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

Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.13 by dl, Wed Jul 22 19:04:11 2009 UTC vs.
Revision 1.25 by dl, Fri Jul 31 16:27:08 2009 UTC

#	Line 5 | Line 5
5		*/
6
7		package jsr166y;
8	<	import java.io.Serializable;
9	<	import java.util.*;
8	>
9		import java.util.concurrent.*;
10	<	import java.util.concurrent.atomic.*;
11	<	import sun.misc.Unsafe;
12	<	import java.lang.reflect.*;
10	>
11	>	import java.io.Serializable;
12	>	import java.util.Collection;
13	>	import java.util.Collections;
14	>	import java.util.List;
15	>	import java.util.Map;
16	>	import java.util.WeakHashMap;
17
18		/**
19		* Abstract base class for tasks that run within a {@link
#	Line 22 | Line 25 | import java.lang.reflect.*;
25		* <p> A "main" ForkJoinTask begins execution when submitted to a
26		* {@link ForkJoinPool}. Once started, it will usually in turn start
27		* other subtasks.  As indicated by the name of this class, many
28	<	* programs using ForkJoinTasks employ only methods {@code fork}
29	<	* and {@code join}, or derivatives such as
30	<	* {@code invokeAll}.  However, this class also provides a number
31	<	* of other methods that can come into play in advanced usages, as
32	<	* well as extension mechanics that allow support of new forms of
30	<	* fork/join processing.
28	>	* programs using ForkJoinTasks employ only methods {@code fork} and
29	>	* {@code join}, or derivatives such as {@code invokeAll}.  However,
30	>	* this class also provides a number of other methods that can come
31	>	* into play in advanced usages, as well as extension mechanics that
32	>	* allow support of new forms of fork/join processing.
33		*
34		* <p>A ForkJoinTask is a lightweight form of {@link Future}.  The
35		* efficiency of ForkJoinTasks stems from a set of restrictions (that
#	Line 83 | Line 85 | import java.lang.reflect.*;
85		* methods), some of them may only be called from within other
86		* ForkJoinTasks (as may be determined using method {@link
87		* #inForkJoinPool}).  Attempts to invoke them in other contexts
88	<	* result in exceptions or errors possibly including
88	>	* result in exceptions or errors, possibly including
89		* ClassCastException.
90		*
91		* <p>Most base support methods are {@code final} because their
#	Line 91 | Line 93 | import java.lang.reflect.*;
93		* lightweight task scheduling framework, and so cannot be overridden.
94		* Developers creating new basic styles of fork/join processing should
95		* minimally implement {@code protected} methods
96	<	* {@code exec}, {@code setRawResult}, and
97	<	* {@code getRawResult}, while also introducing an abstract
96	>	* {@link #exec}, {@link #setRawResult}, and
97	>	* {@link #getRawResult}, while also introducing an abstract
98		* computational method that can be implemented in its subclasses,
99		* possibly relying on other {@code protected} methods provided
100		* by this class.
#	Line 162 | Line 164 | public abstract class ForkJoinTask<V> im
164		*/
165		static ForkJoinWorkerThread getWorker() {
166		Thread t = Thread.currentThread();
167	<	return ((t instanceof ForkJoinWorkerThread)?
168	<	(ForkJoinWorkerThread)t : null);
167	>	return ((t instanceof ForkJoinWorkerThread) ?
168	>	(ForkJoinWorkerThread) t : null);
169		}
170
171		final boolean casStatus(int cmp, int val) {
#	Line 189 | Line 191 | public abstract class ForkJoinTask<V> im
191		ForkJoinPool pool = getPool();
192		if (pool != null) {
193		int s; // Clear signal bits while setting completion status
194	<	do;while ((s = status) >= 0 && !casStatus(s, completion));
194	>	do {} while ((s = status) >= 0 && !casStatus(s, completion));
195
196		if ((s & SIGNAL_MASK) != 0) {
197		if ((s &= INTERNAL_SIGNAL_MASK) != 0)
198		pool.updateRunningCount(s);
199	<	synchronized(this) { notifyAll(); }
199	>	synchronized (this) { notifyAll(); }
200		}
201		}
202		else
#	Line 207 | Line 209 | public abstract class ForkJoinTask<V> im
209		*/
210		private void externallySetCompletion(int completion) {
211		int s;
212	<	do;while ((s = status) >= 0 &&
213	<	!casStatus(s, (s & SIGNAL_MASK) | completion));
214	<	synchronized(this) { notifyAll(); }
212	>	do {} while ((s = status) >= 0 &&
213	>	!casStatus(s, (s & SIGNAL_MASK) | completion));
214	>	synchronized (this) { notifyAll(); }
215		}
216
217		/**
218	<	* Sets status to indicate normal completion
218	>	* Sets status to indicate normal completion.
219		*/
220		final void setNormalCompletion() {
221		// Try typical fast case -- single CAS, no signal, not already done.
#	Line 225 | Line 227 | public abstract class ForkJoinTask<V> im
227		// internal waiting and notification
228
229		/**
230	<	* Performs the actual monitor wait for awaitDone
230	>	* Performs the actual monitor wait for awaitDone.
231		*/
232		private void doAwaitDone() {
233		// Minimize lock bias and in/de-flation effects by maximizing
234		// chances of waiting inside sync
235		try {
236		while (status >= 0)
237	<	synchronized(this) { if (status >= 0) wait(); }
237	>	synchronized (this) { if (status >= 0) wait(); }
238		} catch (InterruptedException ie) {
239		onInterruptedWait();
240		}
241		}
242
243		/**
244	<	* Performs the actual monitor wait for awaitDone
244	>	* Performs the actual timed monitor wait for awaitDone.
245		*/
246		private void doAwaitDone(long startTime, long nanos) {
247	<	synchronized(this) {
247	>	synchronized (this) {
248		try {
249		while (status >= 0) {
250	<	long nt = nanos - System.nanoTime() - startTime;
250	>	long nt = nanos - (System.nanoTime() - startTime);
251		if (nt <= 0)
252		break;
253	<	wait(nt / 1000000, (int)(nt % 1000000));
253	>	wait(nt / 1000000, (int) (nt % 1000000));
254		}
255		} catch (InterruptedException ie) {
256		onInterruptedWait();
#	Line 264 | Line 266 | public abstract class ForkJoinTask<V> im
266		*
267		* @return status upon exit
268		*/
269	<	private int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) {
270	<	ForkJoinPool pool = w == null? null : w.pool;
269	>	private int awaitDone(ForkJoinWorkerThread w,
270	>	boolean maintainParallelism) {
271	>	ForkJoinPool pool = (w == null) ? null : w.pool;
272		int s;
273		while ((s = status) >= 0) {
274	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
274	>	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
275		if (pool == null || !pool.preJoin(this, maintainParallelism))
276		doAwaitDone();
277		if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
#	Line 281 | Line 284 | public abstract class ForkJoinTask<V> im
284
285		/**
286		* Timed version of awaitDone
287	+	*
288		* @return status upon exit
289		*/
290		private int awaitDone(ForkJoinWorkerThread w, long nanos) {
291	<	ForkJoinPool pool = w == null? null : w.pool;
291	>	ForkJoinPool pool = (w == null) ? null : w.pool;
292		int s;
293		while ((s = status) >= 0) {
294	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
294	>	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
295		long startTime = System.nanoTime();
296		if (pool == null || !pool.preJoin(this, false))
297		doAwaitDone(startTime, nanos);
#	Line 309 | Line 313 | public abstract class ForkJoinTask<V> im
313		*/
314		private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
315		int s;
316	<	do;while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
316	>	do {} while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
317		if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
318		pool.updateRunningCount(s);
319		}
#	Line 364 | Line 368 | public abstract class ForkJoinTask<V> im
368
369		/**
370		* Returns result or throws exception using j.u.c.Future conventions.
371	<	* Only call when isDone known to be true.
371	>	* Only call when {@code isDone} known to be true.
372		*/
373		private V reportFutureResult()
374		throws ExecutionException, InterruptedException {
#	Line 430 | Line 434 | public abstract class ForkJoinTask<V> im
434		try {
435		if (!exec())
436		return;
437	<	} catch(Throwable rex) {
437	>	} catch (Throwable rex) {
438		setDoneExceptionally(rex);
439		return;
440		}
#	Line 462 | Line 466 | public abstract class ForkJoinTask<V> im
466		final void cancelIgnoringExceptions() {
467		try {
468		cancel(false);
469	<	} catch(Throwable ignore) {
469	>	} catch (Throwable ignore) {
470		}
471		}
472
#	Line 474 | Line 478 | public abstract class ForkJoinTask<V> im
478		ForkJoinTask<?> t;
479		while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null)
480		t.quietlyExec();
481	<	return (s >= 0)? awaitDone(w, false) : s; // block if no work
481	>	return (s >= 0) ? awaitDone(w, false) : s; // block if no work
482		}
483
484		// public methods
#	Line 486 | Line 490 | public abstract class ForkJoinTask<V> im
490		* method may be invoked only from within ForkJoinTask
491		* computations (as may be determined using method {@link
492		* #inForkJoinPool}). Attempts to invoke in other contexts result
493	<	* in exceptions or errors possibly including ClassCastException.
493	>	* in exceptions or errors, possibly including ClassCastException.
494	>	*
495	>	* @return {@code this}, to simplify usage.
496		*/
497	<	public final void fork() {
498	<	((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this);
497	>	public final ForkJoinTask<V> fork() {
498	>	((ForkJoinWorkerThread) Thread.currentThread())
499	>	.pushTask(this);
500	>	return this;
501		}
502
503		/**
#	Line 527 | Line 535 | public abstract class ForkJoinTask<V> im
535		* both of them or an exception is encountered. This method may be
536		* invoked only from within ForkJoinTask computations (as may be
537		* determined using method {@link #inForkJoinPool}). Attempts to
538	<	* invoke in other contexts result in exceptions or errors
538	>	* invoke in other contexts result in exceptions or errors,
539		* possibly including ClassCastException.
540		*
541		* @param t1 one task
#	Line 547 | Line 555 | public abstract class ForkJoinTask<V> im
555		* may be cancelled.  This method may be invoked only from within
556		* ForkJoinTask computations (as may be determined using method
557		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
558	<	* result in exceptions or errors possibly including
558	>	* result in exceptions or errors, possibly including
559		* ClassCastException.
560	+	*
561		* @param tasks the array of tasks
562		* @throws NullPointerException if tasks or any element are null
563		* @throws RuntimeException or Error if any task did so
#	Line 592 | Line 601 | public abstract class ForkJoinTask<V> im
601		* encounters an exception, others may be cancelled.  This method
602		* may be invoked only from within ForkJoinTask computations (as
603		* may be determined using method {@link
604	<	* #inForkJoinPool}). Attempts to invoke in other contexts resul!t
605	<	* in exceptions or errors possibly including ClassCastException.
604	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
605	>	* in exceptions or errors, possibly including ClassCastException.
606		*
607		* @param tasks the collection of tasks
608	+	* @return the tasks argument, to simplify usage
609		* @throws NullPointerException if tasks or any element are null
610		* @throws RuntimeException or Error if any task did so
611		*/
612	<	public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) {
613	<	if (!(tasks instanceof List)) {
614	<	invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()]));
615	<	return;
612	>	public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) {
613	>	if (!(tasks instanceof List<?>)) {
614	>	invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()]));
615	>	return tasks;
616		}
617	+	@SuppressWarnings("unchecked")
618		List<? extends ForkJoinTask<?>> ts =
619	<	(List<? extends ForkJoinTask<?>>)tasks;
619	>	(List<? extends ForkJoinTask<?>>) tasks;
620		Throwable ex = null;
621		int last = ts.size() - 1;
622		for (int i = last; i >= 0; --i) {
#	Line 636 | Line 647 | public abstract class ForkJoinTask<V> im
647		}
648		if (ex != null)
649		rethrowException(ex);
650	+	return tasks;
651		}
652
653		/**
654	<	* Returns true if the computation performed by this task has
655	<	* completed (or has been cancelled).
654	>	* Returns {@code true} if the computation performed by this task
655	>	* has completed (or has been cancelled).
656		*
657	<	* @return true if this computation has completed
657	>	* @return {@code true} if this computation has completed
658		*/
659		public final boolean isDone() {
660		return status < 0;
661		}
662
663		/**
664	<	* Returns true if this task was cancelled.
664	>	* Returns {@code true} if this task was cancelled.
665		*
666	<	* @return true if this task was cancelled
666	>	* @return {@code true} if this task was cancelled
667		*/
668		public final boolean isCancelled() {
669		return (status & COMPLETION_MASK) == CANCELLED;
#	Line 660 | Line 672 | public abstract class ForkJoinTask<V> im
672		/**
673		* Asserts that the results of this task's computation will not be
674		* used. If a cancellation occurs before attempting to execute this
675	<	* task, then execution will be suppressed, {@code isCancelled}
676	<	* will report true, and {@code join} will result in a
675	>	* task, execution will be suppressed, {@link #isCancelled}
676	>	* will report true, and {@link #join} will result in a
677		* {@code CancellationException} being thrown. Otherwise, when
678		* cancellation races with completion, there are no guarantees
679	<	* about whether {@code isCancelled} will report true, whether
680	<	* {@code join} will return normally or via an exception, or
681	<	* whether these behaviors will remain consistent upon repeated
679	>	* about whether {@code isCancelled} will report {@code true},
680	>	* whether {@code join} will return normally or via an exception,
681	>	* or whether these behaviors will remain consistent upon repeated
682		* invocation.
683		*
684		* <p>This method may be overridden in subclasses, but if so, must
#	Line 676 | Line 688 | public abstract class ForkJoinTask<V> im
688		* <p> This method is designed to be invoked by <em>other</em>
689		* tasks. To terminate the current task, you can just return or
690		* throw an unchecked exception from its computation method, or
691	<	* invoke {@code completeExceptionally}.
691	>	* invoke {@link #completeExceptionally}.
692		*
693		* @param mayInterruptIfRunning this value is ignored in the
694		* default implementation because tasks are not in general
695	<	* cancelled via interruption.
695	>	* cancelled via interruption
696		*
697	<	* @return true if this task is now cancelled
697	>	* @return {@code true} if this task is now cancelled
698		*/
699		public boolean cancel(boolean mayInterruptIfRunning) {
700		setCompletion(CANCELLED);
#	Line 690 | Line 702 | public abstract class ForkJoinTask<V> im
702		}
703
704		/**
705	<	* Returns true if this task threw an exception or was cancelled.
705	>	* Returns {@code true} if this task threw an exception or was cancelled.
706		*
707	<	* @return true if this task threw an exception or was cancelled
707	>	* @return {@code true} if this task threw an exception or was cancelled
708		*/
709		public final boolean isCompletedAbnormally() {
710		return (status & COMPLETION_MASK) < NORMAL;
#	Line 703 | Line 715 | public abstract class ForkJoinTask<V> im
715		* CancellationException if cancelled, or null if none or if the
716		* method has not yet completed.
717		*
718	<	* @return the exception, or null if none
718	>	* @return the exception, or {@code null} if none
719		*/
720		public final Throwable getException() {
721		int s = status & COMPLETION_MASK;
#	Line 730 | Line 742 | public abstract class ForkJoinTask<V> im
742		*/
743		public void completeExceptionally(Throwable ex) {
744		setDoneExceptionally((ex instanceof RuntimeException) ||
745	<	(ex instanceof Error)? ex :
745	>	(ex instanceof Error) ? ex :
746		new RuntimeException(ex));
747		}
748
#	Line 749 | Line 761 | public abstract class ForkJoinTask<V> im
761		public void complete(V value) {
762		try {
763		setRawResult(value);
764	<	} catch(Throwable rex) {
764	>	} catch (Throwable rex) {
765		setDoneExceptionally(rex);
766		return;
767		}
#	Line 765 | Line 777 | public abstract class ForkJoinTask<V> im
777
778		public final V get(long timeout, TimeUnit unit)
779		throws InterruptedException, ExecutionException, TimeoutException {
780	+	long nanos = unit.toNanos(timeout);
781		ForkJoinWorkerThread w = getWorker();
782		if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
783	<	awaitDone(w, unit.toNanos(timeout));
783	>	awaitDone(w, nanos);
784		return reportTimedFutureResult();
785		}
786
#	Line 781 | Line 794 | public abstract class ForkJoinTask<V> im
794		* tasks). This method may be invoked only from within
795		* ForkJoinTask computations (as may be determined using method
796		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
797	<	* resul!t in exceptions or errors possibly including
797	>	* result in exceptions or errors, possibly including
798		* ClassCastException.
799		*
800		* @return the computed result
801		*/
802		public final V helpJoin() {
803	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread());
803	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread();
804		if (status < 0 || !w.unpushTask(this) || !tryExec())
805		reportException(busyJoin(w));
806		return getRawResult();
#	Line 797 | Line 810 | public abstract class ForkJoinTask<V> im
810		* Possibly executes other tasks until this task is ready.  This
811		* method may be invoked only from within ForkJoinTask
812		* computations (as may be determined using method {@link
813	<	* #inForkJoinPool}). Attempts to invoke in other contexts resul!t
814	<	* in exceptions or errors possibly including ClassCastException.
813	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
814	>	* in exceptions or errors, possibly including ClassCastException.
815		*/
816		public final void quietlyHelpJoin() {
817		if (status >= 0) {
818		ForkJoinWorkerThread w =
819	<	(ForkJoinWorkerThread)(Thread.currentThread());
819	>	(ForkJoinWorkerThread) Thread.currentThread();
820		if (!w.unpushTask(this) || !tryQuietlyInvoke())
821		busyJoin(w);
822		}
#	Line 842 | Line 855 | public abstract class ForkJoinTask<V> im
855		* joined, instead executing them until all are processed.
856		*/
857		public static void helpQuiesce() {
858	<	((ForkJoinWorkerThread)(Thread.currentThread())).
859	<	helpQuiescePool();
858	>	((ForkJoinWorkerThread) Thread.currentThread())
859	>	.helpQuiescePool();
860		}
861
862		/**
#	Line 866 | Line 879 | public abstract class ForkJoinTask<V> im
879		* Returns the pool hosting the current task execution, or null
880		* if this task is executing outside of any ForkJoinPool.
881		*
882	<	* @return the pool, or null if none.
882	>	* @return the pool, or {@code null} if none
883		*/
884		public static ForkJoinPool getPool() {
885		Thread t = Thread.currentThread();
886	<	return ((t instanceof ForkJoinWorkerThread)?
887	<	((ForkJoinWorkerThread)t).pool : null);
886	>	return (t instanceof ForkJoinWorkerThread) ?
887	>	((ForkJoinWorkerThread) t).pool : null;
888		}
889
890		/**
891	<	* Returns true if the current thread is executing as a
891	>	* Returns {@code true} if the current thread is executing as a
892		* ForkJoinPool computation.
893	<	* @return <code>true</code> if the current thread is executing as a
893	>	*
894	>	* @return {@code true} if the current thread is executing as a
895		* ForkJoinPool computation, or false otherwise
896		*/
897		public static boolean inForkJoinPool() {
#	Line 893 | Line 907 | public abstract class ForkJoinTask<V> im
907		* were not, stolen. This method may be invoked only from within
908		* ForkJoinTask computations (as may be determined using method
909		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
910	<	* result in exceptions or errors possibly including
910	>	* result in exceptions or errors, possibly including
911		* ClassCastException.
912		*
913	<	* @return true if unforked
913	>	* @return {@code true} if unforked
914		*/
915		public boolean tryUnfork() {
916	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).unpushTask(this);
916	>	return ((ForkJoinWorkerThread) Thread.currentThread())
917	>	.unpushTask(this);
918		}
919
920		/**
#	Line 911 | Line 926 | public abstract class ForkJoinTask<V> im
926		* @return the number of tasks
927		*/
928		public static int getQueuedTaskCount() {
929	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
930	<	getQueueSize();
929	>	return ((ForkJoinWorkerThread) Thread.currentThread())
930	>	.getQueueSize();
931		}
932
933		/**
#	Line 928 | Line 943 | public abstract class ForkJoinTask<V> im
943		* @return the surplus number of tasks, which may be negative
944		*/
945		public static int getSurplusQueuedTaskCount() {
946	<	return ((ForkJoinWorkerThread)(Thread.currentThread()))
946	>	return ((ForkJoinWorkerThread) Thread.currentThread())
947		.getEstimatedSurplusTaskCount();
948		}
949
950		// Extension methods
951
952		/**
953	<	* Returns the result that would be returned by {@code join},
954	<	* even if this task completed abnormally, or null if this task is
955	<	* not known to have been completed.  This method is designed to
956	<	* aid debugging, as well as to support extensions. Its use in any
957	<	* other context is discouraged.
953	>	* Returns the result that would be returned by {@link #join}, even
954	>	* if this task completed abnormally, or {@code null} if this task
955	>	* is not known to have been completed.  This method is designed
956	>	* to aid debugging, as well as to support extensions. Its use in
957	>	* any other context is discouraged.
958		*
959	<	* @return the result, or null if not completed
959	>	* @return the result, or {@code null} if not completed
960		*/
961		public abstract V getRawResult();
962
#	Line 960 | Line 975 | public abstract class ForkJoinTask<V> im
975		* called otherwise. The return value controls whether this task
976		* is considered to be done normally. It may return false in
977		* asynchronous actions that require explicit invocations of
978	<	* {@code complete} to become joinable. It may throw exceptions
978	>	* {@link #complete} to become joinable. It may throw exceptions
979		* to indicate abnormal exit.
980		*
981	<	* @return true if completed normally
981	>	* @return {@code true} if completed normally
982		* @throws Error or RuntimeException if encountered during computation
983		*/
984		protected abstract boolean exec();
985
986		/**
987	<	* Returns, but does not unschedule or execute, the task queued by
988	<	* the current thread but not yet executed, if one is
987	>	* Returns, but does not unschedule or execute, a task queued by
988	>	* the current thread but not yet executed, if one is immediately
989		* available. There is no guarantee that this task will actually
990	<	* be polled or executed next.  This method is designed primarily
991	<	* to support extensions, and is unlikely to be useful otherwise.
992	<	* This method may be invoked only from within ForkJoinTask
993	<	* computations (as may be determined using method {@link
994	<	* #inForkJoinPool}). Attempts to invoke in other contexts result
995	<	* in exceptions or errors possibly including ClassCastException.
990	>	* be polled or executed next. Conversely, this method may return
991	>	* null even if a task exists but cannot be accessed without
992	>	* contention with other threads.  This method is designed
993	>	* primarily to support extensions, and is unlikely to be useful
994	>	* otherwise.  This method may be invoked only from within
995	>	* ForkJoinTask computations (as may be determined using method
996	>	* {@link #inForkJoinPool}). Attempts to invoke in other contexts
997	>	* result in exceptions or errors, possibly including
998	>	* ClassCastException.
999		*
1000	<	* @return the next task, or null if none are available
1000	>	* @return the next task, or {@code null} if none are available
1001		*/
1002		protected static ForkJoinTask<?> peekNextLocalTask() {
1003	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).peekTask();
1003	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1004	>	.peekTask();
1005		}
1006
1007		/**
#	Line 992 | Line 1011 | public abstract class ForkJoinTask<V> im
1011		* be useful otherwise.  This method may be invoked only from
1012		* within ForkJoinTask computations (as may be determined using
1013		* method {@link #inForkJoinPool}). Attempts to invoke in other
1014	<	* contexts result in exceptions or errors possibly including
1014	>	* contexts result in exceptions or errors, possibly including
1015		* ClassCastException.
1016		*
1017	<	* @return the next task, or null if none are available
1017	>	* @return the next task, or {@code null} if none are available
1018		*/
1019		protected static ForkJoinTask<?> pollNextLocalTask() {
1020	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).pollLocalTask();
1020	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1021	>	.pollLocalTask();
1022		}
1023
1024		/**
#	Line 1012 | Line 1032 | public abstract class ForkJoinTask<V> im
1032		* otherwise.  This method may be invoked only from within
1033		* ForkJoinTask computations (as may be determined using method
1034		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
1035	<	* result in exceptions or errors possibly including
1035	>	* result in exceptions or errors, possibly including
1036		* ClassCastException.
1037		*
1038	<	* @return a task, or null if none are available
1038	>	* @return a task, or {@code null} if none are available
1039		*/
1040		protected static ForkJoinTask<?> pollTask() {
1041	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
1042	<	pollTask();
1041	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1042	>	.pollTask();
1043	>	}
1044	>
1045	>	/**
1046	>	* Adaptor for Runnables. This implements RunnableFuture
1047	>	* to be compliant with AbstractExecutorService constraints
1048	>	* when used in ForkJoinPool.
1049	>	*/
1050	>	static final class AdaptedRunnable<T> extends ForkJoinTask<T>
1051	>	implements RunnableFuture<T> {
1052	>	final Runnable runnable;
1053	>	final T resultOnCompletion;
1054	>	T result;
1055	>	AdaptedRunnable(Runnable runnable, T result) {
1056	>	if (runnable == null) throw new NullPointerException();
1057	>	this.runnable = runnable;
1058	>	this.resultOnCompletion = result;
1059	>	}
1060	>	public T getRawResult() { return result; }
1061	>	public void setRawResult(T v) { result = v; }
1062	>	public boolean exec() {
1063	>	runnable.run();
1064	>	result = resultOnCompletion;
1065	>	return true;
1066	>	}
1067	>	public void run() { invoke(); }
1068	>	private static final long serialVersionUID = 5232453952276885070L;
1069	>	}
1070	>
1071	>	/**
1072	>	* Adaptor for Callables
1073	>	*/
1074	>	static final class AdaptedCallable<T> extends ForkJoinTask<T>
1075	>	implements RunnableFuture<T> {
1076	>	final Callable<T> callable;
1077	>	T result;
1078	>	AdaptedCallable(Callable<T> callable) {
1079	>	if (callable == null) throw new NullPointerException();
1080	>	this.callable = callable;
1081	>	}
1082	>	public T getRawResult() { return result; }
1083	>	public void setRawResult(T v) { result = v; }
1084	>	public boolean exec() {
1085	>	try {
1086	>	result = callable.call();
1087	>	return true;
1088	>	} catch (Error err) {
1089	>	throw err;
1090	>	} catch (RuntimeException rex) {
1091	>	throw rex;
1092	>	} catch (Exception ex) {
1093	>	throw new RuntimeException(ex);
1094	>	}
1095	>	}
1096	>	public void run() { invoke(); }
1097	>	private static final long serialVersionUID = 2838392045355241008L;
1098	>	}
1099	>
1100	>	/**
1101	>	* Returns a new ForkJoinTask that performs the {@code run}
1102	>	* method of the given Runnable as its action, and returns a null
1103	>	* result upon {@code join}.
1104	>	*
1105	>	* @param runnable the runnable action
1106	>	* @return the task
1107	>	*/
1108	>	public static ForkJoinTask<Void> adapt(Runnable runnable) {
1109	>	return new AdaptedRunnable<Void>(runnable, null);
1110	>	}
1111	>
1112	>	/**
1113	>	* Returns a new ForkJoinTask that performs the {@code run}
1114	>	* method of the given Runnable as its action, and returns the
1115	>	* given result upon {@code join}.
1116	>	*
1117	>	* @param runnable the runnable action
1118	>	* @param result the result upon completion
1119	>	* @return the task
1120	>	*/
1121	>	public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) {
1122	>	return new AdaptedRunnable<T>(runnable, result);
1123	>	}
1124	>
1125	>	/**
1126	>	* Returns a new ForkJoinTask that performs the {@code call}
1127	>	* method of the given Callable as its action, and returns its
1128	>	* result upon {@code join}, translating any checked
1129	>	* exceptions encountered into {@code RuntimeException}.
1130	>	*
1131	>	* @param callable the callable action
1132	>	* @return the task
1133	>	*/
1134	>	public static <T> ForkJoinTask<T> adapt(Callable<T> callable) {
1135	>	return new AdaptedCallable<T>(callable);
1136		}
1137
1138		// Serialization support
#	Line 1030 | Line 1143 | public abstract class ForkJoinTask<V> im
1143		* Save the state to a stream.
1144		*
1145		* @serialData the current run status and the exception thrown
1146	<	* during execution, or null if none
1146	>	* during execution, or {@code null} if none
1147		* @param s the stream
1148		*/
1149		private void writeObject(java.io.ObjectOutputStream s)
#	Line 1051 | Line 1164 | public abstract class ForkJoinTask<V> im
1164		status |= EXTERNAL_SIGNAL; // conservatively set external signal
1165		Object ex = s.readObject();
1166		if (ex != null)
1167	<	setDoneExceptionally((Throwable)ex);
1167	>	setDoneExceptionally((Throwable) ex);
1168		}
1169
1170	<	// Temporary Unsafe mechanics for preliminary release
1171	<	private static Unsafe getUnsafe() throws Throwable {
1170	>	// Unsafe mechanics
1171	>
1172	>	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1173	>	private static final long statusOffset =
1174	>	objectFieldOffset("status", ForkJoinTask.class);
1175	>
1176	>	private static long objectFieldOffset(String field, Class<?> klazz) {
1177		try {
1178	<	return Unsafe.getUnsafe();
1178	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
1179	>	} catch (NoSuchFieldException e) {
1180	>	// Convert Exception to corresponding Error
1181	>	NoSuchFieldError error = new NoSuchFieldError(field);
1182	>	error.initCause(e);
1183	>	throw error;
1184	>	}
1185	>	}
1186	>
1187	>	/**
1188	>	* Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
1189	>	* Replace with a simple call to Unsafe.getUnsafe when integrating
1190	>	* into a jdk.
1191	>	*
1192	>	* @return a sun.misc.Unsafe
1193	>	*/
1194	>	private static sun.misc.Unsafe getUnsafe() {
1195	>	try {
1196	>	return sun.misc.Unsafe.getUnsafe();
1197		} catch (SecurityException se) {
1198		try {
1199		return java.security.AccessController.doPrivileged
1200	<	(new java.security.PrivilegedExceptionAction<Unsafe>() {
1201	<	public Unsafe run() throws Exception {
1202	<	return getUnsafePrivileged();
1200	>	(new java.security
1201	>	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1202	>	public sun.misc.Unsafe run() throws Exception {
1203	>	java.lang.reflect.Field f = sun.misc
1204	>	.Unsafe.class.getDeclaredField("theUnsafe");
1205	>	f.setAccessible(true);
1206	>	return (sun.misc.Unsafe) f.get(null);
1207		}});
1208		} catch (java.security.PrivilegedActionException e) {
1209	<	throw e.getCause();
1209	>	throw new RuntimeException("Could not initialize intrinsics",
1210	>	e.getCause());
1211		}
1212		}
1213		}
1073	–
1074	–	private static Unsafe getUnsafePrivileged()
1075	–	throws NoSuchFieldException, IllegalAccessException {
1076	–	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1077	–	f.setAccessible(true);
1078	–	return (Unsafe) f.get(null);
1079	–	}
1080	–
1081	–	private static long fieldOffset(String fieldName)
1082	–	throws NoSuchFieldException {
1083	–	return UNSAFE.objectFieldOffset
1084	–	(ForkJoinTask.class.getDeclaredField(fieldName));
1085	–	}
1086	–
1087	–	static final Unsafe UNSAFE;
1088	–	static final long statusOffset;
1089	–
1090	–	static {
1091	–	try {
1092	–	UNSAFE = getUnsafe();
1093	–	statusOffset = fieldOffset("status");
1094	–	} catch (Throwable e) {
1095	–	throw new RuntimeException("Could not initialize intrinsics", e);
1096	–	}
1097	–	}
1098	–
1214		}

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