5 |
|
*/ |
6 |
|
|
7 |
|
package jsr166y; |
8 |
+ |
|
9 |
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import java.io.Serializable; |
10 |
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import java.util.Collection; |
11 |
|
import java.util.List; |
71 |
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* but doing do requires three further considerations: (1) Completion |
72 |
|
* of few if any <em>other</em> tasks should be dependent on a task |
73 |
|
* that blocks on external synchronization or IO. Event-style async |
74 |
< |
* tasks that are never joined often fall into this category. (2) To |
75 |
< |
* minimize resource impact, tasks should be small; ideally performing |
76 |
< |
* only the (possibly) blocking action. (3) Unless the {@link |
74 |
> |
* tasks that are never joined (for example, those subclassing {@link |
75 |
> |
* CountedCompleter}) often fall into this category. (2) To minimize |
76 |
> |
* resource impact, tasks should be small; ideally performing only the |
77 |
> |
* (possibly) blocking action. (3) Unless the {@link |
78 |
|
* ForkJoinPool.ManagedBlocker} API is used, or the number of possibly |
79 |
|
* blocked tasks is known to be less than the pool's {@link |
80 |
|
* ForkJoinPool#getParallelism} level, the pool cannot guarantee that |
117 |
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* <p>The ForkJoinTask class is not usually directly subclassed. |
118 |
|
* Instead, you subclass one of the abstract classes that support a |
119 |
|
* particular style of fork/join processing, typically {@link |
120 |
< |
* RecursiveAction} for computations that do not return results, or |
121 |
< |
* {@link RecursiveTask} for those that do. Normally, a concrete |
122 |
< |
* ForkJoinTask subclass declares fields comprising its parameters, |
123 |
< |
* established in a constructor, and then defines a {@code compute} |
124 |
< |
* method that somehow uses the control methods supplied by this base |
125 |
< |
* class. While these methods have {@code public} access (to allow |
126 |
< |
* instances of different task subclasses to call each other's |
127 |
< |
* methods), some of them may only be called from within other |
128 |
< |
* ForkJoinTasks (as may be determined using method {@link |
129 |
< |
* #inForkJoinPool}). Attempts to invoke them in other contexts |
130 |
< |
* result in exceptions or errors, possibly including |
131 |
< |
* {@code ClassCastException}. |
120 |
> |
* RecursiveAction} for most computations that do not return results, |
121 |
> |
* {@link RecursiveTask} for those that do, and {@link |
122 |
> |
* CountedCompleter} for those in which completed actions trigger |
123 |
> |
* other actions. Normally, a concrete ForkJoinTask subclass declares |
124 |
> |
* fields comprising its parameters, established in a constructor, and |
125 |
> |
* then defines a {@code compute} method that somehow uses the control |
126 |
> |
* methods supplied by this base class. While these methods have |
127 |
> |
* {@code public} access (to allow instances of different task |
128 |
> |
* subclasses to call each other's methods), some of them may only be |
129 |
> |
* called from within other ForkJoinTasks (as may be determined using |
130 |
> |
* method {@link #inForkJoinPool}). Attempts to invoke them in other |
131 |
> |
* contexts result in exceptions or errors, possibly including {@code |
132 |
> |
* ClassCastException}. |
133 |
|
* |
134 |
|
* <p>Method {@link #join} and its variants are appropriate for use |
135 |
|
* only when completion dependencies are acyclic; that is, the |
140 |
|
* {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that |
141 |
|
* may be of use in constructing custom subclasses for problems that |
142 |
|
* are not statically structured as DAGs. To support such usages a |
143 |
< |
* ForkJoinTask may be atomically <em>marked</em> using {@link |
144 |
< |
* #markForkJoinTask} and checked for marking using {@link |
145 |
< |
* #isMarkedForkJoinTask}. The ForkJoinTask implementation does not |
146 |
< |
* use these {@code protected} methods or marks for any purpose, but |
147 |
< |
* they may be of use in the construction of specialized subclasses. |
148 |
< |
* For example, parallel graph traversals can use the supplied methods |
149 |
< |
* to avoid revisiting nodes/tasks that have already been processed. |
150 |
< |
* Also, completion based designs can use them to record that one |
151 |
< |
* subtask has completed. (Method names for marking are bulky in part |
152 |
< |
* to encourage definition of methods that reflect their usage |
150 |
< |
* patterns.) |
143 |
> |
* ForkJoinTask may be atomically <em>tagged</em> with a {@code short} |
144 |
> |
* value using {@link #setForkJoinTaskTag} or {@link |
145 |
> |
* #compareAndSetForkJoinTaskTag} and checked using {@link |
146 |
> |
* #getForkJoinTaskTag}. The ForkJoinTask implementation does not use |
147 |
> |
* these {@code protected} methods or tags for any purpose, but they |
148 |
> |
* may be of use in the construction of specialized subclasses. For |
149 |
> |
* example, parallel graph traversals can use the supplied methods to |
150 |
> |
* avoid revisiting nodes/tasks that have already been processed. |
151 |
> |
* (Method names for tagging are bulky in part to encourage definition |
152 |
> |
* of methods that reflect their usage patterns.) |
153 |
|
* |
154 |
|
* <p>Most base support methods are {@code final}, to prevent |
155 |
|
* overriding of implementations that are intrinsically tied to the |
199 |
|
* methods in a way that flows well in javadocs. |
200 |
|
*/ |
201 |
|
|
200 |
– |
/** |
201 |
– |
* The number of times to try to help join a task without any |
202 |
– |
* apparent progress before giving up and blocking. The value is |
203 |
– |
* arbitrary but should be large enough to cope with transient |
204 |
– |
* stalls (due to GC etc) that can cause helping methods not to be |
205 |
– |
* able to proceed because other workers have not progressed to |
206 |
– |
* the point where subtasks can be found or taken. |
207 |
– |
*/ |
208 |
– |
private static final int HELP_RETRIES = 32; |
209 |
– |
|
202 |
|
/* |
203 |
|
* The status field holds run control status bits packed into a |
204 |
|
* single int to minimize footprint and to ensure atomicity (via |
205 |
|
* CAS). Status is initially zero, and takes on nonnegative |
206 |
< |
* values until completed, upon which status holds value |
207 |
< |
* NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking |
208 |
< |
* waits by other threads have the SIGNAL bit set. Completion of |
209 |
< |
* a stolen task with SIGNAL set awakens any waiters via |
210 |
< |
* notifyAll. Even though suboptimal for some purposes, we use |
211 |
< |
* basic builtin wait/notify to take advantage of "monitor |
212 |
< |
* inflation" in JVMs that we would otherwise need to emulate to |
213 |
< |
* avoid adding further per-task bookkeeping overhead. We want |
214 |
< |
* these monitors to be "fat", i.e., not use biasing or thin-lock |
215 |
< |
* techniques, so use some odd coding idioms that tend to avoid |
216 |
< |
* them. |
206 |
> |
* values until completed, upon which status (anded with |
207 |
> |
* DONE_MASK) holds value NORMAL, CANCELLED, or EXCEPTIONAL. Tasks |
208 |
> |
* undergoing blocking waits by other threads have the SIGNAL bit |
209 |
> |
* set. Completion of a stolen task with SIGNAL set awakens any |
210 |
> |
* waiters via notifyAll. Even though suboptimal for some |
211 |
> |
* purposes, we use basic builtin wait/notify to take advantage of |
212 |
> |
* "monitor inflation" in JVMs that we would otherwise need to |
213 |
> |
* emulate to avoid adding further per-task bookkeeping overhead. |
214 |
> |
* We want these monitors to be "fat", i.e., not use biasing or |
215 |
> |
* thin-lock techniques, so use some odd coding idioms that tend |
216 |
> |
* to avoid them, mainly by arranging that every synchronized |
217 |
> |
* block performs a wait, notifyAll or both. |
218 |
> |
* |
219 |
> |
* These control bits occupy only (some of) the upper half (16 |
220 |
> |
* bits) of status field. The lower bits are used for user-defined |
221 |
> |
* tags. |
222 |
|
*/ |
223 |
|
|
224 |
|
/** The run status of this task */ |
225 |
|
volatile int status; // accessed directly by pool and workers |
226 |
< |
static final int NORMAL = 0xfffffffc; // negative with low 2 bits 0 |
227 |
< |
static final int CANCELLED = 0xfffffff8; // must be < NORMAL |
228 |
< |
static final int EXCEPTIONAL = 0xfffffff4; // must be < CANCELLED |
229 |
< |
static final int SIGNAL = 0x00000001; |
230 |
< |
static final int MARKED = 0x00000002; |
226 |
> |
static final int DONE_MASK = 0xf0000000; // mask out non-completion bits |
227 |
> |
static final int NORMAL = 0xf0000000; // must be negative |
228 |
> |
static final int CANCELLED = 0xc0000000; // must be < NORMAL |
229 |
> |
static final int EXCEPTIONAL = 0x80000000; // must be < CANCELLED |
230 |
> |
static final int SIGNAL = 0x00010000; // must be >= 1 << 16 |
231 |
> |
static final int SMASK = 0x0000ffff; // short bits for tags |
232 |
|
|
233 |
|
/** |
234 |
|
* Marks completion and wakes up threads waiting to join this |
235 |
< |
* task, also clearing signal request bits. A specialization for |
238 |
< |
* NORMAL completion is in method doExec. |
235 |
> |
* task. |
236 |
|
* |
237 |
|
* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL |
238 |
|
* @return completion status on exit |
241 |
|
for (int s;;) { |
242 |
|
if ((s = status) < 0) |
243 |
|
return s; |
244 |
< |
if (U.compareAndSwapInt(this, STATUS, s, (s & ~SIGNAL)|completion)) { |
245 |
< |
if ((s & SIGNAL) != 0) |
244 |
> |
if (U.compareAndSwapInt(this, STATUS, s, s | completion)) { |
245 |
> |
if ((s >>> 16) != 0) |
246 |
|
synchronized (this) { notifyAll(); } |
247 |
|
return completion; |
248 |
|
} |
264 |
|
} catch (Throwable rex) { |
265 |
|
return setExceptionalCompletion(rex); |
266 |
|
} |
267 |
< |
while ((s = status) >= 0 && completed) { |
268 |
< |
if (U.compareAndSwapInt(this, STATUS, s, (s & ~SIGNAL)|NORMAL)) { |
272 |
< |
if ((s & SIGNAL) != 0) |
273 |
< |
synchronized (this) { notifyAll(); } |
274 |
< |
return NORMAL; |
275 |
< |
} |
276 |
< |
} |
267 |
> |
if (completed) |
268 |
> |
s = setCompletion(NORMAL); |
269 |
|
} |
270 |
|
return s; |
271 |
|
} |
272 |
|
|
273 |
|
/** |
274 |
+ |
* Tries to set SIGNAL status unless already completed. Used by |
275 |
+ |
* ForkJoinPool. Other variants are directly incorporated into |
276 |
+ |
* externalAwaitDone etc. |
277 |
+ |
* |
278 |
+ |
* @return true if successful |
279 |
+ |
*/ |
280 |
+ |
final boolean trySetSignal() { |
281 |
+ |
int s = status; |
282 |
+ |
return s >= 0 && U.compareAndSwapInt(this, STATUS, s, s | SIGNAL); |
283 |
+ |
} |
284 |
+ |
|
285 |
+ |
/** |
286 |
|
* Blocks a non-worker-thread until completion. |
287 |
|
* @return status upon completion |
288 |
|
*/ |
289 |
|
private int externalAwaitDone() { |
290 |
+ |
boolean interrupted = false; |
291 |
|
int s; |
292 |
< |
if ((s = status) >= 0) { |
293 |
< |
boolean interrupted = false; |
294 |
< |
synchronized (this) { |
295 |
< |
while ((s = status) >= 0) { |
291 |
< |
if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { |
292 |
> |
while ((s = status) >= 0) { |
293 |
> |
if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { |
294 |
> |
synchronized (this) { |
295 |
> |
if (status >= 0) { |
296 |
|
try { |
297 |
|
wait(); |
298 |
|
} catch (InterruptedException ie) { |
299 |
|
interrupted = true; |
300 |
|
} |
301 |
|
} |
302 |
+ |
else |
303 |
+ |
notifyAll(); |
304 |
|
} |
305 |
|
} |
300 |
– |
if (interrupted) |
301 |
– |
Thread.currentThread().interrupt(); |
306 |
|
} |
307 |
+ |
if (interrupted) |
308 |
+ |
Thread.currentThread().interrupt(); |
309 |
|
return s; |
310 |
|
} |
311 |
|
|
312 |
|
/** |
313 |
< |
* Blocks a non-worker-thread until completion or interruption or timeout. |
313 |
> |
* Blocks a non-worker-thread until completion or interruption. |
314 |
|
*/ |
315 |
< |
private int externalInterruptibleAwaitDone(long millis) |
310 |
< |
throws InterruptedException { |
315 |
> |
private int externalInterruptibleAwaitDone() throws InterruptedException { |
316 |
|
int s; |
317 |
|
if (Thread.interrupted()) |
318 |
|
throw new InterruptedException(); |
319 |
< |
if ((s = status) >= 0) { |
320 |
< |
synchronized (this) { |
321 |
< |
while ((s = status) >= 0) { |
322 |
< |
if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { |
323 |
< |
wait(millis); |
324 |
< |
if (millis > 0L) |
325 |
< |
break; |
321 |
< |
} |
319 |
> |
while ((s = status) >= 0) { |
320 |
> |
if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { |
321 |
> |
synchronized (this) { |
322 |
> |
if (status >= 0) |
323 |
> |
wait(); |
324 |
> |
else |
325 |
> |
notifyAll(); |
326 |
|
} |
327 |
|
} |
328 |
|
} |
329 |
|
return s; |
330 |
|
} |
331 |
|
|
328 |
– |
|
332 |
|
/** |
333 |
|
* Implementation for join, get, quietlyJoin. Directly handles |
334 |
|
* only cases of already-completed, external wait, and |
335 |
< |
* unfork+exec. Others are relayed to awaitJoin. |
335 |
> |
* unfork+exec. Others are relayed to ForkJoinPool.awaitJoin. |
336 |
|
* |
337 |
|
* @return status upon completion |
338 |
|
*/ |
339 |
|
private int doJoin() { |
340 |
|
int s; Thread t; ForkJoinWorkerThread wt; ForkJoinPool.WorkQueue w; |
341 |
|
if ((s = status) >= 0) { |
342 |
< |
if (!((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) |
343 |
< |
s = externalAwaitDone(); |
344 |
< |
else if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue). |
345 |
< |
tryUnpush(this) || (s = doExec()) >= 0) |
343 |
< |
s = awaitJoin(w, wt.pool); |
344 |
< |
} |
345 |
< |
return s; |
346 |
< |
} |
347 |
< |
|
348 |
< |
/** |
349 |
< |
* Helps and/or blocks until joined. |
350 |
< |
* |
351 |
< |
* @param w the joiner |
352 |
< |
* @param p the pool |
353 |
< |
* @return status upon completion |
354 |
< |
*/ |
355 |
< |
private int awaitJoin(ForkJoinPool.WorkQueue w, ForkJoinPool p) { |
356 |
< |
int s; |
357 |
< |
ForkJoinTask<?> prevJoin = w.currentJoin; |
358 |
< |
w.currentJoin = this; |
359 |
< |
for (int k = HELP_RETRIES; (s = status) >= 0;) { |
360 |
< |
if ((w.queueSize() > 0) ? |
361 |
< |
w.tryRemoveAndExec(this) : // self-help |
362 |
< |
p.tryHelpStealer(w, this)) // help process tasks |
363 |
< |
k = HELP_RETRIES; // reset if made progress |
364 |
< |
else if ((s = status) < 0) // recheck |
365 |
< |
break; |
366 |
< |
else if (--k > 0) { |
367 |
< |
if ((k & 3) == 1) |
368 |
< |
Thread.yield(); // occasionally yield |
369 |
< |
} |
370 |
< |
else if (k == 0) |
371 |
< |
p.tryPollForAndExec(w, this); // uncommon self-help case |
372 |
< |
else if (p.tryCompensate()) { // true if can block |
373 |
< |
try { |
374 |
< |
int ss = status; |
375 |
< |
if (ss >= 0 && // assert need signal |
376 |
< |
U.compareAndSwapInt(this, STATUS, ss, ss | SIGNAL)) { |
377 |
< |
synchronized (this) { |
378 |
< |
if (status >= 0) // block |
379 |
< |
wait(); |
380 |
< |
} |
381 |
< |
} |
382 |
< |
} catch (InterruptedException ignore) { |
383 |
< |
} finally { |
384 |
< |
p.incrementActiveCount(); // re-activate |
385 |
< |
} |
342 |
> |
if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) { |
343 |
> |
if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue). |
344 |
> |
tryUnpush(this) || (s = doExec()) >= 0) |
345 |
> |
s = wt.pool.awaitJoin(w, this); |
346 |
|
} |
347 |
+ |
else |
348 |
+ |
s = externalAwaitDone(); |
349 |
|
} |
388 |
– |
w.currentJoin = prevJoin; |
350 |
|
return s; |
351 |
|
} |
352 |
|
|
356 |
|
* @return status upon completion |
357 |
|
*/ |
358 |
|
private int doInvoke() { |
359 |
< |
int s; Thread t; |
359 |
> |
int s; Thread t; ForkJoinWorkerThread wt; |
360 |
|
if ((s = doExec()) >= 0) { |
361 |
< |
if (!((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) |
361 |
> |
if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) |
362 |
> |
s = (wt = (ForkJoinWorkerThread)t).pool.awaitJoin(wt.workQueue, |
363 |
> |
this); |
364 |
> |
else |
365 |
|
s = externalAwaitDone(); |
402 |
– |
else { |
403 |
– |
ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t; |
404 |
– |
s = awaitJoin(wt.workQueue, wt.pool); |
405 |
– |
} |
366 |
|
} |
367 |
|
return s; |
368 |
|
} |
399 |
|
* any ForkJoinPool will call helpExpungeStaleExceptions when its |
400 |
|
* pool becomes isQuiescent. |
401 |
|
*/ |
402 |
< |
static final class ExceptionNode extends WeakReference<ForkJoinTask<?>>{ |
402 |
> |
static final class ExceptionNode extends WeakReference<ForkJoinTask<?>> { |
403 |
|
final Throwable ex; |
404 |
|
ExceptionNode next; |
405 |
|
final long thrower; // use id not ref to avoid weak cycles |
412 |
|
} |
413 |
|
|
414 |
|
/** |
415 |
< |
* Records exception and sets exceptional completion. |
415 |
> |
* Records exception and sets status. |
416 |
|
* |
417 |
|
* @return status on exit |
418 |
|
*/ |
419 |
< |
private int setExceptionalCompletion(Throwable ex) { |
420 |
< |
int h = System.identityHashCode(this); |
421 |
< |
final ReentrantLock lock = exceptionTableLock; |
422 |
< |
lock.lock(); |
423 |
< |
try { |
424 |
< |
expungeStaleExceptions(); |
425 |
< |
ExceptionNode[] t = exceptionTable; |
426 |
< |
int i = h & (t.length - 1); |
427 |
< |
for (ExceptionNode e = t[i]; ; e = e.next) { |
428 |
< |
if (e == null) { |
429 |
< |
t[i] = new ExceptionNode(this, ex, t[i]); |
430 |
< |
break; |
419 |
> |
final int recordExceptionalCompletion(Throwable ex) { |
420 |
> |
int s; |
421 |
> |
if ((s = status) >= 0) { |
422 |
> |
int h = System.identityHashCode(this); |
423 |
> |
final ReentrantLock lock = exceptionTableLock; |
424 |
> |
lock.lock(); |
425 |
> |
try { |
426 |
> |
expungeStaleExceptions(); |
427 |
> |
ExceptionNode[] t = exceptionTable; |
428 |
> |
int i = h & (t.length - 1); |
429 |
> |
for (ExceptionNode e = t[i]; ; e = e.next) { |
430 |
> |
if (e == null) { |
431 |
> |
t[i] = new ExceptionNode(this, ex, t[i]); |
432 |
> |
break; |
433 |
> |
} |
434 |
> |
if (e.get() == this) // already present |
435 |
> |
break; |
436 |
|
} |
437 |
< |
if (e.get() == this) // already present |
438 |
< |
break; |
437 |
> |
} finally { |
438 |
> |
lock.unlock(); |
439 |
|
} |
440 |
< |
} finally { |
476 |
< |
lock.unlock(); |
440 |
> |
s = setCompletion(EXCEPTIONAL); |
441 |
|
} |
442 |
< |
return setCompletion(EXCEPTIONAL); |
442 |
> |
return s; |
443 |
> |
} |
444 |
> |
|
445 |
> |
/** |
446 |
> |
* Records exception and possibly propagates |
447 |
> |
* |
448 |
> |
* @return status on exit |
449 |
> |
*/ |
450 |
> |
private int setExceptionalCompletion(Throwable ex) { |
451 |
> |
int s = recordExceptionalCompletion(ex); |
452 |
> |
if ((s & DONE_MASK) == EXCEPTIONAL) |
453 |
> |
internalPropagateException(ex); |
454 |
> |
return s; |
455 |
> |
} |
456 |
> |
|
457 |
> |
/** |
458 |
> |
* Hook for exception propagation support for tasks with completers. |
459 |
> |
*/ |
460 |
> |
void internalPropagateException(Throwable ex) { |
461 |
|
} |
462 |
|
|
463 |
|
/** |
521 |
|
* @return the exception, or null if none |
522 |
|
*/ |
523 |
|
private Throwable getThrowableException() { |
524 |
< |
if (status != EXCEPTIONAL) |
524 |
> |
if ((status & DONE_MASK) != EXCEPTIONAL) |
525 |
|
return null; |
526 |
|
int h = System.identityHashCode(this); |
527 |
|
ExceptionNode e; |
539 |
|
Throwable ex; |
540 |
|
if (e == null || (ex = e.ex) == null) |
541 |
|
return null; |
542 |
< |
if (e.thrower != Thread.currentThread().getId()) { |
542 |
> |
if (false && e.thrower != Thread.currentThread().getId()) { |
543 |
|
Class<? extends Throwable> ec = ex.getClass(); |
544 |
|
try { |
545 |
|
Constructor<?> noArgCtor = null; |
606 |
|
} |
607 |
|
|
608 |
|
/** |
609 |
< |
* Report the result of invoke or join; called only upon |
628 |
< |
* non-normal return of internal versions. |
609 |
> |
* Throws exception, if any, associated with the given status. |
610 |
|
*/ |
611 |
< |
private V reportResult() { |
612 |
< |
int s; Throwable ex; |
613 |
< |
if ((s = status) == CANCELLED) |
614 |
< |
throw new CancellationException(); |
615 |
< |
if (s == EXCEPTIONAL && (ex = getThrowableException()) != null) |
611 |
> |
private void reportException(int s) { |
612 |
> |
Throwable ex = ((s == CANCELLED) ? new CancellationException() : |
613 |
> |
(s == EXCEPTIONAL) ? getThrowableException() : |
614 |
> |
null); |
615 |
> |
if (ex != null) |
616 |
|
U.throwException(ex); |
636 |
– |
return getRawResult(); |
617 |
|
} |
618 |
|
|
619 |
|
// public methods |
637 |
|
* @return {@code this}, to simplify usage |
638 |
|
*/ |
639 |
|
public final ForkJoinTask<V> fork() { |
640 |
< |
ForkJoinWorkerThread wt; |
661 |
< |
(wt = (ForkJoinWorkerThread)Thread.currentThread()). |
662 |
< |
workQueue.push(this, wt.pool); |
640 |
> |
((ForkJoinWorkerThread)Thread.currentThread()).workQueue.push(this); |
641 |
|
return this; |
642 |
|
} |
643 |
|
|
653 |
|
* @return the computed result |
654 |
|
*/ |
655 |
|
public final V join() { |
656 |
< |
if (doJoin() != NORMAL) |
657 |
< |
return reportResult(); |
658 |
< |
else |
659 |
< |
return getRawResult(); |
656 |
> |
int s; |
657 |
> |
if ((s = doJoin() & DONE_MASK) != NORMAL) |
658 |
> |
reportException(s); |
659 |
> |
return getRawResult(); |
660 |
|
} |
661 |
|
|
662 |
|
/** |
668 |
|
* @return the computed result |
669 |
|
*/ |
670 |
|
public final V invoke() { |
671 |
< |
if (doInvoke() != NORMAL) |
672 |
< |
return reportResult(); |
673 |
< |
else |
674 |
< |
return getRawResult(); |
671 |
> |
int s; |
672 |
> |
if ((s = doInvoke() & DONE_MASK) != NORMAL) |
673 |
> |
reportException(s); |
674 |
> |
return getRawResult(); |
675 |
|
} |
676 |
|
|
677 |
|
/** |
698 |
|
* @throws NullPointerException if any task is null |
699 |
|
*/ |
700 |
|
public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) { |
701 |
+ |
int s1, s2; |
702 |
|
t2.fork(); |
703 |
< |
t1.invoke(); |
704 |
< |
t2.join(); |
703 |
> |
if ((s1 = t1.doInvoke() & DONE_MASK) != NORMAL) |
704 |
> |
t1.reportException(s1); |
705 |
> |
if ((s2 = t2.doJoin() & DONE_MASK) != NORMAL) |
706 |
> |
t2.reportException(s2); |
707 |
|
} |
708 |
|
|
709 |
|
/** |
840 |
|
* @return {@code true} if this task is now cancelled |
841 |
|
*/ |
842 |
|
public boolean cancel(boolean mayInterruptIfRunning) { |
843 |
< |
return setCompletion(CANCELLED) == CANCELLED; |
843 |
> |
return (setCompletion(CANCELLED) & DONE_MASK) == CANCELLED; |
844 |
|
} |
845 |
|
|
846 |
|
public final boolean isDone() { |
848 |
|
} |
849 |
|
|
850 |
|
public final boolean isCancelled() { |
851 |
< |
return status == CANCELLED; |
851 |
> |
return (status & DONE_MASK) == CANCELLED; |
852 |
|
} |
853 |
|
|
854 |
|
/** |
868 |
|
* exception and was not cancelled |
869 |
|
*/ |
870 |
|
public final boolean isCompletedNormally() { |
871 |
< |
return status == NORMAL; |
871 |
> |
return (status & DONE_MASK) == NORMAL; |
872 |
|
} |
873 |
|
|
874 |
|
/** |
879 |
|
* @return the exception, or {@code null} if none |
880 |
|
*/ |
881 |
|
public final Throwable getException() { |
882 |
< |
int s = status; |
882 |
> |
int s = status & DONE_MASK; |
883 |
|
return ((s >= NORMAL) ? null : |
884 |
|
(s == CANCELLED) ? new CancellationException() : |
885 |
|
getThrowableException()); |
929 |
|
} |
930 |
|
|
931 |
|
/** |
932 |
+ |
* Completes this task normally without setting a value. The most |
933 |
+ |
* recent value established by {@link #setRawResult} (or {@code |
934 |
+ |
* null} by default) will be returned as the result of subsequent |
935 |
+ |
* invocations of {@code join} and related operations. |
936 |
+ |
* |
937 |
+ |
* @since 1.8 |
938 |
+ |
*/ |
939 |
+ |
public final void quietlyComplete() { |
940 |
+ |
setCompletion(NORMAL); |
941 |
+ |
} |
942 |
+ |
|
943 |
+ |
/** |
944 |
|
* Waits if necessary for the computation to complete, and then |
945 |
|
* retrieves its result. |
946 |
|
* |
953 |
|
*/ |
954 |
|
public final V get() throws InterruptedException, ExecutionException { |
955 |
|
int s = (Thread.currentThread() instanceof ForkJoinWorkerThread) ? |
956 |
< |
doJoin() : externalInterruptibleAwaitDone(0L); |
956 |
> |
doJoin() : externalInterruptibleAwaitDone(); |
957 |
|
Throwable ex; |
958 |
< |
if (s == CANCELLED) |
958 |
> |
if ((s &= DONE_MASK) == CANCELLED) |
959 |
|
throw new CancellationException(); |
960 |
|
if (s == EXCEPTIONAL && (ex = getThrowableException()) != null) |
961 |
|
throw new ExecutionException(ex); |
978 |
|
*/ |
979 |
|
public final V get(long timeout, TimeUnit unit) |
980 |
|
throws InterruptedException, ExecutionException, TimeoutException { |
981 |
< |
// Messy in part because we measure in nanos, but wait in millis |
982 |
< |
int s; long millis, nanos; |
983 |
< |
Thread t = Thread.currentThread(); |
984 |
< |
if (!(t instanceof ForkJoinWorkerThread)) { |
985 |
< |
if ((millis = unit.toMillis(timeout)) > 0L) |
986 |
< |
s = externalInterruptibleAwaitDone(millis); |
987 |
< |
else |
988 |
< |
s = status; |
989 |
< |
} |
990 |
< |
else if ((s = status) >= 0 && (nanos = unit.toNanos(timeout)) > 0L) { |
991 |
< |
long deadline = System.nanoTime() + nanos; |
992 |
< |
ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t; |
993 |
< |
ForkJoinPool.WorkQueue w = wt.workQueue; |
994 |
< |
ForkJoinPool p = wt.pool; |
995 |
< |
if (w.tryUnpush(this)) |
996 |
< |
doExec(); |
997 |
< |
boolean blocking = false; |
981 |
> |
if (Thread.interrupted()) |
982 |
> |
throw new InterruptedException(); |
983 |
> |
// Messy in part because we measure in nanosecs, but wait in millisecs |
984 |
> |
int s; long ns, ms; |
985 |
> |
if ((s = status) >= 0 && (ns = unit.toNanos(timeout)) > 0L) { |
986 |
> |
long deadline = System.nanoTime() + ns; |
987 |
> |
ForkJoinPool p = null; |
988 |
> |
ForkJoinPool.WorkQueue w = null; |
989 |
> |
Thread t = Thread.currentThread(); |
990 |
> |
if (t instanceof ForkJoinWorkerThread) { |
991 |
> |
ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t; |
992 |
> |
p = wt.pool; |
993 |
> |
w = wt.workQueue; |
994 |
> |
s = p.helpJoinOnce(w, this); // no retries on failure |
995 |
> |
} |
996 |
> |
boolean canBlock = false; |
997 |
> |
boolean interrupted = false; |
998 |
|
try { |
999 |
|
while ((s = status) >= 0) { |
1000 |
< |
if (w.runState < 0) |
1000 |
> |
if (w != null && w.runState < 0) |
1001 |
|
cancelIgnoringExceptions(this); |
1002 |
< |
else if (!blocking) |
1003 |
< |
blocking = p.tryCompensate(); |
1002 |
> |
else if (!canBlock) { |
1003 |
> |
if (p == null || p.tryCompensate(this, null)) |
1004 |
> |
canBlock = true; |
1005 |
> |
} |
1006 |
|
else { |
1007 |
< |
millis = TimeUnit.NANOSECONDS.toMillis(nanos); |
1013 |
< |
if (millis > 0L && |
1007 |
> |
if ((ms = TimeUnit.NANOSECONDS.toMillis(ns)) > 0L && |
1008 |
|
U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { |
1009 |
< |
try { |
1010 |
< |
synchronized (this) { |
1011 |
< |
if (status >= 0) |
1012 |
< |
wait(millis); |
1009 |
> |
synchronized (this) { |
1010 |
> |
if (status >= 0) { |
1011 |
> |
try { |
1012 |
> |
wait(ms); |
1013 |
> |
} catch (InterruptedException ie) { |
1014 |
> |
if (p == null) |
1015 |
> |
interrupted = true; |
1016 |
> |
} |
1017 |
|
} |
1018 |
< |
} catch (InterruptedException ie) { |
1018 |
> |
else |
1019 |
> |
notifyAll(); |
1020 |
|
} |
1021 |
|
} |
1022 |
< |
if ((s = status) < 0 || |
1023 |
< |
(nanos = deadline - System.nanoTime()) <= 0L) |
1022 |
> |
if ((s = status) < 0 || interrupted || |
1023 |
> |
(ns = deadline - System.nanoTime()) <= 0L) |
1024 |
|
break; |
1025 |
|
} |
1026 |
|
} |
1027 |
|
} finally { |
1028 |
< |
if (blocking) |
1028 |
> |
if (p != null && canBlock) |
1029 |
|
p.incrementActiveCount(); |
1030 |
|
} |
1031 |
+ |
if (interrupted) |
1032 |
+ |
throw new InterruptedException(); |
1033 |
|
} |
1034 |
< |
if (s != NORMAL) { |
1034 |
> |
if ((s &= DONE_MASK) != NORMAL) { |
1035 |
|
Throwable ex; |
1036 |
|
if (s == CANCELLED) |
1037 |
|
throw new CancellationException(); |
1098 |
|
* setRawResult(null)}. |
1099 |
|
*/ |
1100 |
|
public void reinitialize() { |
1101 |
< |
if (status == EXCEPTIONAL) |
1101 |
> |
if ((status & DONE_MASK) == EXCEPTIONAL) |
1102 |
|
clearExceptionalCompletion(); |
1103 |
|
else |
1104 |
|
status = 0; |
1259 |
|
protected abstract void setRawResult(V value); |
1260 |
|
|
1261 |
|
/** |
1262 |
< |
* Immediately performs the base action of this task. This method |
1263 |
< |
* is designed to support extensions, and should not in general be |
1264 |
< |
* called otherwise. The return value controls whether this task |
1265 |
< |
* is considered to be done normally. It may return false in |
1262 |
> |
* Immediately performs the base action of this task and returns |
1263 |
> |
* true if, upon return from this method, this task is guaranteed |
1264 |
> |
* to have completed normally. This method may return false |
1265 |
> |
* otherwise, to indicate that this task is not necessarily |
1266 |
> |
* complete (or is not known to be complete), for example in |
1267 |
|
* asynchronous actions that require explicit invocations of |
1268 |
< |
* {@link #complete} to become joinable. It may also throw an |
1269 |
< |
* (unchecked) exception to indicate abnormal exit. |
1268 |
> |
* completion methods. This method may also throw an (unchecked) |
1269 |
> |
* exception to indicate abnormal exit. This method is designed to |
1270 |
> |
* support extensions, and should not in general be called |
1271 |
> |
* otherwise. |
1272 |
|
* |
1273 |
< |
* @return {@code true} if completed normally |
1273 |
> |
* @return {@code true} if this task is known to have completed normally |
1274 |
|
*/ |
1275 |
|
protected abstract boolean exec(); |
1276 |
|
|
1339 |
|
return wt.pool.nextTaskFor(wt.workQueue); |
1340 |
|
} |
1341 |
|
|
1342 |
< |
// Mark-bit operations |
1342 |
> |
// tag operations |
1343 |
|
|
1344 |
|
/** |
1345 |
< |
* Returns true if this task is marked. |
1345 |
> |
* Returns the tag for this task. |
1346 |
|
* |
1347 |
< |
* @return true if this task is marked |
1347 |
> |
* @return the tag for this task |
1348 |
|
* @since 1.8 |
1349 |
|
*/ |
1350 |
< |
public final boolean isMarkedForkJoinTask() { |
1351 |
< |
return (status & MARKED) != 0; |
1350 |
> |
public final short getForkJoinTaskTag() { |
1351 |
> |
return (short)status; |
1352 |
|
} |
1353 |
|
|
1354 |
|
/** |
1355 |
< |
* Atomically sets the mark on this task. |
1355 |
> |
* Atomically sets the tag value for this task. |
1356 |
|
* |
1357 |
< |
* @return true if this task was previously unmarked |
1357 |
> |
* @param tag the tag value |
1358 |
> |
* @return the previous value of the tag |
1359 |
|
* @since 1.8 |
1360 |
|
*/ |
1361 |
< |
public final boolean markForkJoinTask() { |
1361 |
> |
public final short setForkJoinTaskTag(short tag) { |
1362 |
|
for (int s;;) { |
1363 |
< |
if (((s = status) & MARKED) != 0) |
1364 |
< |
return false; |
1365 |
< |
if (U.compareAndSwapInt(this, STATUS, s, s | MARKED)) |
1361 |
< |
return true; |
1363 |
> |
if (U.compareAndSwapInt(this, STATUS, s = status, |
1364 |
> |
(s & ~SMASK) | (tag & SMASK))) |
1365 |
> |
return (short)s; |
1366 |
|
} |
1367 |
|
} |
1368 |
|
|
1369 |
|
/** |
1370 |
< |
* Atomically clears the mark on this task. |
1370 |
> |
* Atomically conditionally sets the tag value for this task. |
1371 |
> |
* Among other applications, tags can be used as visit markers |
1372 |
> |
* in tasks operating on graphs, as in methods that check: {@code |
1373 |
> |
* if (task.compareAndSetForkJoinTaskTag((short)0, (short)1))} |
1374 |
> |
* before processing, otherwise exiting because the node has |
1375 |
> |
* already been visited. |
1376 |
|
* |
1377 |
< |
* @return true if this task was previously marked |
1377 |
> |
* @param e the expected tag value |
1378 |
> |
* @param tag the new tag value |
1379 |
> |
* @return true if successful; i.e., the current value was |
1380 |
> |
* equal to e and is now tag. |
1381 |
|
* @since 1.8 |
1382 |
|
*/ |
1383 |
< |
public final boolean unmarkForkJoinTask() { |
1383 |
> |
public final boolean compareAndSetForkJoinTaskTag(short e, short tag) { |
1384 |
|
for (int s;;) { |
1385 |
< |
if (((s = status) & MARKED) == 0) |
1385 |
> |
if ((short)(s = status) != e) |
1386 |
|
return false; |
1387 |
< |
if (U.compareAndSwapInt(this, STATUS, s, s & ~MARKED)) |
1387 |
> |
if (U.compareAndSwapInt(this, STATUS, s, |
1388 |
> |
(s & ~SMASK) | (tag & SMASK))) |
1389 |
|
return true; |
1390 |
|
} |
1391 |
|
} |
1398 |
|
static final class AdaptedRunnable<T> extends ForkJoinTask<T> |
1399 |
|
implements RunnableFuture<T> { |
1400 |
|
final Runnable runnable; |
1388 |
– |
final T resultOnCompletion; |
1401 |
|
T result; |
1402 |
|
AdaptedRunnable(Runnable runnable, T result) { |
1403 |
|
if (runnable == null) throw new NullPointerException(); |
1404 |
|
this.runnable = runnable; |
1405 |
< |
this.resultOnCompletion = result; |
1405 |
> |
this.result = result; // OK to set this even before completion |
1406 |
|
} |
1407 |
< |
public T getRawResult() { return result; } |
1408 |
< |
public void setRawResult(T v) { result = v; } |
1409 |
< |
public boolean exec() { |
1410 |
< |
runnable.run(); |
1411 |
< |
result = resultOnCompletion; |
1412 |
< |
return true; |
1407 |
> |
public final T getRawResult() { return result; } |
1408 |
> |
public final void setRawResult(T v) { result = v; } |
1409 |
> |
public final boolean exec() { runnable.run(); return true; } |
1410 |
> |
public final void run() { invoke(); } |
1411 |
> |
private static final long serialVersionUID = 5232453952276885070L; |
1412 |
> |
} |
1413 |
> |
|
1414 |
> |
/** |
1415 |
> |
* Adaptor for Runnables without results |
1416 |
> |
*/ |
1417 |
> |
static final class AdaptedRunnableAction extends ForkJoinTask<Void> |
1418 |
> |
implements RunnableFuture<Void> { |
1419 |
> |
final Runnable runnable; |
1420 |
> |
AdaptedRunnableAction(Runnable runnable) { |
1421 |
> |
if (runnable == null) throw new NullPointerException(); |
1422 |
> |
this.runnable = runnable; |
1423 |
|
} |
1424 |
< |
public void run() { invoke(); } |
1424 |
> |
public final Void getRawResult() { return null; } |
1425 |
> |
public final void setRawResult(Void v) { } |
1426 |
> |
public final boolean exec() { runnable.run(); return true; } |
1427 |
> |
public final void run() { invoke(); } |
1428 |
|
private static final long serialVersionUID = 5232453952276885070L; |
1429 |
|
} |
1430 |
|
|
1439 |
|
if (callable == null) throw new NullPointerException(); |
1440 |
|
this.callable = callable; |
1441 |
|
} |
1442 |
< |
public T getRawResult() { return result; } |
1443 |
< |
public void setRawResult(T v) { result = v; } |
1444 |
< |
public boolean exec() { |
1442 |
> |
public final T getRawResult() { return result; } |
1443 |
> |
public final void setRawResult(T v) { result = v; } |
1444 |
> |
public final boolean exec() { |
1445 |
|
try { |
1446 |
|
result = callable.call(); |
1447 |
|
return true; |
1453 |
|
throw new RuntimeException(ex); |
1454 |
|
} |
1455 |
|
} |
1456 |
< |
public void run() { invoke(); } |
1456 |
> |
public final void run() { invoke(); } |
1457 |
|
private static final long serialVersionUID = 2838392045355241008L; |
1458 |
|
} |
1459 |
|
|
1466 |
|
* @return the task |
1467 |
|
*/ |
1468 |
|
public static ForkJoinTask<?> adapt(Runnable runnable) { |
1469 |
< |
return new AdaptedRunnable<Void>(runnable, null); |
1469 |
> |
return new AdaptedRunnableAction(runnable); |
1470 |
|
} |
1471 |
|
|
1472 |
|
/** |