPool extends Abstra
1152		}
1153
1154		/**
1155	<	* Returns <tt>true</tt> if all tasks have completed following shut down.
1155	>	* Returns {@code true} if all tasks have completed following shut down.
1156		*
1157	<	* @return <tt>true</tt> if all tasks have completed following shut down
1157	>	* @return {@code true} if all tasks have completed following shut down
1158		*/
1159		public boolean isTerminated() {
1160		return runStateOf(runControl) == TERMINATED;
1161		}
1162
1163		/**
1164	<	* Returns <tt>true</tt> if the process of termination has
1164	>	* Returns {@code true} if the process of termination has
1165		* commenced but possibly not yet completed.
1166		*
1167	<	* @return <tt>true</tt> if terminating
1167	>	* @return {@code true} if terminating
1168		*/
1169		public boolean isTerminating() {
1170		return runStateOf(runControl) >= TERMINATING;
1171		}
1172
1173		/**
1174	<	* Returns <tt>true</tt> if this pool has been shut down.
1174	>	* Returns {@code true} if this pool has been shut down.
1175		*
1176	<	* @return <tt>true</tt> if this pool has been shut down
1176	>	* @return {@code true} if this pool has been shut down
1177		*/
1178		public boolean isShutdown() {
1179		return runStateOf(runControl) >= SHUTDOWN;
#	Line 1024 | Line 1186 | public class ForkJoinPool extends Abstra
1186		*
1187		* @param timeout the maximum time to wait
1188		* @param unit the time unit of the timeout argument
1189	<	* @return <tt>true</tt> if this executor terminated and
1190	<	*         <tt>false</tt> if the timeout elapsed before termination
1189	>	* @return {@code true} if this executor terminated and
1190	>	*         {@code false} if the timeout elapsed before termination
1191		* @throws InterruptedException if interrupted while waiting
1192		*/
1193		public boolean awaitTermination(long timeout, TimeUnit unit)
#	Line 1049 | Line 1211 | public class ForkJoinPool extends Abstra
1211		// Shutdown and termination support
1212
1213		/**
1214	<	* Callback from terminating worker. Null out the corresponding
1215	<	* workers slot, and if terminating, try to terminate, else try to
1216	<	* shrink workers array.
1214	>	* Callback from terminating worker. Nulls out the corresponding
1215	>	* workers slot, and if terminating, tries to terminate; else
1216	>	* tries to shrink workers array.
1217	>	*
1218		* @param w the worker
1219		*/
1220		final void workerTerminated(ForkJoinWorkerThread w) {
#	Line 1061 | Line 1224 | public class ForkJoinPool extends Abstra
1224		lock.lock();
1225		try {
1226		ForkJoinWorkerThread[] ws = workers;
1227	<	int idx = w.poolIndex;
1228	<	if (idx >= 0 && idx < ws.length && ws[idx] == w)
1229	<	ws[idx] = null;
1230	<	if (totalCountOf(workerCounts) == 0) {
1231	<	terminate(); // no-op if already terminating
1232	<	transitionRunStateTo(TERMINATED);
1233	<	termination.signalAll();
1234	<	}
1235	<	else if (!isTerminating()) {
1236	<	tryShrinkWorkerArray();
1237	<	tryResumeSpare(true); // allow replacement
1227	>	if (ws != null) {
1228	>	int idx = w.poolIndex;
1229	>	if (idx >= 0 && idx < ws.length && ws[idx] == w)
1230	>	ws[idx] = null;
1231	>	if (totalCountOf(workerCounts) == 0) {
1232	>	terminate(); // no-op if already terminating
1233	>	transitionRunStateTo(TERMINATED);
1234	>	termination.signalAll();
1235	>	}
1236	>	else if (!isTerminating()) {
1237	>	tryShrinkWorkerArray();
1238	>	tryResumeSpare(true); // allow replacement
1239	>	}
1240		}
1241		} finally {
1242		lock.unlock();
1243		}
1244	<	signalIdleWorkers(false);
1244	>	signalIdleWorkers();
1245		}
1246
1247		/**
1248	<	* Initiate termination.
1248	>	* Initiates termination.
1249		*/
1250		private void terminate() {
1251		if (transitionRunStateTo(TERMINATING)) {
1252		stopAllWorkers();
1253		resumeAllSpares();
1254	<	signalIdleWorkers(true);
1254	>	signalIdleWorkers();
1255		cancelQueuedSubmissions();
1256		cancelQueuedWorkerTasks();
1257		interruptUnterminatedWorkers();
1258	<	signalIdleWorkers(true); // resignal after interrupt
1258	>	signalIdleWorkers(); // resignal after interrupt
1259		}
1260		}
1261
1262		/**
1263	<	* Possibly terminate when on shutdown state
1263	>	* Possibly terminates when on shutdown state.
1264		*/
1265		private void terminateOnShutdown() {
1266		if (!hasQueuedSubmissions() && canTerminateOnShutdown(runControl))
#	Line 1103 | Line 1268 | public class ForkJoinPool extends Abstra
1268		}
1269
1270		/**
1271	<	* Clear out and cancel submissions
1271	>	* Clears out and cancels submissions.
1272		*/
1273		private void cancelQueuedSubmissions() {
1274		ForkJoinTask<?> task;
#	Line 1112 | Line 1277 | public class ForkJoinPool extends Abstra
1277		}
1278
1279		/**
1280	<	* Clean out worker queues.
1280	>	* Cleans out worker queues.
1281		*/
1282		private void cancelQueuedWorkerTasks() {
1283		final ReentrantLock lock = this.workerLock;
1284		lock.lock();
1285		try {
1286		ForkJoinWorkerThread[] ws = workers;
1287	<	for (int i = 0; i < ws.length; ++i) {
1288	<	ForkJoinWorkerThread t = ws[i];
1289	<	if (t != null)
1290	<	t.cancelTasks();
1287	>	if (ws != null) {
1288	>	for (int i = 0; i < ws.length; ++i) {
1289	>	ForkJoinWorkerThread t = ws[i];
1290	>	if (t != null)
1291	>	t.cancelTasks();
1292	>	}
1293		}
1294		} finally {
1295		lock.unlock();
#	Line 1130 | Line 1297 | public class ForkJoinPool extends Abstra
1297		}
1298
1299		/**
1300	<	* Set each worker's status to terminating. Requires lock to avoid
1301	<	* conflicts with add/remove
1300	>	* Sets each worker's status to terminating. Requires lock to avoid
1301	>	* conflicts with add/remove.
1302		*/
1303		private void stopAllWorkers() {
1304		final ReentrantLock lock = this.workerLock;
1305		lock.lock();
1306		try {
1307		ForkJoinWorkerThread[] ws = workers;
1308	<	for (int i = 0; i < ws.length; ++i) {
1309	<	ForkJoinWorkerThread t = ws[i];
1310	<	if (t != null)
1311	<	t.shutdownNow();
1308	>	if (ws != null) {
1309	>	for (int i = 0; i < ws.length; ++i) {
1310	>	ForkJoinWorkerThread t = ws[i];
1311	>	if (t != null)
1312	>	t.shutdownNow();
1313	>	}
1314		}
1315		} finally {
1316		lock.unlock();
#	Line 1149 | Line 1318 | public class ForkJoinPool extends Abstra
1318		}
1319
1320		/**
1321	<	* Interrupt all unterminated workers.  This is not required for
1321	>	* Interrupts all unterminated workers.  This is not required for
1322		* sake of internal control, but may help unstick user code during
1323		* shutdown.
1324		*/
#	Line 1158 | Line 1327 | public class ForkJoinPool extends Abstra
1327		lock.lock();
1328		try {
1329		ForkJoinWorkerThread[] ws = workers;
1330	<	for (int i = 0; i < ws.length; ++i) {
1331	<	ForkJoinWorkerThread t = ws[i];
1332	<	if (t != null && !t.isTerminated()) {
1333	<	try {
1334	<	t.interrupt();
1335	<	} catch (SecurityException ignore) {
1330	>	if (ws != null) {
1331	>	for (int i = 0; i < ws.length; ++i) {
1332	>	ForkJoinWorkerThread t = ws[i];
1333	>	if (t != null && !t.isTerminated()) {
1334	>	try {
1335	>	t.interrupt();
1336	>	} catch (SecurityException ignore) {
1337	>	}
1338		}
1339		}
1340		}
#	Line 1174 | Line 1345 | public class ForkJoinPool extends Abstra
1345
1346
1347		/*
1348	<	* Nodes for event barrier to manage idle threads.
1348	>	* Nodes for event barrier to manage idle threads.  Queue nodes
1349	>	* are basic Treiber stack nodes, also used for spare stack.
1350		*
1351		* The event barrier has an event count and a wait queue (actually
1352		* a Treiber stack).  Workers are enabled to look for work when
1353	<	* the eventCount is incremented. If they fail to find some,
1354	<	* they may wait for next count. Synchronization events occur only
1355	<	* in enough contexts to maintain overall liveness:
1353	>	* the eventCount is incremented. If they fail to find work, they
1354	>	* may wait for next count. Upon release, threads help others wake
1355	>	* up.
1356	>	*
1357	>	* Synchronization events occur only in enough contexts to
1358	>	* maintain overall liveness:
1359		*
1360		*   - Submission of a new task to the pool
1361	<	*   - Creation or termination of a worker
1361	>	*   - Resizes or other changes to the workers array
1362		*   - pool termination
1363		*   - A worker pushing a task on an empty queue
1364		*
1365	<	* The last case (pushing a task) occurs often enough, and is
1366	<	* heavy enough compared to simple stack pushes to require some
1367	<	* special handling: Method signalNonEmptyWorkerQueue returns
1368	<	* without advancing count if the queue appears to be empty.  This
1369	<	* would ordinarily result in races causing some queued waiters
1370	<	* not to be woken up. To avoid this, a worker in sync
1371	<	* rescans for tasks after being enqueued if it was the first to
1372	<	* enqueue, and aborts the wait if finding one, also helping to
1373	<	* signal others. This works well because the worker has nothing
1374	<	* better to do anyway, and so might as well help alleviate the
1375	<	* overhead and contention on the threads actually doing work.
1376	<	*
1377	<	* Queue nodes are basic Treiber stack nodes, also used for spare
1378	<	* stack.
1365	>	* The case of pushing a task occurs often enough, and is heavy
1366	>	* enough compared to simple stack pushes, to require special
1367	>	* handling: Method signalWork returns without advancing count if
1368	>	* the queue appears to be empty.  This would ordinarily result in
1369	>	* races causing some queued waiters not to be woken up. To avoid
1370	>	* this, the first worker enqueued in method sync (see
1371	>	* syncIsReleasable) rescans for tasks after being enqueued, and
1372	>	* helps signal if any are found. This works well because the
1373	>	* worker has nothing better to do, and so might as well help
1374	>	* alleviate the overhead and contention on the threads actually
1375	>	* doing work.  Also, since event counts increments on task
1376	>	* availability exist to maintain liveness (rather than to force
1377	>	* refreshes etc), it is OK for callers to exit early if
1378	>	* contending with another signaller.
1379		*/
1380		static final class WaitQueueNode {
1381		WaitQueueNode next; // only written before enqueued
1382		volatile ForkJoinWorkerThread thread; // nulled to cancel wait
1383		final long count; // unused for spare stack
1384	<	WaitQueueNode(ForkJoinWorkerThread w, long c) {
1384	>
1385	>	WaitQueueNode(long c, ForkJoinWorkerThread w) {
1386		count = c;
1387		thread = w;
1388		}
1389	<	final boolean signal() {
1389	>
1390	>	/**
1391	>	* Wakes up waiter, returning false if known to already
1392	>	*/
1393	>	boolean signal() {
1394		ForkJoinWorkerThread t = thread;
1395	+	if (t == null)
1396	+	return false;
1397		thread = null;
1398	<	if (t != null) {
1399	<	LockSupport.unpark(t);
1400	<	return true;
1398	>	LockSupport.unpark(t);
1399	>	return true;
1400	>	}
1401	>
1402	>	/**
1403	>	* Awaits release on sync.
1404	>	*/
1405	>	void awaitSyncRelease(ForkJoinPool p) {
1406	>	while (thread != null && !p.syncIsReleasable(this))
1407	>	LockSupport.park(this);
1408	>	}
1409	>
1410	>	/**
1411	>	* Awaits resumption as spare.
1412	>	*/
1413	>	void awaitSpareRelease() {
1414	>	while (thread != null) {
1415	>	if (!Thread.interrupted())
1416	>	LockSupport.park(this);
1417		}
1220	–	return false;
1418		}
1419		}
1420
1421		/**
1422	<	* Release at least one thread waiting for event count to advance,
1423	<	* if one exists. If initial attempt fails, release all threads.
1424	<	* @param all if false, at first try to only release one thread
1425	<	* @return current event
1422	>	* Ensures that no thread is waiting for count to advance from the
1423	>	* current value of eventCount read on entry to this method, by
1424	>	* releasing waiting threads if necessary.
1425	>	*
1426	>	* @return the count
1427		*/
1428	<	private long releaseIdleWorkers(boolean all) {
1429	<	long c;
1430	<	for (;;) {
1431	<	WaitQueueNode q = barrierStack;
1432	<	c = eventCount;
1235	<	long qc;
1236	<	if (q == null || (qc = q.count) >= c)
1237	<	break;
1238	<	if (!all) {
1239	<	if (casBarrierStack(q, q.next) && q.signal())
1240	<	break;
1241	<	all = true;
1242	<	}
1243	<	else if (casBarrierStack(q, null)) {
1428	>	final long ensureSync() {
1429	>	long c = eventCount;
1430	>	WaitQueueNode q;
1431	>	while ((q = syncStack) != null && q.count < c) {
1432	>	if (casBarrierStack(q, null)) {
1433		do {
1434	<	q.signal();
1434	>	q.signal();
1435		} while ((q = q.next) != null);
1436		break;
1437		}
#	Line 1251 | Line 1440 | public class ForkJoinPool extends Abstra
1440		}
1441
1442		/**
1443	<	* Returns current barrier event count
1255	<	* @return current barrier event count
1443	>	* Increments event count and releases waiting threads.
1444		*/
1445	<	final long getEventCount() {
1258	<	long ec = eventCount;
1259	<	releaseIdleWorkers(true); // release to ensure accurate result
1260	<	return ec;
1261	<	}
1262	<
1263	<	/**
1264	<	* Increment event count and release at least one waiting thread,
1265	<	* if one exists (released threads will in turn wake up others).
1266	<	* @param all if true, try to wake up all
1267	<	*/
1268	<	final void signalIdleWorkers(boolean all) {
1445	>	private void signalIdleWorkers() {
1446		long c;
1447	<	do;while (!casEventCount(c = eventCount, c+1));
1448	<	releaseIdleWorkers(all);
1447	>	do {} while (!casEventCount(c = eventCount, c+1));
1448	>	ensureSync();
1449		}
1450
1451		/**
1452	<	* Wake up threads waiting to steal a task. Because method
1453	<	* sync rechecks availability, it is OK to only proceed if
1454	<	* queue appears to be non-empty.
1452	>	* Signals threads waiting to poll a task. Because method sync
1453	>	* rechecks availability, it is OK to only proceed if queue
1454	>	* appears to be non-empty, and OK to skip under contention to
1455	>	* increment count (since some other thread succeeded).
1456		*/
1457	<	final void signalNonEmptyWorkerQueue() {
1280	<	// If CAS fails another signaller must have succeeded
1457	>	final void signalWork() {
1458		long c;
1459	<	if (barrierStack != null && casEventCount(c = eventCount, c+1))
1460	<	releaseIdleWorkers(false);
1459	>	WaitQueueNode q;
1460	>	if (syncStack != null &&
1461	>	casEventCount(c = eventCount, c+1) &&
1462	>	(((q = syncStack) != null && q.count <= c) &&
1463	>	(!casBarrierStack(q, q.next) || !q.signal())))
1464	>	ensureSync();
1465		}
1466
1467		/**
1468	<	* Waits until event count advances from count, or some thread is
1469	<	* waiting on a previous count, or there is stealable work
1470	<	* available. Help wake up others on release.
1468	>	* Waits until event count advances from last value held by
1469	>	* caller, or if excess threads, caller is resumed as spare, or
1470	>	* caller or pool is terminating. Updates caller's event on exit.
1471	>	*
1472		* @param w the calling worker thread
1291	–	* @param prev previous value returned by sync (or 0)
1292	–	* @return current event count
1473		*/
1474	<	final long sync(ForkJoinWorkerThread w, long prev) {
1475	<	updateStealCount(w);
1474	>	final void sync(ForkJoinWorkerThread w) {
1475	>	updateStealCount(w); // Transfer w's count while it is idle
1476
1477	<	while (!w.isShutdown() && !isTerminating() &&
1478	<	(parallelism >= runningCountOf(workerCounts) ||
1299	<	!suspendIfSpare(w))) { // prefer suspend to waiting here
1477	>	while (!w.isShutdown() && !isTerminating() && !suspendIfSpare(w)) {
1478	>	long prev = w.lastEventCount;
1479		WaitQueueNode node = null;
1480	<	boolean queued = false;
1481	<	for (;;) {
1482	<	if (!queued) {
1483	<	if (eventCount != prev)
1484	<	break;
1485	<	WaitQueueNode h = barrierStack;
1486	<	if (h != null && h.count != prev)
1308	<	break; // release below and maybe retry
1309	<	if (node == null)
1310	<	node = new WaitQueueNode(w, prev);
1311	<	queued = casBarrierStack(node.next = h, node);
1312	<	}
1313	<	else if (Thread.interrupted() ||
1314	<	node.thread == null ||
1315	<	(node.next == null && w.prescan()) ||
1316	<	eventCount != prev) {
1317	<	node.thread = null;
1318	<	if (eventCount == prev) // help trigger
1319	<	casEventCount(prev, prev+1);
1480	>	WaitQueueNode h;
1481	>	while (eventCount == prev &&
1482	>	((h = syncStack) == null || h.count == prev)) {
1483	>	if (node == null)
1484	>	node = new WaitQueueNode(prev, w);
1485	>	if (casBarrierStack(node.next = h, node)) {
1486	>	node.awaitSyncRelease(this);
1487		break;
1488		}
1322	–	else
1323	–	LockSupport.park(this);
1489		}
1490	+	long ec = ensureSync();
1491	+	if (ec != prev) {
1492	+	w.lastEventCount = ec;
1493	+	break;
1494	+	}
1495	+	}
1496	+	}
1497	+
1498	+	/**
1499	+	* Returns true if worker waiting on sync can proceed:
1500	+	*  - on signal (thread == null)
1501	+	*  - on event count advance (winning race to notify vs signaller)
1502	+	*  - on interrupt
1503	+	*  - if the first queued node, we find work available
1504	+	* If node was not signalled and event count not advanced on exit,
1505	+	* then we also help advance event count.
1506	+	*
1507	+	* @return true if node can be released
1508	+	*/
1509	+	final boolean syncIsReleasable(WaitQueueNode node) {
1510	+	long prev = node.count;
1511	+	if (!Thread.interrupted() && node.thread != null &&
1512	+	(node.next != null ||
1513	+	!ForkJoinWorkerThread.hasQueuedTasks(workers)) &&
1514	+	eventCount == prev)
1515	+	return false;
1516	+	if (node.thread != null) {
1517	+	node.thread = null;
1518		long ec = eventCount;
1519	<	if (releaseIdleWorkers(false) != prev)
1520	<	return ec;
1519	>	if (prev <= ec) // help signal
1520	>	casEventCount(ec, ec+1);
1521		}
1522	<	return prev; // return old count if aborted
1522	>	return true;
1523	>	}
1524	>
1525	>	/**
1526	>	* Returns true if a new sync event occurred since last call to
1527	>	* sync or this method, if so, updating caller's count.
1528	>	*/
1529	>	final boolean hasNewSyncEvent(ForkJoinWorkerThread w) {
1530	>	long lc = w.lastEventCount;
1531	>	long ec = ensureSync();
1532	>	if (ec == lc)
1533	>	return false;
1534	>	w.lastEventCount = ec;
1535	>	return true;
1536		}
1537
1538		//  Parallelism maintenance
1539
1540		/**
1541	<	* Decrement running count; if too low, add spare.
1541	>	* Decrements running count; if too low, adds spare.
1542		*
1543		* Conceptually, all we need to do here is add or resume a
1544		* spare thread when one is about to block (and remove or
1545		* suspend it later when unblocked -- see suspendIfSpare).
1546		* However, implementing this idea requires coping with
1547	<	* several problems: We have imperfect information about the
1547	>	* several problems: we have imperfect information about the
1548		* states of threads. Some count updates can and usually do
1549		* lag run state changes, despite arrangements to keep them
1550		* accurate (for example, when possible, updating counts
#	Line 1352 | Line 1558 | public class ForkJoinPool extends Abstra
1558		* only be suspended or removed when they are idle, not
1559		* immediately when they aren't needed. So adding threads will
1560		* raise parallelism level for longer than necessary.  Also,
1561	<	* FJ applications often enounter highly transient peaks when
1561	>	* FJ applications often encounter highly transient peaks when
1562		* many threads are blocked joining, but for less time than it
1563		* takes to create or resume spares.
1564		*
#	Line 1361 | Line 1567 | public class ForkJoinPool extends Abstra
1567		* target counts, else create only to avoid starvation
1568		* @return true if joinMe known to be done
1569		*/
1570	<	final boolean preJoin(ForkJoinTask<?> joinMe, boolean maintainParallelism) {
1570	>	final boolean preJoin(ForkJoinTask<?> joinMe,
1571	>	boolean maintainParallelism) {
1572		maintainParallelism &= maintainsParallelism; // overrride
1573		boolean dec = false;  // true when running count decremented
1574		while (spareStack == null || !tryResumeSpare(dec)) {
1575		int counts = workerCounts;
1576	<	if (dec || (dec = casWorkerCounts(counts, --counts))) { // CAS cheat
1576	>	if (dec || (dec = casWorkerCounts(counts, --counts))) {
1577	>	// CAS cheat
1578		if (!needSpare(counts, maintainParallelism))
1579		break;
1580		if (joinMe.status < 0)
#	Line 1381 | Line 1589 | public class ForkJoinPool extends Abstra
1589		/**
1590		* Same idea as preJoin
1591		*/
1592	<	final boolean preBlock(ManagedBlocker blocker, boolean maintainParallelism){
1592	>	final boolean preBlock(ManagedBlocker blocker,
1593	>	boolean maintainParallelism) {
1594		maintainParallelism &= maintainsParallelism;
1595		boolean dec = false;
1596		while (spareStack == null || !tryResumeSpare(dec)) {
#	Line 1405 | Line 1614 | public class ForkJoinPool extends Abstra
1614		* there is apparently some work to do.  This self-limiting rule
1615		* means that the more threads that have already been added, the
1616		* less parallelism we will tolerate before adding another.
1617	+	*
1618		* @param counts current worker counts
1619		* @param maintainParallelism try to maintain parallelism
1620		*/
#	Line 1417 | Line 1627 | public class ForkJoinPool extends Abstra
1627		return (tc < maxPoolSize &&
1628		(rc == 0 || totalSurplus < 0 ||
1629		(maintainParallelism &&
1630	<	runningDeficit > totalSurplus && mayHaveQueuedWork())));
1630	>	runningDeficit > totalSurplus &&
1631	>	ForkJoinWorkerThread.hasQueuedTasks(workers))));
1632		}
1633
1634		/**
1635	<	* Returns true if at least one worker queue appears to be
1636	<	* nonempty. This is expensive but not often called. It is not
1637	<	* critical that this be accurate, but if not, more or fewer
1427	<	* running threads than desired might be maintained.
1428	<	*/
1429	<	private boolean mayHaveQueuedWork() {
1430	<	ForkJoinWorkerThread[] ws = workers;
1431	<	int len = ws.length;
1432	<	ForkJoinWorkerThread v;
1433	<	for (int i = 0; i < len; ++i) {
1434	<	if ((v = ws[i]) != null && v.getRawQueueSize() > 0) {
1435	<	releaseIdleWorkers(false); // help wake up stragglers
1436	<	return true;
1437	<	}
1438	<	}
1439	<	return false;
1440	<	}
1441	<
1442	<	/**
1443	<	* Add a spare worker if lock available and no more than the
1444	<	* expected numbers of threads exist
1635	>	* Adds a spare worker if lock available and no more than the
1636	>	* expected numbers of threads exist.
1637	>	*
1638		* @return true if successful
1639		*/
1640		private boolean tryAddSpare(int expectedCounts) {
#	Line 1474 | Line 1667 | public class ForkJoinPool extends Abstra
1667		}
1668
1669		/**
1670	<	* Add the kth spare worker. On entry, pool coounts are already
1670	>	* Adds the kth spare worker. On entry, pool counts are already
1671		* adjusted to reflect addition.
1672		*/
1673		private void createAndStartSpare(int k) {
#	Line 1486 | Line 1679 | public class ForkJoinPool extends Abstra
1679		for (k = 0; k < len && ws[k] != null; ++k)
1680		;
1681		}
1682	<	if (k < len && (w = createWorker(k)) != null) {
1682	>	if (k < len && !isTerminating() && (w = createWorker(k)) != null) {
1683		ws[k] = w;
1684		w.start();
1685		}
1686		else
1687		updateWorkerCount(-1); // adjust on failure
1688	<	signalIdleWorkers(false);
1688	>	signalIdleWorkers();
1689		}
1690
1691		/**
1692	<	* Suspend calling thread w if there are excess threads.  Called
1693	<	* only from sync.  Spares are enqueued in a Treiber stack
1694	<	* using the same WaitQueueNodes as barriers.  They are resumed
1695	<	* mainly in preJoin, but are also woken on pool events that
1696	<	* require all threads to check run state.
1692	>	* Suspends calling thread w if there are excess threads.  Called
1693	>	* only from sync.  Spares are enqueued in a Treiber stack using
1694	>	* the same WaitQueueNodes as barriers.  They are resumed mainly
1695	>	* in preJoin, but are also woken on pool events that require all
1696	>	* threads to check run state.
1697	>	*
1698		* @param w the caller
1699		*/
1700		private boolean suspendIfSpare(ForkJoinWorkerThread w) {
#	Line 1508 | Line 1702 | public class ForkJoinPool extends Abstra
1702		int s;
1703		while (parallelism < runningCountOf(s = workerCounts)) {
1704		if (node == null)
1705	<	node = new WaitQueueNode(w, 0);
1705	>	node = new WaitQueueNode(0, w);
1706		if (casWorkerCounts(s, s-1)) { // representation-dependent
1707		// push onto stack
1708	<	do;while (!casSpareStack(node.next = spareStack, node));
1515	<
1708	>	do {} while (!casSpareStack(node.next = spareStack, node));
1709		// block until released by resumeSpare
1710	<	while (node.thread != null) {
1518	<	if (!Thread.interrupted())
1519	<	LockSupport.park(this);
1520	<	}
1521	<	w.activate(); // help warm up
1710	>	node.awaitSpareRelease();
1711		return true;
1712		}
1713		}
#	Line 1526 | Line 1715 | public class ForkJoinPool extends Abstra
1715		}
1716
1717		/**
1718	<	* Try to pop and resume a spare thread.
1718	>	* Tries to pop and resume a spare thread.
1719	>	*
1720		* @param updateCount if true, increment running count on success
1721		* @return true if successful
1722		*/
#	Line 1544 | Line 1734 | public class ForkJoinPool extends Abstra
1734		}
1735
1736		/**
1737	<	* Pop and resume all spare threads. Same idea as
1738	<	* releaseIdleWorkers.
1737	>	* Pops and resumes all spare threads. Same idea as ensureSync.
1738	>	*
1739		* @return true if any spares released
1740		*/
1741		private boolean resumeAllSpares() {
#	Line 1563 | Line 1753 | public class ForkJoinPool extends Abstra
1753		}
1754
1755		/**
1756	<	* Pop and shutdown excessive spare threads. Call only while
1756	>	* Pops and shuts down excessive spare threads. Call only while
1757		* holding lock. This is not guaranteed to eliminate all excess
1758		* threads, only those suspended as spares, which are the ones
1759		* unlikely to be needed in the future.
#	Line 1586 | Line 1776 | public class ForkJoinPool extends Abstra
1776		}
1777
1778		/**
1589	–	* Returns approximate number of spares, just for diagnostics.
1590	–	*/
1591	–	private int countSpares() {
1592	–	int sum = 0;
1593	–	for (WaitQueueNode q = spareStack; q != null; q = q.next)
1594	–	++sum;
1595	–	return sum;
1596	–	}
1597	–
1598	–	/**
1779		* Interface for extending managed parallelism for tasks running
1780		* in ForkJoinPools. A ManagedBlocker provides two methods.
1781	<	* Method <tt>isReleasable</tt> must return true if blocking is not
1782	<	* necessary. Method <tt>block</tt> blocks the current thread
1783	<	* if necessary (perhaps internally invoking isReleasable before
1784	<	* actually blocking.).
1781	>	* Method {@code isReleasable} must return true if blocking is not
1782	>	* necessary. Method {@code block} blocks the current thread if
1783	>	* necessary (perhaps internally invoking {@code isReleasable}
1784	>	* before actually blocking.).
1785	>	*
1786		* <p>For example, here is a ManagedBlocker based on a
1787		* ReentrantLock:
1788	<	* <pre>
1789	<	*   class ManagedLocker implements ManagedBlocker {
1790	<	*     final ReentrantLock lock;
1791	<	*     boolean hasLock = false;
1792	<	*     ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1793	<	*     public boolean block() {
1794	<	*        if (!hasLock)
1795	<	*           lock.lock();
1796	<	*        return true;
1797	<	*     }
1798	<	*     public boolean isReleasable() {
1799	<	*        return hasLock || (hasLock = lock.tryLock());
1619	<	*     }
1788	>	*  <pre> {@code
1789	>	* class ManagedLocker implements ManagedBlocker {
1790	>	*   final ReentrantLock lock;
1791	>	*   boolean hasLock = false;
1792	>	*   ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1793	>	*   public boolean block() {
1794	>	*     if (!hasLock)
1795	>	*       lock.lock();
1796	>	*     return true;
1797	>	*   }
1798	>	*   public boolean isReleasable() {
1799	>	*     return hasLock || (hasLock = lock.tryLock());
1800		*   }
1801	<	* </pre>
1801	>	* }}</pre>
1802		*/
1803		public static interface ManagedBlocker {
1804		/**
1805		* Possibly blocks the current thread, for example waiting for
1806		* a lock or condition.
1807	+	*
1808		* @return true if no additional blocking is necessary (i.e.,
1809	<	* if isReleasable would return true).
1809	>	* if isReleasable would return true)
1810		* @throws InterruptedException if interrupted while waiting
1811	<	* (the method is not required to do so, but is allowe to).
1811	>	* (the method is not required to do so, but is allowed to)
1812		*/
1813		boolean block() throws InterruptedException;
1814
#	Line 1642 | Line 1823 | public class ForkJoinPool extends Abstra
1823		* is a ForkJoinWorkerThread, this method possibly arranges for a
1824		* spare thread to be activated if necessary to ensure parallelism
1825		* while the current thread is blocked.  If
1826	<	* <tt>maintainParallelism</tt> is true and the pool supports it
1827	<	* (see <tt>getMaintainsParallelism</tt>), this method attempts to
1828	<	* maintain the pool's nominal parallelism. Otherwise if activates
1826	>	* {@code maintainParallelism} is true and the pool supports
1827	>	* it ({@link #getMaintainsParallelism}), this method attempts to
1828	>	* maintain the pool's nominal parallelism. Otherwise it activates
1829		* a thread only if necessary to avoid complete starvation. This
1830		* option may be preferable when blockages use timeouts, or are
1831		* almost always brief.
1832		*
1833		* <p> If the caller is not a ForkJoinTask, this method is behaviorally
1834		* equivalent to
1835	<	* <pre>
1836	<	*   while (!blocker.isReleasable())
1837	<	*      if (blocker.block())
1838	<	*         return;
1839	<	* </pre>
1835	>	*  <pre> {@code
1836	>	* while (!blocker.isReleasable())
1837	>	*   if (blocker.block())
1838	>	*     return;
1839	>	* }</pre>
1840		* If the caller is a ForkJoinTask, then the pool may first
1841		* be expanded to ensure parallelism, and later adjusted.
1842		*
#	Line 1664 | Line 1845 | public class ForkJoinPool extends Abstra
1845		* attempt to maintain the pool's nominal parallelism; otherwise
1846		* activate a thread only if necessary to avoid complete
1847		* starvation.
1848	<	* @throws InterruptedException if blocker.block did so.
1848	>	* @throws InterruptedException if blocker.block did so
1849		*/
1850		public static void managedBlock(ManagedBlocker blocker,
1851		boolean maintainParallelism)
1852		throws InterruptedException {
1853		Thread t = Thread.currentThread();
1854	<	ForkJoinPool pool = (t instanceof ForkJoinWorkerThread?
1855	<	((ForkJoinWorkerThread)t).pool : null);
1854	>	ForkJoinPool pool = ((t instanceof ForkJoinWorkerThread) ?
1855	>	((ForkJoinWorkerThread) t).pool : null);
1856		if (!blocker.isReleasable()) {
1857		try {
1858		if (pool == null ||
#	Line 1686 | Line 1867 | public class ForkJoinPool extends Abstra
1867
1868		private static void awaitBlocker(ManagedBlocker blocker)
1869		throws InterruptedException {
1870	<	do;while (!blocker.isReleasable() && !blocker.block());
1870	>	do {} while (!blocker.isReleasable() && !blocker.block());
1871	>	}
1872	>
1873	>	// AbstractExecutorService overrides
1874	>
1875	>	protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
1876	>	return new AdaptedRunnable<T>(runnable, value);
1877	>	}
1878	>
1879	>	protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
1880	>	return new AdaptedCallable<T>(callable);
1881		}
1882
1883
1884	<	// Temporary Unsafe mechanics for preliminary release
1884	>	// Unsafe mechanics for jsr166y 3rd party package.
1885	>	private static sun.misc.Unsafe getUnsafe() {
1886	>	try {
1887	>	return sun.misc.Unsafe.getUnsafe();
1888	>	} catch (SecurityException se) {
1889	>	try {
1890	>	return java.security.AccessController.doPrivileged
1891	>	(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1892	>	public sun.misc.Unsafe run() throws Exception {
1893	>	return getUnsafeByReflection();
1894	>	}});
1895	>	} catch (java.security.PrivilegedActionException e) {
1896	>	throw new RuntimeException("Could not initialize intrinsics",
1897	>	e.getCause());
1898	>	}
1899	>	}
1900	>	}
1901
1902	<	static final Unsafe _unsafe;
1903	<	static final long eventCountOffset;
1904	<	static final long workerCountsOffset;
1905	<	static final long runControlOffset;
1906	<	static final long barrierStackOffset;
1907	<	static final long spareStackOffset;
1902	>	private static sun.misc.Unsafe getUnsafeByReflection()
1903	>	throws NoSuchFieldException, IllegalAccessException {
1904	>	java.lang.reflect.Field f =
1905	>	sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
1906	>	f.setAccessible(true);
1907	>	return (sun.misc.Unsafe) f.get(null);
1908	>	}
1909
1910	<	static {
1910	>	private static long fieldOffset(String fieldName, Class<?> klazz) {
1911		try {
1912	<	if (ForkJoinPool.class.getClassLoader() != null) {
1913	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1914	<	f.setAccessible(true);
1915	<	_unsafe = (Unsafe)f.get(null);
1916	<	}
1917	<	else
1710	<	_unsafe = Unsafe.getUnsafe();
1711	<	eventCountOffset = _unsafe.objectFieldOffset
1712	<	(ForkJoinPool.class.getDeclaredField("eventCount"));
1713	<	workerCountsOffset = _unsafe.objectFieldOffset
1714	<	(ForkJoinPool.class.getDeclaredField("workerCounts"));
1715	<	runControlOffset = _unsafe.objectFieldOffset
1716	<	(ForkJoinPool.class.getDeclaredField("runControl"));
1717	<	barrierStackOffset = _unsafe.objectFieldOffset
1718	<	(ForkJoinPool.class.getDeclaredField("barrierStack"));
1719	<	spareStackOffset = _unsafe.objectFieldOffset
1720	<	(ForkJoinPool.class.getDeclaredField("spareStack"));
1721	<	} catch (Exception e) {
1722	<	throw new RuntimeException("Could not initialize intrinsics", e);
1912	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName));
1913	>	} catch (NoSuchFieldException e) {
1914	>	// Convert Exception to Error
1915	>	NoSuchFieldError error = new NoSuchFieldError(fieldName);
1916	>	error.initCause(e);
1917	>	throw error;
1918		}
1919		}
1920
1921	+	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1922	+	static final long eventCountOffset =
1923	+	fieldOffset("eventCount", ForkJoinPool.class);
1924	+	static final long workerCountsOffset =
1925	+	fieldOffset("workerCounts", ForkJoinPool.class);
1926	+	static final long runControlOffset =
1927	+	fieldOffset("runControl", ForkJoinPool.class);
1928	+	static final long syncStackOffset =
1929	+	fieldOffset("syncStack",ForkJoinPool.class);
1930	+	static final long spareStackOffset =
1931	+	fieldOffset("spareStack", ForkJoinPool.class);
1932	+
1933		private boolean casEventCount(long cmp, long val) {
1934	<	return _unsafe.compareAndSwapLong(this, eventCountOffset, cmp, val);
1934	>	return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val);
1935		}
1936		private boolean casWorkerCounts(int cmp, int val) {
1937	<	return _unsafe.compareAndSwapInt(this, workerCountsOffset, cmp, val);
1937	>	return UNSAFE.compareAndSwapInt(this, workerCountsOffset, cmp, val);
1938		}
1939		private boolean casRunControl(int cmp, int val) {
1940	<	return _unsafe.compareAndSwapInt(this, runControlOffset, cmp, val);
1940	>	return UNSAFE.compareAndSwapInt(this, runControlOffset, cmp, val);
1941		}
1942		private boolean casSpareStack(WaitQueueNode cmp, WaitQueueNode val) {
1943	<	return _unsafe.compareAndSwapObject(this, spareStackOffset, cmp, val);
1943	>	return UNSAFE.compareAndSwapObject(this, spareStackOffset, cmp, val);
1944		}
1945		private boolean casBarrierStack(WaitQueueNode cmp, WaitQueueNode val) {
1946	<	return _unsafe.compareAndSwapObject(this, barrierStackOffset, cmp, val);
1946	>	return UNSAFE.compareAndSwapObject(this, syncStackOffset, cmp, val);
1947		}
1948		}

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