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 |
109 |
|
* in general sensible to serialize tasks only before or after, but |
110 |
|
* not during execution. Serialization is not relied on during |
111 |
|
* execution itself. |
112 |
+ |
* |
113 |
+ |
* @since 1.7 |
114 |
+ |
* @author Doug Lea |
115 |
|
*/ |
116 |
|
public abstract class ForkJoinTask<V> implements Future<V>, Serializable { |
117 |
|
|
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) { |
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 |
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. |
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(); |
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) |
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); |
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 |
|
} |
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 { |
432 |
|
try { |
433 |
|
if (!exec()) |
434 |
|
return; |
435 |
< |
} catch(Throwable rex) { |
435 |
> |
} catch (Throwable rex) { |
436 |
|
setDoneExceptionally(rex); |
437 |
|
return; |
438 |
|
} |
464 |
|
final void cancelIgnoringExceptions() { |
465 |
|
try { |
466 |
|
cancel(false); |
467 |
< |
} catch(Throwable ignore) { |
467 |
> |
} catch (Throwable ignore) { |
468 |
|
} |
469 |
|
} |
470 |
|
|
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 |
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 |
|
/** |
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 |
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 |
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 |
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) { |
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 |
|
*/ |
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 |
|
|
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 |
|
} |
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(); |
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 |
|
} |
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 |
|
/** |
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 |
|
/** |
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 |
|
/** |
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 |
|
/** |
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 |
|
|
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 |
|
/** |
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 |
|
/** |
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 |
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 |