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Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.13 by jsr166, Wed Jul 22 01:36:51 2009 UTC vs.
Revision 1.39 by jsr166, Sun Aug 2 17:55:51 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	<	* 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.
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.  Normally a single {@code ForkJoinPool} is
27	>	* used for a large number of submitted tasks. Otherwise, use would
28	>	* not usually outweigh the construction and bookkeeping overhead of
29	>	* creating a large set of threads.
30		*
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), 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.
31	>	* <p>{@code ForkJoinPool}s differ from other kinds of {@link
32	>	* Executor}s mainly in that they provide <em>work-stealing</em>: all
33	>	* threads in the pool attempt to find and execute subtasks created by
34	>	* other active tasks (eventually blocking if none exist). This makes
35	>	* them efficient when most tasks spawn other subtasks (as do most
36	>	* {@code ForkJoinTask}s), as well as the mixed execution of some
37	>	* plain {@code Runnable}- or {@code Callable}- based activities along
38	>	* with {@code ForkJoinTask}s. When setting {@linkplain #setAsyncMode
39	>	* async mode}, a {@code ForkJoinPool} may also be appropriate for use
40	>	* with fine-grained tasks that are never joined. Otherwise, other
41	>	* {@code ExecutorService} implementations are typically more
42	>	* appropriate choices.
43		*
44	<	* <p>A ForkJoinPool may be constructed with a given parallelism level
45	<	* (target pool size), which it attempts to maintain by dynamically
46	<	* adding, suspending, or resuming threads, even if some tasks are
47	<	* waiting to join others. However, no such adjustments are performed
48	<	* in the face of blocked IO or other unmanaged synchronization. The
49	<	* nested {@code ManagedBlocker} interface enables extension of
50	<	* the kinds of synchronization accommodated.  The target parallelism
51	<	* level may also be changed dynamically ({@code setParallelism})
52	<	* and thread construction can be limited using methods
53	<	* {@code setMaximumPoolSize} and/or
54	<	* {@code setMaintainsParallelism}.
44	>	* <p>A {@code ForkJoinPool} may be constructed with a given
45	>	* parallelism level (target pool size), which it attempts to maintain
46	>	* by dynamically adding, suspending, or resuming threads, even if
47	>	* some tasks are waiting to join others. However, no such adjustments
48	>	* are performed in the face of blocked IO or other unmanaged
49	>	* synchronization. The nested {@link ManagedBlocker} interface
50	>	* enables extension of the kinds of synchronization accommodated.
51	>	* The target parallelism level may also be changed dynamically
52	>	* ({@link #setParallelism}) and thread construction can be limited
53	>	* using methods {@link #setMaximumPoolSize} and/or {@link
54	>	* #setMaintainsParallelism}.
55		*
56		* <p>In addition to execution and lifecycle control methods, this
57		* class provides status check methods (for example
58	<	* {@code getStealCount}) that are intended to aid in developing,
58	>	* {@link #getStealCount}) that are intended to aid in developing,
59		* tuning, and monitoring fork/join applications. Also, method
60	<	* {@code toString} returns indications of pool state in a
60	>	* {@link #toString} returns indications of pool state in a
61		* convenient form for informal monitoring.
62		*
63		* <p><b>Implementation notes</b>: This implementation restricts the
64		* maximum number of running threads to 32767. Attempts to create
65		* pools with greater than the maximum result in
66	<	* IllegalArgumentExceptions.
66	>	* {@code IllegalArgumentException}.
67		*
68		* @since 1.7
69		* @author Doug Lea
#	Line 74 | Line 82 | public class ForkJoinPool extends Abstra
82		private static final int MAX_THREADS =  0x7FFF;
83
84		/**
85	<	* Factory for creating new ForkJoinWorkerThreads.  A
86	<	* ForkJoinWorkerThreadFactory must be defined and used for
87	<	* ForkJoinWorkerThread subclasses that extend base functionality
88	<	* or initialize threads with different contexts.
85	>	* Factory for creating new {@link ForkJoinWorkerThread}s.
86	>	* A {@code ForkJoinWorkerThreadFactory} must be defined and used
87	>	* for {@code ForkJoinWorkerThread} subclasses that extend base
88	>	* functionality or initialize threads with different contexts.
89		*/
90		public static interface ForkJoinWorkerThreadFactory {
91		/**
#	Line 90 | Line 98 | public class ForkJoinPool extends Abstra
98		}
99
100		/**
101	<	* Default ForkJoinWorkerThreadFactory implementation, creates a
101	>	* Default ForkJoinWorkerThreadFactory implementation; creates a
102		* new ForkJoinWorkerThread.
103		*/
104		static class  DefaultForkJoinWorkerThreadFactory
#	Line 184 | Line 192 | public class ForkJoinPool extends Abstra
192		private final LinkedTransferQueue<ForkJoinTask<?>> submissionQueue;
193
194		/**
195	<	* Head of Treiber stack for barrier sync. See below for explanation
195	>	* Head of Treiber stack for barrier sync. See below for explanation.
196		*/
197		private volatile WaitQueueNode syncStack;
198
#	Line 219 | Line 227 | public class ForkJoinPool extends Abstra
227		* threads, packed into one int to ensure consistent snapshot when
228		* making decisions about creating and suspending spare
229		* threads. Updated only by CAS.  Note: CASes in
230	<	* updateRunningCount and preJoin running active count is in low
231	<	* word, so need to be modified if this changes
230	>	* updateRunningCount and preJoin assume that running active count
231	>	* is in low word, so need to be modified if this changes.
232		*/
233		private volatile int workerCounts;
234
#	Line 232 | Line 240 | public class ForkJoinPool extends Abstra
240		* Adds delta (which may be negative) to running count.  This must
241		* be called before (with negative arg) and after (with positive)
242		* any managed synchronization (i.e., mainly, joins).
243	+	*
244		* @param delta the number to add
245		*/
246		final void updateRunningCount(int delta) {
247		int s;
248	<	do;while (!casWorkerCounts(s = workerCounts, s + delta));
248	>	do {} while (!casWorkerCounts(s = workerCounts, s + delta));
249		}
250
251		/**
252		* Adds delta (which may be negative) to both total and running
253		* count.  This must be called upon creation and termination of
254		* worker threads.
255	+	*
256		* @param delta the number to add
257		*/
258		private void updateWorkerCount(int delta) {
259		int d = delta + (delta << 16); // add to both lo and hi parts
260		int s;
261	<	do;while (!casWorkerCounts(s = workerCounts, s + d));
261	>	do {} while (!casWorkerCounts(s = workerCounts, s + d));
262		}
263
264		/**
#	Line 274 | Line 284 | public class ForkJoinPool extends Abstra
284		private static int runControlFor(int r, int a)   { return (r << 16) + a; }
285
286		/**
287	<	* Try incrementing active count; fail on contention. Called by
288	<	* workers before/during executing tasks.
287	>	* Tries incrementing active count; fails on contention.
288	>	* Called by workers before/during executing tasks.
289	>	*
290		* @return true on success
291		*/
292		final boolean tryIncrementActiveCount() {
#	Line 287 | Line 298 | public class ForkJoinPool extends Abstra
298		* Tries decrementing active count; fails on contention.
299		* Possibly triggers termination on success.
300		* Called by workers when they can't find tasks.
301	+	*
302		* @return true on success
303		*/
304		final boolean tryDecrementActiveCount() {
#	Line 300 | Line 312 | public class ForkJoinPool extends Abstra
312		}
313
314		/**
315	<	* Returns true if argument represents zero active count and
316	<	* nonzero runstate, which is the triggering condition for
315	>	* Returns {@code true} if argument represents zero active count
316	>	* and nonzero runstate, which is the triggering condition for
317		* terminating on shutdown.
318		*/
319		private static boolean canTerminateOnShutdown(int c) {
320	<	return ((c & -c) >>> 16) != 0; // i.e. least bit is nonzero runState bit
320	>	// i.e. least bit is nonzero runState bit
321	>	return ((c & -c) >>> 16) != 0;
322		}
323
324		/**
#	Line 331 | Line 344 | public class ForkJoinPool extends Abstra
344
345		/**
346		* Creates a ForkJoinPool with a pool size equal to the number of
347	<	* processors available on the system and using the default
348	<	* ForkJoinWorkerThreadFactory,
347	>	* processors available on the system, using the default
348	>	* ForkJoinWorkerThreadFactory.
349	>	*
350		* @throws SecurityException if a security manager exists and
351		*         the caller is not permitted to modify threads
352		*         because it does not hold {@link
353	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
353	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
354		*/
355		public ForkJoinPool() {
356		this(Runtime.getRuntime().availableProcessors(),
#	Line 345 | Line 359 | public class ForkJoinPool extends Abstra
359
360		/**
361		* Creates a ForkJoinPool with the indicated parallelism level
362	<	* threads, and using the default ForkJoinWorkerThreadFactory,
362	>	* threads and using the default ForkJoinWorkerThreadFactory.
363	>	*
364		* @param parallelism the number of worker threads
365		* @throws IllegalArgumentException if parallelism less than or
366		* equal to zero
367		* @throws SecurityException if a security manager exists and
368		*         the caller is not permitted to modify threads
369		*         because it does not hold {@link
370	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
370	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
371		*/
372		public ForkJoinPool(int parallelism) {
373		this(parallelism, defaultForkJoinWorkerThreadFactory);
#	Line 361 | Line 376 | public class ForkJoinPool extends Abstra
376		/**
377		* Creates a ForkJoinPool with parallelism equal to the number of
378		* processors available on the system and using the given
379	<	* ForkJoinWorkerThreadFactory,
379	>	* ForkJoinWorkerThreadFactory.
380	>	*
381		* @param factory the factory for creating new threads
382		* @throws NullPointerException if factory is null
383		* @throws SecurityException if a security manager exists and
384		*         the caller is not permitted to modify threads
385		*         because it does not hold {@link
386	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
386	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
387		*/
388		public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
389		this(Runtime.getRuntime().availableProcessors(), factory);
#	Line 384 | Line 400 | public class ForkJoinPool extends Abstra
400		* @throws SecurityException if a security manager exists and
401		*         the caller is not permitted to modify threads
402		*         because it does not hold {@link
403	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
403	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
404		*/
405		public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
406		if (parallelism <= 0 || parallelism > MAX_THREADS)
#	Line 405 | Line 421 | public class ForkJoinPool extends Abstra
421		}
422
423		/**
424	<	* Create new worker using factory.
424	>	* Creates a new worker thread using factory.
425	>	*
426		* @param index the index to assign worker
427		* @return new worker, or null of factory failed
428		*/
#	Line 427 | Line 444 | public class ForkJoinPool extends Abstra
444		* Returns a good size for worker array given pool size.
445		* Currently requires size to be a power of two.
446		*/
447	<	private static int arraySizeFor(int ps) {
448	<	return ps <= 1? 1 : (1 << (32 - Integer.numberOfLeadingZeros(ps-1)));
447	>	private static int arraySizeFor(int poolSize) {
448	>	return (poolSize <= 1) ? 1 :
449	>	(1 << (32 - Integer.numberOfLeadingZeros(poolSize-1)));
450		}
451
452		/**
453		* Creates or resizes array if necessary to hold newLength.
454	<	* Call only under exclusion or lock.
454	>	* Call only under exclusion.
455	>	*
456		* @return the array
457		*/
458		private ForkJoinWorkerThread[] ensureWorkerArrayCapacity(int newLength) {
#	Line 447 | Line 466 | public class ForkJoinPool extends Abstra
466		}
467
468		/**
469	<	* Try to shrink workers into smaller array after one or more terminate
469	>	* Tries to shrink workers into smaller array after one or more terminate.
470		*/
471		private void tryShrinkWorkerArray() {
472		ForkJoinWorkerThread[] ws = workers;
#	Line 463 | Line 482 | public class ForkJoinPool extends Abstra
482		}
483
484		/**
485	<	* Initialize workers if necessary
485	>	* Initializes workers if necessary.
486		*/
487		final void ensureWorkerInitialization() {
488		ForkJoinWorkerThread[] ws = workers;
#	Line 530 | Line 549 | public class ForkJoinPool extends Abstra
549		* Common code for execute, invoke and submit
550		*/
551		private <T> void doSubmit(ForkJoinTask<T> task) {
552	+	if (task == null)
553	+	throw new NullPointerException();
554		if (isShutdown())
555		throw new RejectedExecutionException();
556		if (workers == null)
#	Line 539 | Line 560 | public class ForkJoinPool extends Abstra
560		}
561
562		/**
563	<	* Performs the given task; returning its result upon completion
563	>	* Performs the given task, returning its result upon completion.
564	>	*
565		* @param task the task
566		* @return the task's result
567		* @throws NullPointerException if task is null
#	Line 552 | Line 574 | public class ForkJoinPool extends Abstra
574
575		/**
576		* Arranges for (asynchronous) execution of the given task.
577	+	*
578		* @param task the task
579		* @throws NullPointerException if task is null
580		* @throws RejectedExecutionException if pool is shut down
581		*/
582	<	public <T> void execute(ForkJoinTask<T> task) {
582	>	public void execute(ForkJoinTask<?> task) {
583		doSubmit(task);
584		}
585
586		// AbstractExecutorService methods
587
588		public void execute(Runnable task) {
589	<	doSubmit(new AdaptedRunnable<Void>(task, null));
589	>	ForkJoinTask<?> job;
590	>	if (task instanceof ForkJoinTask<?>) // avoid re-wrap
591	>	job = (ForkJoinTask<?>) task;
592	>	else
593	>	job = ForkJoinTask.adapt(task, null);
594	>	doSubmit(job);
595		}
596
597		public <T> ForkJoinTask<T> submit(Callable<T> task) {
598	<	ForkJoinTask<T> job = new AdaptedCallable<T>(task);
598	>	ForkJoinTask<T> job = ForkJoinTask.adapt(task);
599		doSubmit(job);
600		return job;
601		}
602
603		public <T> ForkJoinTask<T> submit(Runnable task, T result) {
604	<	ForkJoinTask<T> job = new AdaptedRunnable<T>(task, result);
604	>	ForkJoinTask<T> job = ForkJoinTask.adapt(task, result);
605		doSubmit(job);
606		return job;
607		}
608
609		public ForkJoinTask<?> submit(Runnable task) {
610	<	ForkJoinTask<Void> job = new AdaptedRunnable<Void>(task, null);
610	>	ForkJoinTask<?> job;
611	>	if (task instanceof ForkJoinTask<?>) // avoid re-wrap
612	>	job = (ForkJoinTask<?>) task;
613	>	else
614	>	job = ForkJoinTask.adapt(task, null);
615		doSubmit(job);
616		return job;
617		}
618
619		/**
620	<	* Adaptor for Runnables. This implements RunnableFuture
621	<	* to be compliant with AbstractExecutorService constraints
620	>	* Submits a ForkJoinTask for execution.
621	>	*
622	>	* @param task the task to submit
623	>	* @return the task
624	>	* @throws RejectedExecutionException if the task cannot be
625	>	*         scheduled for execution
626	>	* @throws NullPointerException if the task is null
627		*/
628	<	static final class AdaptedRunnable<T> extends ForkJoinTask<T>
629	<	implements RunnableFuture<T> {
630	<	final Runnable runnable;
594	<	final T resultOnCompletion;
595	<	T result;
596	<	AdaptedRunnable(Runnable runnable, T result) {
597	<	if (runnable == null) throw new NullPointerException();
598	<	this.runnable = runnable;
599	<	this.resultOnCompletion = result;
600	<	}
601	<	public T getRawResult() { return result; }
602	<	public void setRawResult(T v) { result = v; }
603	<	public boolean exec() {
604	<	runnable.run();
605	<	result = resultOnCompletion;
606	<	return true;
607	<	}
608	<	public void run() { invoke(); }
628	>	public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
629	>	doSubmit(task);
630	>	return task;
631		}
632
611	–	/**
612	–	* Adaptor for Callables
613	–	*/
614	–	static final class AdaptedCallable<T> extends ForkJoinTask<T>
615	–	implements RunnableFuture<T> {
616	–	final Callable<T> callable;
617	–	T result;
618	–	AdaptedCallable(Callable<T> callable) {
619	–	if (callable == null) throw new NullPointerException();
620	–	this.callable = callable;
621	–	}
622	–	public T getRawResult() { return result; }
623	–	public void setRawResult(T v) { result = v; }
624	–	public boolean exec() {
625	–	try {
626	–	result = callable.call();
627	–	return true;
628	–	} catch (Error err) {
629	–	throw err;
630	–	} catch (RuntimeException rex) {
631	–	throw rex;
632	–	} catch (Exception ex) {
633	–	throw new RuntimeException(ex);
634	–	}
635	–	}
636	–	public void run() { invoke(); }
637	–	}
633
634		public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
635	<	ArrayList<ForkJoinTask<T>> ts =
635	>	ArrayList<ForkJoinTask<T>> forkJoinTasks =
636		new ArrayList<ForkJoinTask<T>>(tasks.size());
637	<	for (Callable<T> c : tasks)
638	<	ts.add(new AdaptedCallable<T>(c));
639	<	invoke(new InvokeAll<T>(ts));
640	<	return (List<Future<T>>)(List)ts;
637	>	for (Callable<T> task : tasks)
638	>	forkJoinTasks.add(ForkJoinTask.adapt(task));
639	>	invoke(new InvokeAll<T>(forkJoinTasks));
640	>
641	>	@SuppressWarnings({"unchecked", "rawtypes"})
642	>	List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks;
643	>	return futures;
644		}
645
646		static final class InvokeAll<T> extends RecursiveAction {
647		final ArrayList<ForkJoinTask<T>> tasks;
648		InvokeAll(ArrayList<ForkJoinTask<T>> tasks) { this.tasks = tasks; }
649		public void compute() {
650	<	try { invokeAll(tasks); } catch(Exception ignore) {}
650	>	try { invokeAll(tasks); }
651	>	catch (Exception ignore) {}
652		}
653	+	private static final long serialVersionUID = -7914297376763021607L;
654		}
655
656		// Configuration and status settings and queries
657
658		/**
659	<	* Returns the factory used for constructing new workers
659	>	* Returns the factory used for constructing new workers.
660		*
661		* @return the factory used for constructing new workers
662		*/
#	Line 667 | Line 667 | public class ForkJoinPool extends Abstra
667		/**
668		* Returns the handler for internal worker threads that terminate
669		* due to unrecoverable errors encountered while executing tasks.
670	<	* @return the handler, or null if none
670	>	*
671	>	* @return the handler, or {@code null} if none
672		*/
673		public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
674		Thread.UncaughtExceptionHandler h;
#	Line 688 | Line 689 | public class ForkJoinPool extends Abstra
689		* as handler.
690		*
691		* @param h the new handler
692	<	* @return the old handler, or null if none
692	>	* @return the old handler, or {@code null} if none
693		* @throws SecurityException if a security manager exists and
694		*         the caller is not permitted to modify threads
695		*         because it does not hold {@link
696	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
696	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
697		*/
698		public Thread.UncaughtExceptionHandler
699		setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
#	Line 720 | Line 721 | public class ForkJoinPool extends Abstra
721
722		/**
723		* Sets the target parallelism level of this pool.
724	+	*
725		* @param parallelism the target parallelism
726		* @throws IllegalArgumentException if parallelism less than or
727		* equal to zero or greater than maximum size bounds
728		* @throws SecurityException if a security manager exists and
729		*         the caller is not permitted to modify threads
730		*         because it does not hold {@link
731	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
731	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
732		*/
733		public void setParallelism(int parallelism) {
734		checkPermission();
#	Line 761 | Line 763 | public class ForkJoinPool extends Abstra
763		/**
764		* Returns the number of worker threads that have started but not
765		* yet terminated.  This result returned by this method may differ
766	<	* from {@code getParallelism} when threads are created to
766	>	* from {@link #getParallelism} when threads are created to
767		* maintain parallelism when others are cooperatively blocked.
768		*
769		* @return the number of worker threads
#	Line 773 | Line 775 | public class ForkJoinPool extends Abstra
775		/**
776		* Returns the maximum number of threads allowed to exist in the
777		* pool, even if there are insufficient unblocked running threads.
778	+	*
779		* @return the maximum
780		*/
781		public int getMaximumPoolSize() {
#	Line 784 | Line 787 | public class ForkJoinPool extends Abstra
787		* pool, even if there are insufficient unblocked running threads.
788		* Setting this value has no effect on current pool size. It
789		* controls construction of new threads.
790	<	* @throws IllegalArgumentException if negative or greater then
790	>	*
791	>	* @throws IllegalArgumentException if negative or greater than
792		* internal implementation limit
793		*/
794		public void setMaximumPoolSize(int newMax) {
#	Line 795 | Line 799 | public class ForkJoinPool extends Abstra
799
800
801		/**
802	<	* Returns true if this pool dynamically maintains its target
803	<	* parallelism level. If false, new threads are added only to
804	<	* avoid possible starvation.
805	<	* This setting is by default true;
806	<	* @return true if maintains parallelism
802	>	* Returns {@code true} if this pool dynamically maintains its
803	>	* target parallelism level. If false, new threads are added only
804	>	* to avoid possible starvation.  This setting is by default true.
805	>	*
806	>	* @return {@code true} if maintains parallelism
807		*/
808		public boolean getMaintainsParallelism() {
809		return maintainsParallelism;
#	Line 809 | Line 813 | public class ForkJoinPool extends Abstra
813		* Sets whether this pool dynamically maintains its target
814		* parallelism level. If false, new threads are added only to
815		* avoid possible starvation.
816	<	* @param enable true to maintains parallelism
816	>	*
817	>	* @param enable {@code true} to maintain parallelism
818		*/
819		public void setMaintainsParallelism(boolean enable) {
820		maintainsParallelism = enable;
#	Line 820 | Line 825 | public class ForkJoinPool extends Abstra
825		* tasks that are never joined. This mode may be more appropriate
826		* than default locally stack-based mode in applications in which
827		* worker threads only process asynchronous tasks.  This method is
828	<	* designed to be invoked only when pool is quiescent, and
828	>	* designed to be invoked only when the pool is quiescent, and
829		* typically only before any tasks are submitted. The effects of
830		* invocations at other times may be unpredictable.
831		*
832	<	* @param async if true, use locally FIFO scheduling
832	>	* @param async if {@code true}, use locally FIFO scheduling
833		* @return the previous mode
834	+	* @see #getAsyncMode
835		*/
836		public boolean setAsyncMode(boolean async) {
837		boolean oldMode = locallyFifo;
#	Line 842 | Line 848 | public class ForkJoinPool extends Abstra
848		}
849
850		/**
851	<	* Returns true if this pool uses local first-in-first-out
851	>	* Returns {@code true} if this pool uses local first-in-first-out
852		* scheduling mode for forked tasks that are never joined.
853		*
854	<	* @return true if this pool uses async mode
854	>	* @return {@code true} if this pool uses async mode
855	>	* @see #setAsyncMode
856		*/
857		public boolean getAsyncMode() {
858		return locallyFifo;
#	Line 866 | Line 873 | public class ForkJoinPool extends Abstra
873		* Returns an estimate of the number of threads that are currently
874		* stealing or executing tasks. This method may overestimate the
875		* number of active threads.
876	+	*
877		* @return the number of active threads
878		*/
879		public int getActiveThreadCount() {
#	Line 876 | Line 884 | public class ForkJoinPool extends Abstra
884		* Returns an estimate of the number of threads that are currently
885		* idle waiting for tasks. This method may underestimate the
886		* number of idle threads.
887	+	*
888		* @return the number of idle threads
889		*/
890		final int getIdleThreadCount() {
891		int c = runningCountOf(workerCounts) - activeCountOf(runControl);
892	<	return (c <= 0)? 0 : c;
892	>	return (c <= 0) ? 0 : c;
893		}
894
895		/**
896	<	* Returns true if all worker threads are currently idle. An idle
897	<	* worker is one that cannot obtain a task to execute because none
898	<	* are available to steal from other threads, and there are no
899	<	* pending submissions to the pool. This method is conservative:
900	<	* It might not return true immediately upon idleness of all
901	<	* threads, but will eventually become true if threads remain
902	<	* inactive.
903	<	* @return true if all threads are currently idle
896	>	* Returns {@code true} if all worker threads are currently idle.
897	>	* An idle worker is one that cannot obtain a task to execute
898	>	* because none are available to steal from other threads, and
899	>	* there are no pending submissions to the pool. This method is
900	>	* conservative; it might not return {@code true} immediately upon
901	>	* idleness of all threads, but will eventually become true if
902	>	* threads remain inactive.
903	>	*
904	>	* @return {@code true} if all threads are currently idle
905		*/
906		public boolean isQuiescent() {
907		return activeCountOf(runControl) == 0;
#	Line 902 | Line 912 | public class ForkJoinPool extends Abstra
912		* one thread's work queue by another. The reported value
913		* underestimates the actual total number of steals when the pool
914		* is not quiescent. This value may be useful for monitoring and
915	<	* tuning fork/join programs: In general, steal counts should be
915	>	* tuning fork/join programs: in general, steal counts should be
916		* high enough to keep threads busy, but low enough to avoid
917		* overhead and contention across threads.
918	+	*
919		* @return the number of steals
920		*/
921		public long getStealCount() {
#	Line 912 | Line 923 | public class ForkJoinPool extends Abstra
923		}
924
925		/**
926	<	* Accumulate steal count from a worker. Call only
927	<	* when worker known to be idle.
926	>	* Accumulates steal count from a worker.
927	>	* Call only when worker known to be idle.
928		*/
929		private void updateStealCount(ForkJoinWorkerThread w) {
930		int sc = w.getAndClearStealCount();
#	Line 928 | Line 939 | public class ForkJoinPool extends Abstra
939		* an approximation, obtained by iterating across all threads in
940		* the pool. This method may be useful for tuning task
941		* granularities.
942	+	*
943		* @return the number of queued tasks
944		*/
945		public long getQueuedTaskCount() {
#	Line 947 | Line 959 | public class ForkJoinPool extends Abstra
959		* Returns an estimate of the number tasks submitted to this pool
960		* that have not yet begun executing. This method takes time
961		* proportional to the number of submissions.
962	+	*
963		* @return the number of queued submissions
964		*/
965		public int getQueuedSubmissionCount() {
#	Line 954 | Line 967 | public class ForkJoinPool extends Abstra
967		}
968
969		/**
970	<	* Returns true if there are any tasks submitted to this pool
971	<	* that have not yet begun executing.
970	>	* Returns {@code true} if there are any tasks submitted to this
971	>	* pool that have not yet begun executing.
972	>	*
973		* @return {@code true} if there are any queued submissions
974		*/
975		public boolean hasQueuedSubmissions() {
#	Line 966 | Line 980 | public class ForkJoinPool extends Abstra
980		* Removes and returns the next unexecuted submission if one is
981		* available.  This method may be useful in extensions to this
982		* class that re-assign work in systems with multiple pools.
983	<	* @return the next submission, or null if none
983	>	*
984	>	* @return the next submission, or {@code null} if none
985		*/
986		protected ForkJoinTask<?> pollSubmission() {
987		return submissionQueue.poll();
#	Line 985 | Line 1000 | public class ForkJoinPool extends Abstra
1000		* exception is thrown.  The behavior of this operation is
1001		* undefined if the specified collection is modified while the
1002		* operation is in progress.
1003	+	*
1004		* @param c the collection to transfer elements into
1005		* @return the number of elements transferred
1006		*/
1007	<	protected int drainTasksTo(Collection<ForkJoinTask<?>> c) {
1007	>	protected int drainTasksTo(Collection<? super ForkJoinTask<?>> c) {
1008		int n = submissionQueue.drainTo(c);
1009		ForkJoinWorkerThread[] ws = workers;
1010		if (ws != null) {
#	Line 1045 | Line 1061 | public class ForkJoinPool extends Abstra
1061		* Invocation has no additional effect if already shut down.
1062		* Tasks that are in the process of being submitted concurrently
1063		* during the course of this method may or may not be rejected.
1064	+	*
1065		* @throws SecurityException if a security manager exists and
1066		*         the caller is not permitted to modify threads
1067		*         because it does not hold {@link
1068	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1068	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1069		*/
1070		public void shutdown() {
1071		checkPermission();
1072		transitionRunStateTo(SHUTDOWN);
1073	<	if (canTerminateOnShutdown(runControl))
1073	>	if (canTerminateOnShutdown(runControl)) {
1074	>	if (workers == null) { // shutting down before workers created
1075	>	final ReentrantLock lock = this.workerLock;
1076	>	lock.lock();
1077	>	try {
1078	>	if (workers == null) {
1079	>	terminate();
1080	>	transitionRunStateTo(TERMINATED);
1081	>	termination.signalAll();
1082	>	}
1083	>	} finally {
1084	>	lock.unlock();
1085	>	}
1086	>	}
1087		terminateOnShutdown();
1088	+	}
1089		}
1090
1091		/**
#	Line 1064 | Line 1095 | public class ForkJoinPool extends Abstra
1095		* method may or may not be rejected. Unlike some other executors,
1096		* this method cancels rather than collects non-executed tasks
1097		* upon termination, so always returns an empty list. However, you
1098	<	* can use method {@code drainTasksTo} before invoking this
1098	>	* can use method {@link #drainTasksTo} before invoking this
1099		* method to transfer unexecuted tasks to another collection.
1100	+	*
1101		* @return an empty list
1102		* @throws SecurityException if a security manager exists and
1103		*         the caller is not permitted to modify threads
1104		*         because it does not hold {@link
1105	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1105	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1106		*/
1107		public List<Runnable> shutdownNow() {
1108		checkPermission();
#	Line 1138 | Line 1170 | public class ForkJoinPool extends Abstra
1170		// Shutdown and termination support
1171
1172		/**
1173	<	* Callback from terminating worker. Null out the corresponding
1174	<	* workers slot, and if terminating, try to terminate, else try to
1175	<	* shrink workers array.
1173	>	* Callback from terminating worker. Nulls out the corresponding
1174	>	* workers slot, and if terminating, tries to terminate; else
1175	>	* tries to shrink workers array.
1176	>	*
1177		* @param w the worker
1178		*/
1179		final void workerTerminated(ForkJoinWorkerThread w) {
#	Line 1171 | Line 1204 | public class ForkJoinPool extends Abstra
1204		}
1205
1206		/**
1207	<	* Initiate termination.
1207	>	* Initiates termination.
1208		*/
1209		private void terminate() {
1210		if (transitionRunStateTo(TERMINATING)) {
#	Line 1348 | Line 1381 | public class ForkJoinPool extends Abstra
1381		* Ensures that no thread is waiting for count to advance from the
1382		* current value of eventCount read on entry to this method, by
1383		* releasing waiting threads if necessary.
1384	+	*
1385		* @return the count
1386		*/
1387		final long ensureSync() {
#	Line 1369 | Line 1403 | public class ForkJoinPool extends Abstra
1403		*/
1404		private void signalIdleWorkers() {
1405		long c;
1406	<	do;while (!casEventCount(c = eventCount, c+1));
1406	>	do {} while (!casEventCount(c = eventCount, c+1));
1407		ensureSync();
1408		}
1409
#	Line 1393 | Line 1427 | public class ForkJoinPool extends Abstra
1427		* Waits until event count advances from last value held by
1428		* caller, or if excess threads, caller is resumed as spare, or
1429		* caller or pool is terminating. Updates caller's event on exit.
1430	+	*
1431		* @param w the calling worker thread
1432		*/
1433		final void sync(ForkJoinWorkerThread w) {
#	Line 1420 | Line 1455 | public class ForkJoinPool extends Abstra
1455		}
1456
1457		/**
1458	<	* Returns true if worker waiting on sync can proceed:
1458	>	* Returns {@code true} if worker waiting on sync can proceed:
1459		*  - on signal (thread == null)
1460		*  - on event count advance (winning race to notify vs signaller)
1461	<	*  - on Interrupt
1461	>	*  - on interrupt
1462		*  - if the first queued node, we find work available
1463		* If node was not signalled and event count not advanced on exit,
1464		* then we also help advance event count.
1465	<	* @return true if node can be released
1465	>	*
1466	>	* @return {@code true} if node can be released
1467		*/
1468		final boolean syncIsReleasable(WaitQueueNode node) {
1469		long prev = node.count;
#	Line 1446 | Line 1482 | public class ForkJoinPool extends Abstra
1482		}
1483
1484		/**
1485	<	* Returns true if a new sync event occurred since last call to
1486	<	* sync or this method, if so, updating caller's count.
1485	>	* Returns {@code true} if a new sync event occurred since last
1486	>	* call to sync or this method, if so, updating caller's count.
1487		*/
1488		final boolean hasNewSyncEvent(ForkJoinWorkerThread w) {
1489		long lc = w.lastEventCount;
#	Line 1467 | Line 1503 | public class ForkJoinPool extends Abstra
1503		* spare thread when one is about to block (and remove or
1504		* suspend it later when unblocked -- see suspendIfSpare).
1505		* However, implementing this idea requires coping with
1506	<	* several problems: We have imperfect information about the
1506	>	* several problems: we have imperfect information about the
1507		* states of threads. Some count updates can and usually do
1508		* lag run state changes, despite arrangements to keep them
1509		* accurate (for example, when possible, updating counts
#	Line 1490 | Line 1526 | public class ForkJoinPool extends Abstra
1526		* target counts, else create only to avoid starvation
1527		* @return true if joinMe known to be done
1528		*/
1529	<	final boolean preJoin(ForkJoinTask<?> joinMe, boolean maintainParallelism) {
1529	>	final boolean preJoin(ForkJoinTask<?> joinMe,
1530	>	boolean maintainParallelism) {
1531		maintainParallelism &= maintainsParallelism; // overrride
1532		boolean dec = false;  // true when running count decremented
1533		while (spareStack == null || !tryResumeSpare(dec)) {
1534		int counts = workerCounts;
1535	<	if (dec || (dec = casWorkerCounts(counts, --counts))) { // CAS cheat
1535	>	if (dec || (dec = casWorkerCounts(counts, --counts))) {
1536	>	// CAS cheat
1537		if (!needSpare(counts, maintainParallelism))
1538		break;
1539		if (joinMe.status < 0)
#	Line 1510 | Line 1548 | public class ForkJoinPool extends Abstra
1548		/**
1549		* Same idea as preJoin
1550		*/
1551	<	final boolean preBlock(ManagedBlocker blocker, boolean maintainParallelism){
1551	>	final boolean preBlock(ManagedBlocker blocker,
1552	>	boolean maintainParallelism) {
1553		maintainParallelism &= maintainsParallelism;
1554		boolean dec = false;
1555		while (spareStack == null || !tryResumeSpare(dec)) {
#	Line 1528 | Line 1567 | public class ForkJoinPool extends Abstra
1567		}
1568
1569		/**
1570	<	* Returns true if a spare thread appears to be needed.  If
1571	<	* maintaining parallelism, returns true when the deficit in
1570	>	* Returns {@code true} if a spare thread appears to be needed.
1571	>	* If maintaining parallelism, returns true when the deficit in
1572		* running threads is more than the surplus of total threads, and
1573		* there is apparently some work to do.  This self-limiting rule
1574		* means that the more threads that have already been added, the
1575		* less parallelism we will tolerate before adding another.
1576	+	*
1577		* @param counts current worker counts
1578		* @param maintainParallelism try to maintain parallelism
1579		*/
#	Line 1553 | Line 1593 | public class ForkJoinPool extends Abstra
1593		/**
1594		* Adds a spare worker if lock available and no more than the
1595		* expected numbers of threads exist.
1596	+	*
1597		* @return true if successful
1598		*/
1599		private boolean tryAddSpare(int expectedCounts) {
#	Line 1612 | Line 1653 | public class ForkJoinPool extends Abstra
1653		* the same WaitQueueNodes as barriers.  They are resumed mainly
1654		* in preJoin, but are also woken on pool events that require all
1655		* threads to check run state.
1656	+	*
1657		* @param w the caller
1658		*/
1659		private boolean suspendIfSpare(ForkJoinWorkerThread w) {
#	Line 1622 | Line 1664 | public class ForkJoinPool extends Abstra
1664		node = new WaitQueueNode(0, w);
1665		if (casWorkerCounts(s, s-1)) { // representation-dependent
1666		// push onto stack
1667	<	do;while (!casSpareStack(node.next = spareStack, node));
1667	>	do {} while (!casSpareStack(node.next = spareStack, node));
1668		// block until released by resumeSpare
1669		node.awaitSpareRelease();
1670		return true;
#	Line 1633 | Line 1675 | public class ForkJoinPool extends Abstra
1675
1676		/**
1677		* Tries to pop and resume a spare thread.
1678	+	*
1679		* @param updateCount if true, increment running count on success
1680		* @return true if successful
1681		*/
#	Line 1651 | Line 1694 | public class ForkJoinPool extends Abstra
1694
1695		/**
1696		* Pops and resumes all spare threads. Same idea as ensureSync.
1697	+	*
1698		* @return true if any spares released
1699		*/
1700		private boolean resumeAllSpares() {
#	Line 1692 | Line 1736 | public class ForkJoinPool extends Abstra
1736
1737		/**
1738		* Interface for extending managed parallelism for tasks running
1739	<	* in ForkJoinPools. A ManagedBlocker provides two methods.
1740	<	* Method {@code isReleasable} must return true if blocking is not
1741	<	* necessary. Method {@code block} blocks the current thread
1742	<	* if necessary (perhaps internally invoking isReleasable before
1743	<	* actually blocking.).
1739	>	* in {@link ForkJoinPool}s.
1740	>	*
1741	>	* <p>A {@code ManagedBlocker} provides two methods.
1742	>	* Method {@code isReleasable} must return {@code true} if
1743	>	* blocking is not necessary. Method {@code block} blocks the
1744	>	* current thread if necessary (perhaps internally invoking
1745	>	* {@code isReleasable} before actually blocking.).
1746	>	*
1747		* <p>For example, here is a ManagedBlocker based on a
1748		* ReentrantLock:
1749	<	* <pre>
1750	<	*   class ManagedLocker implements ManagedBlocker {
1751	<	*     final ReentrantLock lock;
1752	<	*     boolean hasLock = false;
1753	<	*     ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1754	<	*     public boolean block() {
1755	<	*        if (!hasLock)
1756	<	*           lock.lock();
1757	<	*        return true;
1711	<	*     }
1712	<	*     public boolean isReleasable() {
1713	<	*        return hasLock || (hasLock = lock.tryLock());
1714	<	*     }
1749	>	*  <pre> {@code
1750	>	* class ManagedLocker implements ManagedBlocker {
1751	>	*   final ReentrantLock lock;
1752	>	*   boolean hasLock = false;
1753	>	*   ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1754	>	*   public boolean block() {
1755	>	*     if (!hasLock)
1756	>	*       lock.lock();
1757	>	*     return true;
1758		*   }
1759	<	* </pre>
1759	>	*   public boolean isReleasable() {
1760	>	*     return hasLock || (hasLock = lock.tryLock());
1761	>	*   }
1762	>	* }}</pre>
1763		*/
1764		public static interface ManagedBlocker {
1765		/**
1766		* Possibly blocks the current thread, for example waiting for
1767		* a lock or condition.
1768	<	* @return true if no additional blocking is necessary (i.e.,
1769	<	* if isReleasable would return true)
1768	>	*
1769	>	* @return {@code true} if no additional blocking is necessary
1770	>	* (i.e., if isReleasable would return true)
1771		* @throws InterruptedException if interrupted while waiting
1772	<	* (the method is not required to do so, but is allowed to).
1772	>	* (the method is not required to do so, but is allowed to)
1773		*/
1774		boolean block() throws InterruptedException;
1775
1776		/**
1777	<	* Returns true if blocking is unnecessary.
1777	>	* Returns {@code true} if blocking is unnecessary.
1778		*/
1779		boolean isReleasable();
1780		}
1781
1782		/**
1783		* Blocks in accord with the given blocker.  If the current thread
1784	<	* is a ForkJoinWorkerThread, this method possibly arranges for a
1785	<	* spare thread to be activated if necessary to ensure parallelism
1786	<	* while the current thread is blocked.  If
1787	<	* {@code maintainParallelism} is true and the pool supports
1788	<	* it ({@link #getMaintainsParallelism}), this method attempts to
1789	<	* maintain the pool's nominal parallelism. Otherwise if activates
1790	<	* a thread only if necessary to avoid complete starvation. This
1791	<	* option may be preferable when blockages use timeouts, or are
1792	<	* almost always brief.
1793	<	*
1794	<	* <p> If the caller is not a ForkJoinTask, this method is behaviorally
1795	<	* equivalent to
1796	<	* <pre>
1797	<	*   while (!blocker.isReleasable())
1798	<	*      if (blocker.block())
1799	<	*         return;
1800	<	* </pre>
1801	<	* If the caller is a ForkJoinTask, then the pool may first
1802	<	* be expanded to ensure parallelism, and later adjusted.
1784	>	* is a {@link ForkJoinWorkerThread}, this method possibly
1785	>	* arranges for a spare thread to be activated if necessary to
1786	>	* ensure parallelism while the current thread is blocked.
1787	>	*
1788	>	* <p>If {@code maintainParallelism} is {@code true} and the pool
1789	>	* supports it ({@link #getMaintainsParallelism}), this method
1790	>	* attempts to maintain the pool's nominal parallelism. Otherwise
1791	>	* it activates a thread only if necessary to avoid complete
1792	>	* starvation. This option may be preferable when blockages use
1793	>	* timeouts, or are almost always brief.
1794	>	*
1795	>	* <p>If the caller is not a {@link ForkJoinTask}, this method is
1796	>	* behaviorally equivalent to
1797	>	*  <pre> {@code
1798	>	* while (!blocker.isReleasable())
1799	>	*   if (blocker.block())
1800	>	*     return;
1801	>	* }</pre>
1802	>	*
1803	>	* If the caller is a {@code ForkJoinTask}, then the pool may
1804	>	* first be expanded to ensure parallelism, and later adjusted.
1805		*
1806		* @param blocker the blocker
1807	<	* @param maintainParallelism if true and supported by this pool,
1808	<	* attempt to maintain the pool's nominal parallelism; otherwise
1809	<	* activate a thread only if necessary to avoid complete
1810	<	* starvation.
1807	>	* @param maintainParallelism if {@code true} and supported by
1808	>	* this pool, attempt to maintain the pool's nominal parallelism;
1809	>	* otherwise activate a thread only if necessary to avoid
1810	>	* complete starvation.
1811		* @throws InterruptedException if blocker.block did so
1812		*/
1813		public static void managedBlock(ManagedBlocker blocker,
1814		boolean maintainParallelism)
1815		throws InterruptedException {
1816		Thread t = Thread.currentThread();
1817	<	ForkJoinPool pool = (t instanceof ForkJoinWorkerThread?
1818	<	((ForkJoinWorkerThread)t).pool : null);
1817	>	ForkJoinPool pool = ((t instanceof ForkJoinWorkerThread) ?
1818	>	((ForkJoinWorkerThread) t).pool : null);
1819		if (!blocker.isReleasable()) {
1820		try {
1821		if (pool == null ||
#	Line 1781 | Line 1830 | public class ForkJoinPool extends Abstra
1830
1831		private static void awaitBlocker(ManagedBlocker blocker)
1832		throws InterruptedException {
1833	<	do;while (!blocker.isReleasable() && !blocker.block());
1833	>	do {} while (!blocker.isReleasable() && !blocker.block());
1834		}
1835
1836	<	// AbstractExecutorService overrides
1836	>	// AbstractExecutorService overrides.  These rely on undocumented
1837	>	// fact that ForkJoinTask.adapt returns ForkJoinTasks that also
1838	>	// implement RunnableFuture.
1839
1840		protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
1841	<	return new AdaptedRunnable(runnable, value);
1841	>	return (RunnableFuture<T>) ForkJoinTask.adapt(runnable, value);
1842		}
1843
1844		protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
1845	<	return new AdaptedCallable(callable);
1845	>	return (RunnableFuture<T>) ForkJoinTask.adapt(callable);
1846		}
1847
1848	+	// Unsafe mechanics
1849
1850	<	// Temporary Unsafe mechanics for preliminary release
1851	<	private static Unsafe getUnsafe() throws Throwable {
1852	<	try {
1853	<	return Unsafe.getUnsafe();
1854	<	} catch (SecurityException se) {
1855	<	try {
1856	<	return java.security.AccessController.doPrivileged
1857	<	(new java.security.PrivilegedExceptionAction<Unsafe>() {
1858	<	public Unsafe run() throws Exception {
1859	<	return getUnsafePrivileged();
1860	<	}});
1809	<	} catch (java.security.PrivilegedActionException e) {
1810	<	throw e.getCause();
1811	<	}
1812	<	}
1813	<	}
1814	<
1815	<	private static Unsafe getUnsafePrivileged()
1816	<	throws NoSuchFieldException, IllegalAccessException {
1817	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1818	<	f.setAccessible(true);
1819	<	return (Unsafe) f.get(null);
1820	<	}
1821	<
1822	<	private static long fieldOffset(String fieldName)
1823	<	throws NoSuchFieldException {
1824	<	return UNSAFE.objectFieldOffset
1825	<	(ForkJoinPool.class.getDeclaredField(fieldName));
1826	<	}
1827	<
1828	<	static final Unsafe UNSAFE;
1829	<	static final long eventCountOffset;
1830	<	static final long workerCountsOffset;
1831	<	static final long runControlOffset;
1832	<	static final long syncStackOffset;
1833	<	static final long spareStackOffset;
1834	<
1835	<	static {
1836	<	try {
1837	<	UNSAFE = getUnsafe();
1838	<	eventCountOffset = fieldOffset("eventCount");
1839	<	workerCountsOffset = fieldOffset("workerCounts");
1840	<	runControlOffset = fieldOffset("runControl");
1841	<	syncStackOffset = fieldOffset("syncStack");
1842	<	spareStackOffset = fieldOffset("spareStack");
1843	<	} catch (Throwable e) {
1844	<	throw new RuntimeException("Could not initialize intrinsics", e);
1845	<	}
1846	<	}
1850	>	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1851	>	private static final long eventCountOffset =
1852	>	objectFieldOffset("eventCount", ForkJoinPool.class);
1853	>	private static final long workerCountsOffset =
1854	>	objectFieldOffset("workerCounts", ForkJoinPool.class);
1855	>	private static final long runControlOffset =
1856	>	objectFieldOffset("runControl", ForkJoinPool.class);
1857	>	private static final long syncStackOffset =
1858	>	objectFieldOffset("syncStack",ForkJoinPool.class);
1859	>	private static final long spareStackOffset =
1860	>	objectFieldOffset("spareStack", ForkJoinPool.class);
1861
1862		private boolean casEventCount(long cmp, long val) {
1863		return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val);
#	Line 1860 | Line 1874 | public class ForkJoinPool extends Abstra
1874		private boolean casBarrierStack(WaitQueueNode cmp, WaitQueueNode val) {
1875		return UNSAFE.compareAndSwapObject(this, syncStackOffset, cmp, val);
1876		}
1877	+
1878	+	private static long objectFieldOffset(String field, Class<?> klazz) {
1879	+	try {
1880	+	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
1881	+	} catch (NoSuchFieldException e) {
1882	+	// Convert Exception to corresponding Error
1883	+	NoSuchFieldError error = new NoSuchFieldError(field);
1884	+	error.initCause(e);
1885	+	throw error;
1886	+	}
1887	+	}
1888	+
1889	+	/**
1890	+	* Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
1891	+	* Replace with a simple call to Unsafe.getUnsafe when integrating
1892	+	* into a jdk.
1893	+	*
1894	+	* @return a sun.misc.Unsafe
1895	+	*/
1896	+	private static sun.misc.Unsafe getUnsafe() {
1897	+	try {
1898	+	return sun.misc.Unsafe.getUnsafe();
1899	+	} catch (SecurityException se) {
1900	+	try {
1901	+	return java.security.AccessController.doPrivileged
1902	+	(new java.security
1903	+	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1904	+	public sun.misc.Unsafe run() throws Exception {
1905	+	java.lang.reflect.Field f = sun.misc
1906	+	.Unsafe.class.getDeclaredField("theUnsafe");
1907	+	f.setAccessible(true);
1908	+	return (sun.misc.Unsafe) f.get(null);
1909	+	}});
1910	+	} catch (java.security.PrivilegedActionException e) {
1911	+	throw new RuntimeException("Could not initialize intrinsics",
1912	+	e.getCause());
1913	+	}
1914	+	}
1915	+	}
1916		}

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