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

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.16 by jsr166, Thu Jul 23 19:44:46 2009 UTC vs.
Revision 1.20 by jsr166, Fri Jul 24 22:05:22 2009 UTC

#	Line 90 | Line 90 | public class ForkJoinPool extends Abstra
90		}
91
92		/**
93	<	* Default ForkJoinWorkerThreadFactory implementation, creates a
93	>	* Default ForkJoinWorkerThreadFactory implementation; creates a
94		* new ForkJoinWorkerThread.
95		*/
96		static class  DefaultForkJoinWorkerThreadFactory
#	Line 184 | Line 184 | public class ForkJoinPool extends Abstra
184		private final LinkedTransferQueue<ForkJoinTask<?>> submissionQueue;
185
186		/**
187	<	* Head of Treiber stack for barrier sync. See below for explanation
187	>	* Head of Treiber stack for barrier sync. See below for explanation.
188		*/
189		private volatile WaitQueueNode syncStack;
190
#	Line 232 | Line 232 | public class ForkJoinPool extends Abstra
232		* Adds delta (which may be negative) to running count.  This must
233		* be called before (with negative arg) and after (with positive)
234		* any managed synchronization (i.e., mainly, joins).
235	+	*
236		* @param delta the number to add
237		*/
238		final void updateRunningCount(int delta) {
239		int s;
240	<	do;while (!casWorkerCounts(s = workerCounts, s + delta));
240	>	do {} while (!casWorkerCounts(s = workerCounts, s + delta));
241		}
242
243		/**
244		* Adds delta (which may be negative) to both total and running
245		* count.  This must be called upon creation and termination of
246		* worker threads.
247	+	*
248		* @param delta the number to add
249		*/
250		private void updateWorkerCount(int delta) {
251		int d = delta + (delta << 16); // add to both lo and hi parts
252		int s;
253	<	do;while (!casWorkerCounts(s = workerCounts, s + d));
253	>	do {} while (!casWorkerCounts(s = workerCounts, s + d));
254		}
255
256		/**
#	Line 274 | Line 276 | public class ForkJoinPool extends Abstra
276		private static int runControlFor(int r, int a)   { return (r << 16) + a; }
277
278		/**
279	<	* Try incrementing active count; fail on contention. Called by
280	<	* workers before/during executing tasks.
279	>	* Tries incrementing active count; fails on contention.
280	>	* Called by workers before/during executing tasks.
281	>	*
282		* @return true on success
283		*/
284		final boolean tryIncrementActiveCount() {
#	Line 287 | Line 290 | public class ForkJoinPool extends Abstra
290		* Tries decrementing active count; fails on contention.
291		* Possibly triggers termination on success.
292		* Called by workers when they can't find tasks.
293	+	*
294		* @return true on success
295		*/
296		final boolean tryDecrementActiveCount() {
#	Line 305 | Line 309 | public class ForkJoinPool extends Abstra
309		* terminating on shutdown.
310		*/
311		private static boolean canTerminateOnShutdown(int c) {
312	<	return ((c & -c) >>> 16) != 0; // i.e. least bit is nonzero runState bit
312	>	// i.e. least bit is nonzero runState bit
313	>	return ((c & -c) >>> 16) != 0;
314		}
315
316		/**
#	Line 331 | Line 336 | public class ForkJoinPool extends Abstra
336
337		/**
338		* Creates a ForkJoinPool with a pool size equal to the number of
339	<	* processors available on the system and using the default
340	<	* ForkJoinWorkerThreadFactory,
339	>	* processors available on the system, using the default
340	>	* ForkJoinWorkerThreadFactory.
341	>	*
342		* @throws SecurityException if a security manager exists and
343		*         the caller is not permitted to modify threads
344		*         because it does not hold {@link
345	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
345	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
346		*/
347		public ForkJoinPool() {
348		this(Runtime.getRuntime().availableProcessors(),
#	Line 345 | Line 351 | public class ForkJoinPool extends Abstra
351
352		/**
353		* Creates a ForkJoinPool with the indicated parallelism level
354	<	* threads, and using the default ForkJoinWorkerThreadFactory,
354	>	* threads and using the default ForkJoinWorkerThreadFactory.
355	>	*
356		* @param parallelism the number of worker threads
357		* @throws IllegalArgumentException if parallelism less than or
358		* equal to zero
359		* @throws SecurityException if a security manager exists and
360		*         the caller is not permitted to modify threads
361		*         because it does not hold {@link
362	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
362	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
363		*/
364		public ForkJoinPool(int parallelism) {
365		this(parallelism, defaultForkJoinWorkerThreadFactory);
#	Line 361 | Line 368 | public class ForkJoinPool extends Abstra
368		/**
369		* Creates a ForkJoinPool with parallelism equal to the number of
370		* processors available on the system and using the given
371	<	* ForkJoinWorkerThreadFactory,
371	>	* ForkJoinWorkerThreadFactory.
372	>	*
373		* @param factory the factory for creating new threads
374		* @throws NullPointerException if factory is null
375		* @throws SecurityException if a security manager exists and
376		*         the caller is not permitted to modify threads
377		*         because it does not hold {@link
378	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
378	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
379		*/
380		public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
381		this(Runtime.getRuntime().availableProcessors(), factory);
#	Line 384 | Line 392 | public class ForkJoinPool extends Abstra
392		* @throws SecurityException if a security manager exists and
393		*         the caller is not permitted to modify threads
394		*         because it does not hold {@link
395	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
395	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
396		*/
397		public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
398		if (parallelism <= 0 || parallelism > MAX_THREADS)
#	Line 405 | Line 413 | public class ForkJoinPool extends Abstra
413		}
414
415		/**
416	<	* Create new worker using factory.
416	>	* Creates a new worker thread using factory.
417	>	*
418		* @param index the index to assign worker
419		* @return new worker, or null of factory failed
420		*/
#	Line 427 | Line 436 | public class ForkJoinPool extends Abstra
436		* Returns a good size for worker array given pool size.
437		* Currently requires size to be a power of two.
438		*/
439	<	private static int arraySizeFor(int ps) {
440	<	return ps <= 1? 1 : (1 << (32 - Integer.numberOfLeadingZeros(ps-1)));
439	>	private static int arraySizeFor(int poolSize) {
440	>	return (poolSize <= 1) ? 1 :
441	>	(1 << (32 - Integer.numberOfLeadingZeros(poolSize-1)));
442		}
443
444		/**
#	Line 448 | Line 458 | public class ForkJoinPool extends Abstra
458		}
459
460		/**
461	<	* Try to shrink workers into smaller array after one or more terminate
461	>	* Tries to shrink workers into smaller array after one or more terminate.
462		*/
463		private void tryShrinkWorkerArray() {
464		ForkJoinWorkerThread[] ws = workers;
#	Line 464 | Line 474 | public class ForkJoinPool extends Abstra
474		}
475
476		/**
477	<	* Initialize workers if necessary
477	>	* Initializes workers if necessary.
478		*/
479		final void ensureWorkerInitialization() {
480		ForkJoinWorkerThread[] ws = workers;
#	Line 540 | Line 550 | public class ForkJoinPool extends Abstra
550		}
551
552		/**
553	<	* Performs the given task; returning its result upon completion
553	>	* Performs the given task, returning its result upon completion.
554	>	*
555		* @param task the task
556		* @return the task's result
557		* @throws NullPointerException if task is null
#	Line 553 | Line 564 | public class ForkJoinPool extends Abstra
564
565		/**
566		* Arranges for (asynchronous) execution of the given task.
567	+	*
568		* @param task the task
569		* @throws NullPointerException if task is null
570		* @throws RejectedExecutionException if pool is shut down
#	Line 587 | Line 599 | public class ForkJoinPool extends Abstra
599
600		/**
601		* Adaptor for Runnables. This implements RunnableFuture
602	<	* to be compliant with AbstractExecutorService constraints
602	>	* to be compliant with AbstractExecutorService constraints.
603		*/
604		static final class AdaptedRunnable<T> extends ForkJoinTask<T>
605		implements RunnableFuture<T> {
#	Line 607 | Line 619 | public class ForkJoinPool extends Abstra
619		return true;
620		}
621		public void run() { invoke(); }
622	+	private static final long serialVersionUID = 5232453952276885070L;
623		}
624
625		/**
#	Line 635 | Line 648 | public class ForkJoinPool extends Abstra
648		}
649		}
650		public void run() { invoke(); }
651	+	private static final long serialVersionUID = 2838392045355241008L;
652		}
653
654		public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
655	<	ArrayList<ForkJoinTask<T>> ts =
655	>	ArrayList<ForkJoinTask<T>> forkJoinTasks =
656		new ArrayList<ForkJoinTask<T>>(tasks.size());
657	<	for (Callable<T> c : tasks)
658	<	ts.add(new AdaptedCallable<T>(c));
659	<	invoke(new InvokeAll<T>(ts));
660	<	return (List<Future<T>>)(List)ts;
657	>	for (Callable<T> task : tasks)
658	>	forkJoinTasks.add(new AdaptedCallable<T>(task));
659	>	invoke(new InvokeAll<T>(forkJoinTasks));
660	>
661	>	@SuppressWarnings({"unchecked", "rawtypes"})
662	>	List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks;
663	>	return futures;
664		}
665
666		static final class InvokeAll<T> extends RecursiveAction {
667		final ArrayList<ForkJoinTask<T>> tasks;
668		InvokeAll(ArrayList<ForkJoinTask<T>> tasks) { this.tasks = tasks; }
669		public void compute() {
670	<	try { invokeAll(tasks); } catch(Exception ignore) {}
670	>	try { invokeAll(tasks); }
671	>	catch (Exception ignore) {}
672		}
673	+	private static final long serialVersionUID = -7914297376763021607L;
674		}
675
676		// Configuration and status settings and queries
677
678		/**
679	<	* Returns the factory used for constructing new workers
679	>	* Returns the factory used for constructing new workers.
680		*
681		* @return the factory used for constructing new workers
682		*/
#	Line 668 | Line 687 | public class ForkJoinPool extends Abstra
687		/**
688		* Returns the handler for internal worker threads that terminate
689		* due to unrecoverable errors encountered while executing tasks.
690	+	*
691		* @return the handler, or null if none
692		*/
693		public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
#	Line 693 | Line 713 | public class ForkJoinPool extends Abstra
713		* @throws SecurityException if a security manager exists and
714		*         the caller is not permitted to modify threads
715		*         because it does not hold {@link
716	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
716	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
717		*/
718		public Thread.UncaughtExceptionHandler
719		setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
#	Line 721 | Line 741 | public class ForkJoinPool extends Abstra
741
742		/**
743		* Sets the target parallelism level of this pool.
744	+	*
745		* @param parallelism the target parallelism
746		* @throws IllegalArgumentException if parallelism less than or
747		* equal to zero or greater than maximum size bounds
748		* @throws SecurityException if a security manager exists and
749		*         the caller is not permitted to modify threads
750		*         because it does not hold {@link
751	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
751	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
752		*/
753		public void setParallelism(int parallelism) {
754		checkPermission();
#	Line 774 | Line 795 | public class ForkJoinPool extends Abstra
795		/**
796		* Returns the maximum number of threads allowed to exist in the
797		* pool, even if there are insufficient unblocked running threads.
798	+	*
799		* @return the maximum
800		*/
801		public int getMaximumPoolSize() {
#	Line 785 | Line 807 | public class ForkJoinPool extends Abstra
807		* pool, even if there are insufficient unblocked running threads.
808		* Setting this value has no effect on current pool size. It
809		* controls construction of new threads.
810	+	*
811		* @throws IllegalArgumentException if negative or greater then
812		* internal implementation limit
813		*/
#	Line 799 | Line 822 | public class ForkJoinPool extends Abstra
822		* Returns true if this pool dynamically maintains its target
823		* parallelism level. If false, new threads are added only to
824		* avoid possible starvation.
825	<	* This setting is by default true;
825	>	* This setting is by default true.
826	>	*
827		* @return true if maintains parallelism
828		*/
829		public boolean getMaintainsParallelism() {
#	Line 810 | Line 834 | public class ForkJoinPool extends Abstra
834		* Sets whether this pool dynamically maintains its target
835		* parallelism level. If false, new threads are added only to
836		* avoid possible starvation.
837	+	*
838		* @param enable true to maintains parallelism
839		*/
840		public void setMaintainsParallelism(boolean enable) {
#	Line 867 | Line 892 | public class ForkJoinPool extends Abstra
892		* Returns an estimate of the number of threads that are currently
893		* stealing or executing tasks. This method may overestimate the
894		* number of active threads.
895	+	*
896		* @return the number of active threads
897		*/
898		public int getActiveThreadCount() {
#	Line 877 | Line 903 | public class ForkJoinPool extends Abstra
903		* Returns an estimate of the number of threads that are currently
904		* idle waiting for tasks. This method may underestimate the
905		* number of idle threads.
906	+	*
907		* @return the number of idle threads
908		*/
909		final int getIdleThreadCount() {
910		int c = runningCountOf(workerCounts) - activeCountOf(runControl);
911	<	return (c <= 0)? 0 : c;
911	>	return (c <= 0) ? 0 : c;
912		}
913
914		/**
915		* Returns true if all worker threads are currently idle. An idle
916		* worker is one that cannot obtain a task to execute because none
917		* are available to steal from other threads, and there are no
918	<	* pending submissions to the pool. This method is conservative:
919	<	* It might not return true immediately upon idleness of all
918	>	* pending submissions to the pool. This method is conservative;
919	>	* it might not return true immediately upon idleness of all
920		* threads, but will eventually become true if threads remain
921		* inactive.
922	+	*
923		* @return true if all threads are currently idle
924		*/
925		public boolean isQuiescent() {
#	Line 903 | Line 931 | public class ForkJoinPool extends Abstra
931		* one thread's work queue by another. The reported value
932		* underestimates the actual total number of steals when the pool
933		* is not quiescent. This value may be useful for monitoring and
934	<	* tuning fork/join programs: In general, steal counts should be
934	>	* tuning fork/join programs: in general, steal counts should be
935		* high enough to keep threads busy, but low enough to avoid
936		* overhead and contention across threads.
937	+	*
938		* @return the number of steals
939		*/
940		public long getStealCount() {
#	Line 913 | Line 942 | public class ForkJoinPool extends Abstra
942		}
943
944		/**
945	<	* Accumulate steal count from a worker. Call only
946	<	* when worker known to be idle.
945	>	* Accumulates steal count from a worker.
946	>	* Call only when worker known to be idle.
947		*/
948		private void updateStealCount(ForkJoinWorkerThread w) {
949		int sc = w.getAndClearStealCount();
#	Line 929 | Line 958 | public class ForkJoinPool extends Abstra
958		* an approximation, obtained by iterating across all threads in
959		* the pool. This method may be useful for tuning task
960		* granularities.
961	+	*
962		* @return the number of queued tasks
963		*/
964		public long getQueuedTaskCount() {
#	Line 948 | Line 978 | public class ForkJoinPool extends Abstra
978		* Returns an estimate of the number tasks submitted to this pool
979		* that have not yet begun executing. This method takes time
980		* proportional to the number of submissions.
981	+	*
982		* @return the number of queued submissions
983		*/
984		public int getQueuedSubmissionCount() {
#	Line 957 | Line 988 | public class ForkJoinPool extends Abstra
988		/**
989		* Returns true if there are any tasks submitted to this pool
990		* that have not yet begun executing.
991	+	*
992		* @return {@code true} if there are any queued submissions
993		*/
994		public boolean hasQueuedSubmissions() {
#	Line 967 | Line 999 | public class ForkJoinPool extends Abstra
999		* Removes and returns the next unexecuted submission if one is
1000		* available.  This method may be useful in extensions to this
1001		* class that re-assign work in systems with multiple pools.
1002	+	*
1003		* @return the next submission, or null if none
1004		*/
1005		protected ForkJoinTask<?> pollSubmission() {
#	Line 986 | Line 1019 | public class ForkJoinPool extends Abstra
1019		* exception is thrown.  The behavior of this operation is
1020		* undefined if the specified collection is modified while the
1021		* operation is in progress.
1022	+	*
1023		* @param c the collection to transfer elements into
1024		* @return the number of elements transferred
1025		*/
#	Line 1046 | Line 1080 | public class ForkJoinPool extends Abstra
1080		* Invocation has no additional effect if already shut down.
1081		* Tasks that are in the process of being submitted concurrently
1082		* during the course of this method may or may not be rejected.
1083	+	*
1084		* @throws SecurityException if a security manager exists and
1085		*         the caller is not permitted to modify threads
1086		*         because it does not hold {@link
1087	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1087	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1088		*/
1089		public void shutdown() {
1090		checkPermission();
#	Line 1067 | Line 1102 | public class ForkJoinPool extends Abstra
1102		* upon termination, so always returns an empty list. However, you
1103		* can use method {@code drainTasksTo} before invoking this
1104		* method to transfer unexecuted tasks to another collection.
1105	+	*
1106		* @return an empty list
1107		* @throws SecurityException if a security manager exists and
1108		*         the caller is not permitted to modify threads
1109		*         because it does not hold {@link
1110	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1110	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1111		*/
1112		public List<Runnable> shutdownNow() {
1113		checkPermission();
#	Line 1139 | Line 1175 | public class ForkJoinPool extends Abstra
1175		// Shutdown and termination support
1176
1177		/**
1178	<	* Callback from terminating worker. Null out the corresponding
1179	<	* workers slot, and if terminating, try to terminate, else try to
1180	<	* shrink workers array.
1178	>	* Callback from terminating worker. Nulls out the corresponding
1179	>	* workers slot, and if terminating, tries to terminate; else
1180	>	* tries to shrink workers array.
1181	>	*
1182		* @param w the worker
1183		*/
1184		final void workerTerminated(ForkJoinWorkerThread w) {
#	Line 1172 | Line 1209 | public class ForkJoinPool extends Abstra
1209		}
1210
1211		/**
1212	<	* Initiate termination.
1212	>	* Initiates termination.
1213		*/
1214		private void terminate() {
1215		if (transitionRunStateTo(TERMINATING)) {
#	Line 1349 | Line 1386 | public class ForkJoinPool extends Abstra
1386		* Ensures that no thread is waiting for count to advance from the
1387		* current value of eventCount read on entry to this method, by
1388		* releasing waiting threads if necessary.
1389	+	*
1390		* @return the count
1391		*/
1392		final long ensureSync() {
#	Line 1370 | Line 1408 | public class ForkJoinPool extends Abstra
1408		*/
1409		private void signalIdleWorkers() {
1410		long c;
1411	<	do;while (!casEventCount(c = eventCount, c+1));
1411	>	do {} while (!casEventCount(c = eventCount, c+1));
1412		ensureSync();
1413		}
1414
#	Line 1394 | Line 1432 | public class ForkJoinPool extends Abstra
1432		* Waits until event count advances from last value held by
1433		* caller, or if excess threads, caller is resumed as spare, or
1434		* caller or pool is terminating. Updates caller's event on exit.
1435	+	*
1436		* @param w the calling worker thread
1437		*/
1438		final void sync(ForkJoinWorkerThread w) {
#	Line 1424 | Line 1463 | public class ForkJoinPool extends Abstra
1463		* Returns true if worker waiting on sync can proceed:
1464		*  - on signal (thread == null)
1465		*  - on event count advance (winning race to notify vs signaller)
1466	<	*  - on Interrupt
1466	>	*  - on interrupt
1467		*  - if the first queued node, we find work available
1468		* If node was not signalled and event count not advanced on exit,
1469		* then we also help advance event count.
1470	+	*
1471		* @return true if node can be released
1472		*/
1473		final boolean syncIsReleasable(WaitQueueNode node) {
#	Line 1468 | Line 1508 | public class ForkJoinPool extends Abstra
1508		* spare thread when one is about to block (and remove or
1509		* suspend it later when unblocked -- see suspendIfSpare).
1510		* However, implementing this idea requires coping with
1511	<	* several problems: We have imperfect information about the
1511	>	* several problems: we have imperfect information about the
1512		* states of threads. Some count updates can and usually do
1513		* lag run state changes, despite arrangements to keep them
1514		* accurate (for example, when possible, updating counts
#	Line 1491 | Line 1531 | public class ForkJoinPool extends Abstra
1531		* target counts, else create only to avoid starvation
1532		* @return true if joinMe known to be done
1533		*/
1534	<	final boolean preJoin(ForkJoinTask<?> joinMe, boolean maintainParallelism) {
1534	>	final boolean preJoin(ForkJoinTask<?> joinMe,
1535	>	boolean maintainParallelism) {
1536		maintainParallelism &= maintainsParallelism; // overrride
1537		boolean dec = false;  // true when running count decremented
1538		while (spareStack == null || !tryResumeSpare(dec)) {
1539		int counts = workerCounts;
1540	<	if (dec || (dec = casWorkerCounts(counts, --counts))) { // CAS cheat
1540	>	if (dec || (dec = casWorkerCounts(counts, --counts))) {
1541	>	// CAS cheat
1542		if (!needSpare(counts, maintainParallelism))
1543		break;
1544		if (joinMe.status < 0)
#	Line 1511 | Line 1553 | public class ForkJoinPool extends Abstra
1553		/**
1554		* Same idea as preJoin
1555		*/
1556	<	final boolean preBlock(ManagedBlocker blocker, boolean maintainParallelism){
1556	>	final boolean preBlock(ManagedBlocker blocker,
1557	>	boolean maintainParallelism) {
1558		maintainParallelism &= maintainsParallelism;
1559		boolean dec = false;
1560		while (spareStack == null || !tryResumeSpare(dec)) {
#	Line 1535 | Line 1578 | public class ForkJoinPool extends Abstra
1578		* there is apparently some work to do.  This self-limiting rule
1579		* means that the more threads that have already been added, the
1580		* less parallelism we will tolerate before adding another.
1581	+	*
1582		* @param counts current worker counts
1583		* @param maintainParallelism try to maintain parallelism
1584		*/
#	Line 1554 | Line 1598 | public class ForkJoinPool extends Abstra
1598		/**
1599		* Adds a spare worker if lock available and no more than the
1600		* expected numbers of threads exist.
1601	+	*
1602		* @return true if successful
1603		*/
1604		private boolean tryAddSpare(int expectedCounts) {
#	Line 1613 | Line 1658 | public class ForkJoinPool extends Abstra
1658		* the same WaitQueueNodes as barriers.  They are resumed mainly
1659		* in preJoin, but are also woken on pool events that require all
1660		* threads to check run state.
1661	+	*
1662		* @param w the caller
1663		*/
1664		private boolean suspendIfSpare(ForkJoinWorkerThread w) {
#	Line 1623 | Line 1669 | public class ForkJoinPool extends Abstra
1669		node = new WaitQueueNode(0, w);
1670		if (casWorkerCounts(s, s-1)) { // representation-dependent
1671		// push onto stack
1672	<	do;while (!casSpareStack(node.next = spareStack, node));
1672	>	do {} while (!casSpareStack(node.next = spareStack, node));
1673		// block until released by resumeSpare
1674		node.awaitSpareRelease();
1675		return true;
#	Line 1634 | Line 1680 | public class ForkJoinPool extends Abstra
1680
1681		/**
1682		* Tries to pop and resume a spare thread.
1683	+	*
1684		* @param updateCount if true, increment running count on success
1685		* @return true if successful
1686		*/
#	Line 1652 | Line 1699 | public class ForkJoinPool extends Abstra
1699
1700		/**
1701		* Pops and resumes all spare threads. Same idea as ensureSync.
1702	+	*
1703		* @return true if any spares released
1704		*/
1705		private boolean resumeAllSpares() {
#	Line 1695 | Line 1743 | public class ForkJoinPool extends Abstra
1743		* Interface for extending managed parallelism for tasks running
1744		* in ForkJoinPools. A ManagedBlocker provides two methods.
1745		* Method {@code isReleasable} must return true if blocking is not
1746	<	* necessary. Method {@code block} blocks the current thread
1747	<	* if necessary (perhaps internally invoking isReleasable before
1748	<	* actually blocking.).
1746	>	* necessary. Method {@code block} blocks the current thread if
1747	>	* necessary (perhaps internally invoking {@code isReleasable}
1748	>	* before actually blocking.).
1749	>	*
1750		* <p>For example, here is a ManagedBlocker based on a
1751		* ReentrantLock:
1752	<	* <pre>
1753	<	*   class ManagedLocker implements ManagedBlocker {
1754	<	*     final ReentrantLock lock;
1755	<	*     boolean hasLock = false;
1756	<	*     ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1757	<	*     public boolean block() {
1758	<	*        if (!hasLock)
1759	<	*           lock.lock();
1760	<	*        return true;
1761	<	*     }
1762	<	*     public boolean isReleasable() {
1763	<	*        return hasLock || (hasLock = lock.tryLock());
1715	<	*     }
1752	>	*  <pre> {@code
1753	>	* class ManagedLocker implements ManagedBlocker {
1754	>	*   final ReentrantLock lock;
1755	>	*   boolean hasLock = false;
1756	>	*   ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1757	>	*   public boolean block() {
1758	>	*     if (!hasLock)
1759	>	*       lock.lock();
1760	>	*     return true;
1761	>	*   }
1762	>	*   public boolean isReleasable() {
1763	>	*     return hasLock || (hasLock = lock.tryLock());
1764		*   }
1765	<	* </pre>
1765	>	* }}</pre>
1766		*/
1767		public static interface ManagedBlocker {
1768		/**
1769		* Possibly blocks the current thread, for example waiting for
1770		* a lock or condition.
1771	+	*
1772		* @return true if no additional blocking is necessary (i.e.,
1773		* if isReleasable would return true)
1774		* @throws InterruptedException if interrupted while waiting
1775	<	* (the method is not required to do so, but is allowed to).
1775	>	* (the method is not required to do so, but is allowed to)
1776		*/
1777		boolean block() throws InterruptedException;
1778
#	Line 1740 | Line 1789 | public class ForkJoinPool extends Abstra
1789		* while the current thread is blocked.  If
1790		* {@code maintainParallelism} is true and the pool supports
1791		* it ({@link #getMaintainsParallelism}), this method attempts to
1792	<	* maintain the pool's nominal parallelism. Otherwise if activates
1792	>	* maintain the pool's nominal parallelism. Otherwise it activates
1793		* a thread only if necessary to avoid complete starvation. This
1794		* option may be preferable when blockages use timeouts, or are
1795		* almost always brief.
1796		*
1797		* <p> If the caller is not a ForkJoinTask, this method is behaviorally
1798		* equivalent to
1799	<	* <pre>
1800	<	*   while (!blocker.isReleasable())
1801	<	*      if (blocker.block())
1802	<	*         return;
1803	<	* </pre>
1799	>	*  <pre> {@code
1800	>	* while (!blocker.isReleasable())
1801	>	*   if (blocker.block())
1802	>	*     return;
1803	>	* }</pre>
1804		* If the caller is a ForkJoinTask, then the pool may first
1805		* be expanded to ensure parallelism, and later adjusted.
1806		*
#	Line 1766 | Line 1815 | public class ForkJoinPool extends Abstra
1815		boolean maintainParallelism)
1816		throws InterruptedException {
1817		Thread t = Thread.currentThread();
1818	<	ForkJoinPool pool = (t instanceof ForkJoinWorkerThread?
1819	<	((ForkJoinWorkerThread)t).pool : null);
1818	>	ForkJoinPool pool = ((t instanceof ForkJoinWorkerThread) ?
1819	>	((ForkJoinWorkerThread) t).pool : null);
1820		if (!blocker.isReleasable()) {
1821		try {
1822		if (pool == null ||
#	Line 1782 | Line 1831 | public class ForkJoinPool extends Abstra
1831
1832		private static void awaitBlocker(ManagedBlocker blocker)
1833		throws InterruptedException {
1834	<	do;while (!blocker.isReleasable() && !blocker.block());
1834	>	do {} while (!blocker.isReleasable() && !blocker.block());
1835		}
1836
1837		// AbstractExecutorService overrides
1838
1839		protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
1840	<	return new AdaptedRunnable(runnable, value);
1840	>	return new AdaptedRunnable<T>(runnable, value);
1841		}
1842
1843		protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
1844	<	return new AdaptedCallable(callable);
1844	>	return new AdaptedCallable<T>(callable);
1845		}
1846
1847

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