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root/jsr166/jsr166/src/jsr166y/ForkJoinTask.java

Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.12 by jsr166, Wed Jul 22 01:36:51 2009 UTC vs.
Revision 1.14 by jsr166, Thu Jul 23 23:07:57 2009 UTC

#	Line 81 | Line 81 | import java.lang.reflect.*;
81		* class. While these methods have {@code public} access (to allow
82		* instances of different task subclasses to call each others
83		* methods), some of them may only be called from within other
84	<	* ForkJoinTasks. Attempts to invoke them in other contexts result in
85	<	* exceptions or errors possibly including ClassCastException.
84	>	* ForkJoinTasks (as may be determined using method {@link
85	>	* #inForkJoinPool}).  Attempts to invoke them in other contexts
86	>	* result in exceptions or errors, possibly including
87	>	* ClassCastException.
88		*
89		* <p>Most base support methods are {@code final} because their
90		* implementations are intrinsically tied to the underlying
#	Line 160 | Line 162 | public abstract class ForkJoinTask<V> im
162		*/
163		static ForkJoinWorkerThread getWorker() {
164		Thread t = Thread.currentThread();
165	<	return ((t instanceof ForkJoinWorkerThread)?
166	<	(ForkJoinWorkerThread)t : null);
165	>	return ((t instanceof ForkJoinWorkerThread) ?
166	>	(ForkJoinWorkerThread) t : null);
167		}
168
169		final boolean casStatus(int cmp, int val) {
#	Line 187 | Line 189 | public abstract class ForkJoinTask<V> im
189		ForkJoinPool pool = getPool();
190		if (pool != null) {
191		int s; // Clear signal bits while setting completion status
192	<	do;while ((s = status) >= 0 && !casStatus(s, completion));
192	>	do {} while ((s = status) >= 0 && !casStatus(s, completion));
193
194		if ((s & SIGNAL_MASK) != 0) {
195		if ((s &= INTERNAL_SIGNAL_MASK) != 0)
196		pool.updateRunningCount(s);
197	<	synchronized(this) { notifyAll(); }
197	>	synchronized (this) { notifyAll(); }
198		}
199		}
200		else
#	Line 205 | Line 207 | public abstract class ForkJoinTask<V> im
207		*/
208		private void externallySetCompletion(int completion) {
209		int s;
210	<	do;while ((s = status) >= 0 &&
211	<	!casStatus(s, (s & SIGNAL_MASK) | completion));
212	<	synchronized(this) { notifyAll(); }
210	>	do {} while ((s = status) >= 0 &&
211	>	!casStatus(s, (s & SIGNAL_MASK) | completion));
212	>	synchronized (this) { notifyAll(); }
213		}
214
215		/**
216	<	* Sets status to indicate normal completion
216	>	* Sets status to indicate normal completion.
217		*/
218		final void setNormalCompletion() {
219		// Try typical fast case -- single CAS, no signal, not already done.
#	Line 223 | Line 225 | public abstract class ForkJoinTask<V> im
225		// internal waiting and notification
226
227		/**
228	<	* Performs the actual monitor wait for awaitDone
228	>	* Performs the actual monitor wait for awaitDone.
229		*/
230		private void doAwaitDone() {
231		// Minimize lock bias and in/de-flation effects by maximizing
232		// chances of waiting inside sync
233		try {
234		while (status >= 0)
235	<	synchronized(this) { if (status >= 0) wait(); }
235	>	synchronized (this) { if (status >= 0) wait(); }
236		} catch (InterruptedException ie) {
237		onInterruptedWait();
238		}
239		}
240
241		/**
242	<	* Performs the actual monitor wait for awaitDone
242	>	* Performs the actual timed monitor wait for awaitDone.
243		*/
244		private void doAwaitDone(long startTime, long nanos) {
245	<	synchronized(this) {
245	>	synchronized (this) {
246		try {
247		while (status >= 0) {
248		long nt = nanos - System.nanoTime() - startTime;
249		if (nt <= 0)
250		break;
251	<	wait(nt / 1000000, (int)(nt % 1000000));
251	>	wait(nt / 1000000, (int) (nt % 1000000));
252		}
253		} catch (InterruptedException ie) {
254		onInterruptedWait();
#	Line 262 | Line 264 | public abstract class ForkJoinTask<V> im
264		*
265		* @return status upon exit
266		*/
267	<	private int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) {
268	<	ForkJoinPool pool = w == null? null : w.pool;
267	>	private int awaitDone(ForkJoinWorkerThread w,
268	>	boolean maintainParallelism) {
269	>	ForkJoinPool pool = (w == null) ? null : w.pool;
270		int s;
271		while ((s = status) >= 0) {
272	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
272	>	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
273		if (pool == null || !pool.preJoin(this, maintainParallelism))
274		doAwaitDone();
275		if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
#	Line 279 | Line 282 | public abstract class ForkJoinTask<V> im
282
283		/**
284		* Timed version of awaitDone
285	+	*
286		* @return status upon exit
287		*/
288		private int awaitDone(ForkJoinWorkerThread w, long nanos) {
289	<	ForkJoinPool pool = w == null? null : w.pool;
289	>	ForkJoinPool pool = (w == null) ? null : w.pool;
290		int s;
291		while ((s = status) >= 0) {
292	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
292	>	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
293		long startTime = System.nanoTime();
294		if (pool == null || !pool.preJoin(this, false))
295		doAwaitDone(startTime, nanos);
#	Line 307 | Line 311 | public abstract class ForkJoinTask<V> im
311		*/
312		private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
313		int s;
314	<	do;while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
314	>	do {} while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
315		if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
316		pool.updateRunningCount(s);
317		}
#	Line 362 | Line 366 | public abstract class ForkJoinTask<V> im
366
367		/**
368		* Returns result or throws exception using j.u.c.Future conventions.
369	<	* Only call when isDone known to be true.
369	>	* Only call when {@code isDone} known to be true.
370		*/
371		private V reportFutureResult()
372		throws ExecutionException, InterruptedException {
#	Line 428 | Line 432 | public abstract class ForkJoinTask<V> im
432		try {
433		if (!exec())
434		return;
435	<	} catch(Throwable rex) {
435	>	} catch (Throwable rex) {
436		setDoneExceptionally(rex);
437		return;
438		}
#	Line 460 | Line 464 | public abstract class ForkJoinTask<V> im
464		final void cancelIgnoringExceptions() {
465		try {
466		cancel(false);
467	<	} catch(Throwable ignore) {
467	>	} catch (Throwable ignore) {
468		}
469		}
470
#	Line 472 | Line 476 | public abstract class ForkJoinTask<V> im
476		ForkJoinTask<?> t;
477		while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null)
478		t.quietlyExec();
479	<	return (s >= 0)? awaitDone(w, false) : s; // block if no work
479	>	return (s >= 0) ? awaitDone(w, false) : s; // block if no work
480		}
481
482		// public methods
#	Line 482 | Line 486 | public abstract class ForkJoinTask<V> im
486		* necessarily enforced, it is a usage error to fork a task more
487		* than once unless it has completed and been reinitialized.  This
488		* method may be invoked only from within ForkJoinTask
489	<	* computations. Attempts to invoke in other contexts result in
490	<	* exceptions or errors possibly including ClassCastException.
489	>	* computations (as may be determined using method {@link
490	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
491	>	* in exceptions or errors, possibly including ClassCastException.
492		*/
493		public final void fork() {
494	<	((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this);
494	>	((ForkJoinWorkerThread) Thread.currentThread())
495	>	.pushTask(this);
496		}
497
498		/**
#	Line 522 | Line 528 | public abstract class ForkJoinTask<V> im
528		/**
529		* Forks both tasks, returning when {@code isDone} holds for
530		* both of them or an exception is encountered. This method may be
531	<	* invoked only from within ForkJoinTask computations. Attempts to
532	<	* invoke in other contexts result in exceptions or errors
531	>	* invoked only from within ForkJoinTask computations (as may be
532	>	* determined using method {@link #inForkJoinPool}). Attempts to
533	>	* invoke in other contexts result in exceptions or errors,
534		* possibly including ClassCastException.
535		*
536		* @param t1 one task
#	Line 541 | Line 548 | public abstract class ForkJoinTask<V> im
548		* Forks the given tasks, returning when {@code isDone} holds
549		* for all of them. If any task encounters an exception, others
550		* may be cancelled.  This method may be invoked only from within
551	<	* ForkJoinTask computations. Attempts to invoke in other contexts
552	<	* result in exceptions or errors possibly including ClassCastException.
551	>	* ForkJoinTask computations (as may be determined using method
552	>	* {@link #inForkJoinPool}). Attempts to invoke in other contexts
553	>	* result in exceptions or errors, possibly including
554	>	* ClassCastException.
555		*
556		* @param tasks the array of tasks
557		* @throws NullPointerException if tasks or any element are null
#	Line 585 | Line 594 | public abstract class ForkJoinTask<V> im
594		* Forks all tasks in the collection, returning when
595		* {@code isDone} holds for all of them. If any task
596		* encounters an exception, others may be cancelled.  This method
597	<	* may be invoked only from within ForkJoinTask
598	<	* computations. Attempts to invoke in other contexts result in
599	<	* exceptions or errors possibly including ClassCastException.
597	>	* may be invoked only from within ForkJoinTask computations (as
598	>	* may be determined using method {@link
599	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
600	>	* in exceptions or errors, possibly including ClassCastException.
601		*
602		* @param tasks the collection of tasks
603		* @throws NullPointerException if tasks or any element are null
#	Line 595 | Line 605 | public abstract class ForkJoinTask<V> im
605		*/
606		public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) {
607		if (!(tasks instanceof List)) {
608	<	invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()]));
608	>	invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()]));
609		return;
610		}
611		List<? extends ForkJoinTask<?>> ts =
612	<	(List<? extends ForkJoinTask<?>>)tasks;
612	>	(List<? extends ForkJoinTask<?>>) tasks;
613		Throwable ex = null;
614		int last = ts.size() - 1;
615		for (int i = last; i >= 0; --i) {
#	Line 674 | Line 684 | public abstract class ForkJoinTask<V> im
684		*
685		* @param mayInterruptIfRunning this value is ignored in the
686		* default implementation because tasks are not in general
687	<	* cancelled via interruption.
687	>	* cancelled via interruption
688		*
689		* @return true if this task is now cancelled
690		*/
#	Line 724 | Line 734 | public abstract class ForkJoinTask<V> im
734		*/
735		public void completeExceptionally(Throwable ex) {
736		setDoneExceptionally((ex instanceof RuntimeException) ||
737	<	(ex instanceof Error)? ex :
737	>	(ex instanceof Error) ? ex :
738		new RuntimeException(ex));
739		}
740
#	Line 743 | Line 753 | public abstract class ForkJoinTask<V> im
753		public void complete(V value) {
754		try {
755		setRawResult(value);
756	<	} catch(Throwable rex) {
756	>	} catch (Throwable rex) {
757		setDoneExceptionally(rex);
758		return;
759		}
#	Line 773 | Line 783 | public abstract class ForkJoinTask<V> im
783		* current task and that of any other task that might be executed
784		* while helping. (This usually holds for pure divide-and-conquer
785		* tasks). This method may be invoked only from within
786	<	* ForkJoinTask computations. Attempts to invoke in other contexts
787	<	* result in exceptions or errors possibly including ClassCastException.
786	>	* ForkJoinTask computations (as may be determined using method
787	>	* {@link #inForkJoinPool}). Attempts to invoke in other contexts
788	>	* result in exceptions or errors, possibly including
789	>	* ClassCastException.
790		*
791		* @return the computed result
792		*/
793		public final V helpJoin() {
794	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread());
794	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread();
795		if (status < 0 || !w.unpushTask(this) || !tryExec())
796		reportException(busyJoin(w));
797		return getRawResult();
#	Line 788 | Line 800 | public abstract class ForkJoinTask<V> im
800		/**
801		* Possibly executes other tasks until this task is ready.  This
802		* method may be invoked only from within ForkJoinTask
803	<	* computations. Attempts to invoke in other contexts result in
804	<	* exceptions or errors possibly including ClassCastException.
803	>	* computations (as may be determined using method {@link
804	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
805	>	* in exceptions or errors, possibly including ClassCastException.
806		*/
807		public final void quietlyHelpJoin() {
808		if (status >= 0) {
809		ForkJoinWorkerThread w =
810	<	(ForkJoinWorkerThread)(Thread.currentThread());
810	>	(ForkJoinWorkerThread) Thread.currentThread();
811		if (!w.unpushTask(this) || !tryQuietlyInvoke())
812		busyJoin(w);
813		}
#	Line 833 | Line 846 | public abstract class ForkJoinTask<V> im
846		* joined, instead executing them until all are processed.
847		*/
848		public static void helpQuiesce() {
849	<	((ForkJoinWorkerThread)(Thread.currentThread())).
850	<	helpQuiescePool();
849	>	((ForkJoinWorkerThread) Thread.currentThread())
850	>	.helpQuiescePool();
851		}
852
853		/**
#	Line 855 | Line 868 | public abstract class ForkJoinTask<V> im
868
869		/**
870		* Returns the pool hosting the current task execution, or null
871	<	* if this task is executing outside of any pool.
871	>	* if this task is executing outside of any ForkJoinPool.
872		*
873		* @return the pool, or null if none
874		*/
875		public static ForkJoinPool getPool() {
876		Thread t = Thread.currentThread();
877	<	return ((t instanceof ForkJoinWorkerThread)?
878	<	((ForkJoinWorkerThread)t).pool : null);
877	>	return ((t instanceof ForkJoinWorkerThread) ?
878	>	((ForkJoinWorkerThread) t).pool : null);
879	>	}
880	>
881	>	/**
882	>	* Returns {@code true} if the current thread is executing as a
883	>	* ForkJoinPool computation.
884	>	*
885	>	* @return {@code true} if the current thread is executing as a
886	>	* ForkJoinPool computation, or false otherwise
887	>	*/
888	>	public static boolean inForkJoinPool() {
889	>	return Thread.currentThread() instanceof ForkJoinWorkerThread;
890		}
891
892		/**
#	Line 872 | Line 896 | public abstract class ForkJoinTask<V> im
896		* another thread.  This method may be useful when arranging
897		* alternative local processing of tasks that could have been, but
898		* were not, stolen. This method may be invoked only from within
899	<	* ForkJoinTask computations. Attempts to invoke in other contexts
900	<	* result in exceptions or errors possibly including ClassCastException.
899	>	* ForkJoinTask computations (as may be determined using method
900	>	* {@link #inForkJoinPool}). Attempts to invoke in other contexts
901	>	* result in exceptions or errors, possibly including
902	>	* ClassCastException.
903		*
904		* @return true if unforked
905		*/
906		public boolean tryUnfork() {
907	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).unpushTask(this);
907	>	return ((ForkJoinWorkerThread) Thread.currentThread())
908	>	.unpushTask(this);
909		}
910
911		/**
#	Line 890 | Line 917 | public abstract class ForkJoinTask<V> im
917		* @return the number of tasks
918		*/
919		public static int getQueuedTaskCount() {
920	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
921	<	getQueueSize();
920	>	return ((ForkJoinWorkerThread) Thread.currentThread())
921	>	.getQueueSize();
922		}
923
924		/**
#	Line 907 | Line 934 | public abstract class ForkJoinTask<V> im
934		* @return the surplus number of tasks, which may be negative
935		*/
936		public static int getSurplusQueuedTaskCount() {
937	<	return ((ForkJoinWorkerThread)(Thread.currentThread()))
937	>	return ((ForkJoinWorkerThread) Thread.currentThread())
938		.getEstimatedSurplusTaskCount();
939		}
940
#	Line 954 | Line 981 | public abstract class ForkJoinTask<V> im
981		* be polled or executed next.  This method is designed primarily
982		* to support extensions, and is unlikely to be useful otherwise.
983		* This method may be invoked only from within ForkJoinTask
984	<	* computations. Attempts to invoke in other contexts result in
985	<	* exceptions or errors possibly including ClassCastException.
984	>	* computations (as may be determined using method {@link
985	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
986	>	* in exceptions or errors, possibly including ClassCastException.
987		*
988		* @return the next task, or null if none are available
989		*/
990		protected static ForkJoinTask<?> peekNextLocalTask() {
991	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).peekTask();
991	>	return ((ForkJoinWorkerThread) Thread.currentThread())
992	>	.peekTask();
993		}
994
995		/**
#	Line 968 | Line 997 | public abstract class ForkJoinTask<V> im
997		* queued by the current thread but not yet executed.  This method
998		* is designed primarily to support extensions, and is unlikely to
999		* be useful otherwise.  This method may be invoked only from
1000	<	* within ForkJoinTask computations. Attempts to invoke in other
1001	<	* contexts result in exceptions or errors possibly including
1000	>	* within ForkJoinTask computations (as may be determined using
1001	>	* method {@link #inForkJoinPool}). Attempts to invoke in other
1002	>	* contexts result in exceptions or errors, possibly including
1003		* ClassCastException.
1004		*
1005		* @return the next task, or null if none are available
1006		*/
1007		protected static ForkJoinTask<?> pollNextLocalTask() {
1008	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).pollLocalTask();
1008	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1009	>	.pollLocalTask();
1010		}
1011
1012		/**
#	Line 987 | Line 1018 | public abstract class ForkJoinTask<V> im
1018		* of the pool this task is operating in.  This method is designed
1019		* primarily to support extensions, and is unlikely to be useful
1020		* otherwise.  This method may be invoked only from within
1021	<	* ForkJoinTask computations. Attempts to invoke in other contexts
1022	<	* result in exceptions or errors possibly including
1021	>	* ForkJoinTask computations (as may be determined using method
1022	>	* {@link #inForkJoinPool}). Attempts to invoke in other contexts
1023	>	* result in exceptions or errors, possibly including
1024		* ClassCastException.
1025		*
1026		* @return a task, or null if none are available
1027		*/
1028		protected static ForkJoinTask<?> pollTask() {
1029	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
1030	<	pollTask();
1029	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1030	>	.pollTask();
1031		}
1032
1033		// Serialization support
#	Line 1027 | Line 1059 | public abstract class ForkJoinTask<V> im
1059		status |= EXTERNAL_SIGNAL; // conservatively set external signal
1060		Object ex = s.readObject();
1061		if (ex != null)
1062	<	setDoneExceptionally((Throwable)ex);
1062	>	setDoneExceptionally((Throwable) ex);
1063		}
1064
1065		// Temporary Unsafe mechanics for preliminary release

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