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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 1.16 by jsr166, Fri Jul 24 23:47:01 2009 UTC

#	Line 9 | Line 9 | import java.io.Serializable;
9		import java.util.*;
10		import java.util.concurrent.*;
11		import java.util.concurrent.atomic.*;
12	–	import sun.misc.Unsafe;
13	–	import java.lang.reflect.*;
12
13		/**
14		* Abstract base class for tasks that run within a {@link
#	Line 83 | Line 81 | import java.lang.reflect.*;
81		* methods), some of them may only be called from within other
82		* ForkJoinTasks (as may be determined using method {@link
83		* #inForkJoinPool}).  Attempts to invoke them in other contexts
84	<	* result in exceptions or errors possibly including
84	>	* result in exceptions or errors, possibly including
85		* ClassCastException.
86		*
87		* <p>Most base support methods are {@code final} because their
#	Line 162 | Line 160 | public abstract class ForkJoinTask<V> im
160		*/
161		static ForkJoinWorkerThread getWorker() {
162		Thread t = Thread.currentThread();
163	<	return ((t instanceof ForkJoinWorkerThread)?
164	<	(ForkJoinWorkerThread)t : null);
163	>	return ((t instanceof ForkJoinWorkerThread) ?
164	>	(ForkJoinWorkerThread) t : null);
165		}
166
167		final boolean casStatus(int cmp, int val) {
#	Line 189 | Line 187 | public abstract class ForkJoinTask<V> im
187		ForkJoinPool pool = getPool();
188		if (pool != null) {
189		int s; // Clear signal bits while setting completion status
190	<	do;while ((s = status) >= 0 && !casStatus(s, completion));
190	>	do {} while ((s = status) >= 0 && !casStatus(s, completion));
191
192		if ((s & SIGNAL_MASK) != 0) {
193		if ((s &= INTERNAL_SIGNAL_MASK) != 0)
194		pool.updateRunningCount(s);
195	<	synchronized(this) { notifyAll(); }
195	>	synchronized (this) { notifyAll(); }
196		}
197		}
198		else
#	Line 207 | Line 205 | public abstract class ForkJoinTask<V> im
205		*/
206		private void externallySetCompletion(int completion) {
207		int s;
208	<	do;while ((s = status) >= 0 &&
209	<	!casStatus(s, (s & SIGNAL_MASK) | completion));
210	<	synchronized(this) { notifyAll(); }
208	>	do {} while ((s = status) >= 0 &&
209	>	!casStatus(s, (s & SIGNAL_MASK) | completion));
210	>	synchronized (this) { notifyAll(); }
211		}
212
213		/**
214	<	* Sets status to indicate normal completion
214	>	* Sets status to indicate normal completion.
215		*/
216		final void setNormalCompletion() {
217		// Try typical fast case -- single CAS, no signal, not already done.
#	Line 225 | Line 223 | public abstract class ForkJoinTask<V> im
223		// internal waiting and notification
224
225		/**
226	<	* Performs the actual monitor wait for awaitDone
226	>	* Performs the actual monitor wait for awaitDone.
227		*/
228		private void doAwaitDone() {
229		// Minimize lock bias and in/de-flation effects by maximizing
230		// chances of waiting inside sync
231		try {
232		while (status >= 0)
233	<	synchronized(this) { if (status >= 0) wait(); }
233	>	synchronized (this) { if (status >= 0) wait(); }
234		} catch (InterruptedException ie) {
235		onInterruptedWait();
236		}
237		}
238
239		/**
240	<	* Performs the actual monitor wait for awaitDone
240	>	* Performs the actual timed monitor wait for awaitDone.
241		*/
242		private void doAwaitDone(long startTime, long nanos) {
243	<	synchronized(this) {
243	>	synchronized (this) {
244		try {
245		while (status >= 0) {
246		long nt = nanos - System.nanoTime() - startTime;
247		if (nt <= 0)
248		break;
249	<	wait(nt / 1000000, (int)(nt % 1000000));
249	>	wait(nt / 1000000, (int) (nt % 1000000));
250		}
251		} catch (InterruptedException ie) {
252		onInterruptedWait();
#	Line 264 | Line 262 | public abstract class ForkJoinTask<V> im
262		*
263		* @return status upon exit
264		*/
265	<	private int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) {
266	<	ForkJoinPool pool = w == null? null : w.pool;
265	>	private int awaitDone(ForkJoinWorkerThread w,
266	>	boolean maintainParallelism) {
267	>	ForkJoinPool pool = (w == null) ? null : w.pool;
268		int s;
269		while ((s = status) >= 0) {
270	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
270	>	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
271		if (pool == null || !pool.preJoin(this, maintainParallelism))
272		doAwaitDone();
273		if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
#	Line 281 | Line 280 | public abstract class ForkJoinTask<V> im
280
281		/**
282		* Timed version of awaitDone
283	+	*
284		* @return status upon exit
285		*/
286		private int awaitDone(ForkJoinWorkerThread w, long nanos) {
287	<	ForkJoinPool pool = w == null? null : w.pool;
287	>	ForkJoinPool pool = (w == null) ? null : w.pool;
288		int s;
289		while ((s = status) >= 0) {
290	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
290	>	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
291		long startTime = System.nanoTime();
292		if (pool == null || !pool.preJoin(this, false))
293		doAwaitDone(startTime, nanos);
#	Line 309 | Line 309 | public abstract class ForkJoinTask<V> im
309		*/
310		private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
311		int s;
312	<	do;while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
312	>	do {} while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
313		if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
314		pool.updateRunningCount(s);
315		}
#	Line 364 | Line 364 | public abstract class ForkJoinTask<V> im
364
365		/**
366		* Returns result or throws exception using j.u.c.Future conventions.
367	<	* Only call when isDone known to be true.
367	>	* Only call when {@code isDone} known to be true.
368		*/
369		private V reportFutureResult()
370		throws ExecutionException, InterruptedException {
#	Line 430 | Line 430 | public abstract class ForkJoinTask<V> im
430		try {
431		if (!exec())
432		return;
433	<	} catch(Throwable rex) {
433	>	} catch (Throwable rex) {
434		setDoneExceptionally(rex);
435		return;
436		}
#	Line 462 | Line 462 | public abstract class ForkJoinTask<V> im
462		final void cancelIgnoringExceptions() {
463		try {
464		cancel(false);
465	<	} catch(Throwable ignore) {
465	>	} catch (Throwable ignore) {
466		}
467		}
468
#	Line 474 | Line 474 | public abstract class ForkJoinTask<V> im
474		ForkJoinTask<?> t;
475		while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null)
476		t.quietlyExec();
477	<	return (s >= 0)? awaitDone(w, false) : s; // block if no work
477	>	return (s >= 0) ? awaitDone(w, false) : s; // block if no work
478		}
479
480		// public methods
#	Line 486 | Line 486 | public abstract class ForkJoinTask<V> im
486		* method may be invoked only from within ForkJoinTask
487		* computations (as may be determined using method {@link
488		* #inForkJoinPool}). Attempts to invoke in other contexts result
489	<	* in exceptions or errors possibly including ClassCastException.
489	>	* in exceptions or errors, possibly including ClassCastException.
490		*/
491		public final void fork() {
492	<	((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this);
492	>	((ForkJoinWorkerThread) Thread.currentThread())
493	>	.pushTask(this);
494		}
495
496		/**
#	Line 527 | Line 528 | public abstract class ForkJoinTask<V> im
528		* both of them or an exception is encountered. This method may be
529		* invoked only from within ForkJoinTask computations (as may be
530		* determined using method {@link #inForkJoinPool}). Attempts to
531	<	* invoke in other contexts result in exceptions or errors
531	>	* invoke in other contexts result in exceptions or errors,
532		* possibly including ClassCastException.
533		*
534		* @param t1 one task
#	Line 547 | Line 548 | public abstract class ForkJoinTask<V> im
548		* may be cancelled.  This method may be invoked only from within
549		* ForkJoinTask computations (as may be determined using method
550		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
551	<	* result in exceptions or errors possibly including
551	>	* result in exceptions or errors, possibly including
552		* ClassCastException.
553	+	*
554		* @param tasks the array of tasks
555		* @throws NullPointerException if tasks or any element are null
556		* @throws RuntimeException or Error if any task did so
#	Line 592 | Line 594 | public abstract class ForkJoinTask<V> im
594		* encounters an exception, others may be cancelled.  This method
595		* may be invoked only from within ForkJoinTask computations (as
596		* may be determined using method {@link
597	<	* #inForkJoinPool}). Attempts to invoke in other contexts resul!t
598	<	* in exceptions or errors possibly including ClassCastException.
597	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
598	>	* in exceptions or errors, possibly including ClassCastException.
599		*
600		* @param tasks the collection of tasks
601		* @throws NullPointerException if tasks or any element are null
602		* @throws RuntimeException or Error if any task did so
603		*/
604		public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) {
605	<	if (!(tasks instanceof List)) {
606	<	invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()]));
605	>	if (!(tasks instanceof List<?>)) {
606	>	invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()]));
607		return;
608		}
609	+	@SuppressWarnings("unchecked")
610		List<? extends ForkJoinTask<?>> ts =
611	<	(List<? extends ForkJoinTask<?>>)tasks;
611	>	(List<? extends ForkJoinTask<?>>) tasks;
612		Throwable ex = null;
613		int last = ts.size() - 1;
614		for (int i = last; i >= 0; --i) {
#	Line 680 | Line 683 | public abstract class ForkJoinTask<V> im
683		*
684		* @param mayInterruptIfRunning this value is ignored in the
685		* default implementation because tasks are not in general
686	<	* cancelled via interruption.
686	>	* cancelled via interruption
687		*
688		* @return true if this task is now cancelled
689		*/
#	Line 730 | Line 733 | public abstract class ForkJoinTask<V> im
733		*/
734		public void completeExceptionally(Throwable ex) {
735		setDoneExceptionally((ex instanceof RuntimeException) ||
736	<	(ex instanceof Error)? ex :
736	>	(ex instanceof Error) ? ex :
737		new RuntimeException(ex));
738		}
739
#	Line 749 | Line 752 | public abstract class ForkJoinTask<V> im
752		public void complete(V value) {
753		try {
754		setRawResult(value);
755	<	} catch(Throwable rex) {
755	>	} catch (Throwable rex) {
756		setDoneExceptionally(rex);
757		return;
758		}
#	Line 781 | Line 784 | public abstract class ForkJoinTask<V> im
784		* tasks). This method may be invoked only from within
785		* ForkJoinTask computations (as may be determined using method
786		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
787	<	* resul!t in exceptions or errors possibly including
787	>	* result in exceptions or errors, possibly including
788		* ClassCastException.
789		*
790		* @return the computed result
791		*/
792		public final V helpJoin() {
793	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread());
793	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread();
794		if (status < 0 || !w.unpushTask(this) || !tryExec())
795		reportException(busyJoin(w));
796		return getRawResult();
#	Line 797 | Line 800 | public abstract class ForkJoinTask<V> im
800		* Possibly executes other tasks until this task is ready.  This
801		* method may be invoked only from within ForkJoinTask
802		* computations (as may be determined using method {@link
803	<	* #inForkJoinPool}). Attempts to invoke in other contexts resul!t
804	<	* in exceptions or errors possibly including ClassCastException.
803	>	* #inForkJoinPool}). Attempts to invoke in other contexts result
804	>	* in exceptions or errors, possibly including ClassCastException.
805		*/
806		public final void quietlyHelpJoin() {
807		if (status >= 0) {
808		ForkJoinWorkerThread w =
809	<	(ForkJoinWorkerThread)(Thread.currentThread());
809	>	(ForkJoinWorkerThread) Thread.currentThread();
810		if (!w.unpushTask(this) || !tryQuietlyInvoke())
811		busyJoin(w);
812		}
#	Line 842 | Line 845 | public abstract class ForkJoinTask<V> im
845		* joined, instead executing them until all are processed.
846		*/
847		public static void helpQuiesce() {
848	<	((ForkJoinWorkerThread)(Thread.currentThread())).
849	<	helpQuiescePool();
848	>	((ForkJoinWorkerThread) Thread.currentThread())
849	>	.helpQuiescePool();
850		}
851
852		/**
#	Line 866 | Line 869 | public abstract class ForkJoinTask<V> im
869		* Returns the pool hosting the current task execution, or null
870		* if this task is executing outside of any ForkJoinPool.
871		*
872	<	* @return the pool, or null if none.
872	>	* @return the pool, or null if none
873		*/
874		public static ForkJoinPool getPool() {
875		Thread t = Thread.currentThread();
876	<	return ((t instanceof ForkJoinWorkerThread)?
877	<	((ForkJoinWorkerThread)t).pool : null);
876	>	return (t instanceof ForkJoinWorkerThread) ?
877	>	((ForkJoinWorkerThread) t).pool : null;
878		}
879
880		/**
881	<	* Returns true if the current thread is executing as a
881	>	* Returns {@code true} if the current thread is executing as a
882		* ForkJoinPool computation.
883	<	* @return <code>true</code> if the current thread is executing as a
883	>	*
884	>	* @return {@code true} if the current thread is executing as a
885		* ForkJoinPool computation, or false otherwise
886		*/
887		public static boolean inForkJoinPool() {
#	Line 893 | Line 897 | public abstract class ForkJoinTask<V> im
897		* were not, stolen. This method may be invoked only from within
898		* ForkJoinTask computations (as may be determined using method
899		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
900	<	* result in exceptions or errors possibly including
900	>	* result in exceptions or errors, possibly including
901		* ClassCastException.
902		*
903		* @return true if unforked
904		*/
905		public boolean tryUnfork() {
906	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).unpushTask(this);
906	>	return ((ForkJoinWorkerThread) Thread.currentThread())
907	>	.unpushTask(this);
908		}
909
910		/**
#	Line 911 | Line 916 | public abstract class ForkJoinTask<V> im
916		* @return the number of tasks
917		*/
918		public static int getQueuedTaskCount() {
919	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
920	<	getQueueSize();
919	>	return ((ForkJoinWorkerThread) Thread.currentThread())
920	>	.getQueueSize();
921		}
922
923		/**
#	Line 928 | Line 933 | public abstract class ForkJoinTask<V> im
933		* @return the surplus number of tasks, which may be negative
934		*/
935		public static int getSurplusQueuedTaskCount() {
936	<	return ((ForkJoinWorkerThread)(Thread.currentThread()))
936	>	return ((ForkJoinWorkerThread) Thread.currentThread())
937		.getEstimatedSurplusTaskCount();
938		}
939
#	Line 977 | Line 982 | public abstract class ForkJoinTask<V> im
982		* This method may be invoked only from within ForkJoinTask
983		* computations (as may be determined using method {@link
984		* #inForkJoinPool}). Attempts to invoke in other contexts result
985	<	* in exceptions or errors possibly including ClassCastException.
985	>	* in exceptions or errors, possibly including ClassCastException.
986		*
987		* @return the next task, or null if none are available
988		*/
989		protected static ForkJoinTask<?> peekNextLocalTask() {
990	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).peekTask();
990	>	return ((ForkJoinWorkerThread) Thread.currentThread())
991	>	.peekTask();
992		}
993
994		/**
#	Line 992 | Line 998 | public abstract class ForkJoinTask<V> im
998		* be useful otherwise.  This method may be invoked only from
999		* within ForkJoinTask computations (as may be determined using
1000		* method {@link #inForkJoinPool}). Attempts to invoke in other
1001	<	* contexts result in exceptions or errors possibly including
1001	>	* contexts result in exceptions or errors, possibly including
1002		* ClassCastException.
1003		*
1004		* @return the next task, or null if none are available
1005		*/
1006		protected static ForkJoinTask<?> pollNextLocalTask() {
1007	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).pollLocalTask();
1007	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1008	>	.pollLocalTask();
1009		}
1010
1011		/**
#	Line 1012 | Line 1019 | public abstract class ForkJoinTask<V> im
1019		* otherwise.  This method may be invoked only from within
1020		* ForkJoinTask computations (as may be determined using method
1021		* {@link #inForkJoinPool}). Attempts to invoke in other contexts
1022	<	* result in exceptions or errors possibly including
1022	>	* result in exceptions or errors, possibly including
1023		* ClassCastException.
1024		*
1025		* @return a task, or null if none are available
1026		*/
1027		protected static ForkJoinTask<?> pollTask() {
1028	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
1029	<	pollTask();
1028	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1029	>	.pollTask();
1030		}
1031
1032		// Serialization support
#	Line 1051 | Line 1058 | public abstract class ForkJoinTask<V> im
1058		status |= EXTERNAL_SIGNAL; // conservatively set external signal
1059		Object ex = s.readObject();
1060		if (ex != null)
1061	<	setDoneExceptionally((Throwable)ex);
1061	>	setDoneExceptionally((Throwable) ex);
1062		}
1063
1064	<	// Temporary Unsafe mechanics for preliminary release
1065	<	private static Unsafe getUnsafe() throws Throwable {
1064	>	// Unsafe mechanics for jsr166y 3rd party package.
1065	>	private static sun.misc.Unsafe getUnsafe() {
1066		try {
1067	<	return Unsafe.getUnsafe();
1067	>	return sun.misc.Unsafe.getUnsafe();
1068		} catch (SecurityException se) {
1069		try {
1070		return java.security.AccessController.doPrivileged
1071	<	(new java.security.PrivilegedExceptionAction<Unsafe>() {
1072	<	public Unsafe run() throws Exception {
1073	<	return getUnsafePrivileged();
1071	>	(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1072	>	public sun.misc.Unsafe run() throws Exception {
1073	>	return getUnsafeByReflection();
1074		}});
1075		} catch (java.security.PrivilegedActionException e) {
1076	<	throw e.getCause();
1076	>	throw new RuntimeException("Could not initialize intrinsics",
1077	>	e.getCause());
1078		}
1079		}
1080		}
1081
1082	<	private static Unsafe getUnsafePrivileged()
1082	>	private static sun.misc.Unsafe getUnsafeByReflection()
1083		throws NoSuchFieldException, IllegalAccessException {
1084	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1084	>	java.lang.reflect.Field f =
1085	>	sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
1086		f.setAccessible(true);
1087	<	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));
1087	>	return (sun.misc.Unsafe) f.get(null);
1088		}
1089
1090	<	static final Unsafe UNSAFE;
1088	<	static final long statusOffset;
1089	<
1090	<	static {
1090	>	private static long fieldOffset(String fieldName, Class<?> klazz) {
1091		try {
1092	<	UNSAFE = getUnsafe();
1093	<	statusOffset = fieldOffset("status");
1094	<	} catch (Throwable e) {
1095	<	throw new RuntimeException("Could not initialize intrinsics", e);
1092	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName));
1093	>	} catch (NoSuchFieldException e) {
1094	>	// Convert Exception to Error
1095	>	NoSuchFieldError error = new NoSuchFieldError(fieldName);
1096	>	error.initCause(e);
1097	>	throw error;
1098		}
1099		}
1100
1101	+	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1102	+	static final long statusOffset =
1103	+	fieldOffset("status", ForkJoinTask.class);
1104	+
1105		}

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