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

Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.36 by dl, Tue Aug 4 13:16:54 2009 UTC vs.
Revision 1.48 by dl, Thu May 27 16:46:48 2010 UTC

#	Line 56 | Line 56 | import java.util.WeakHashMap;
56		* exceptions such as {@code IOExceptions} to be thrown. However,
57		* computations may still encounter unchecked exceptions, that are
58		* rethrown to callers attempting to join them. These exceptions may
59	<	* additionally include RejectedExecutionExceptions stemming from
60	<	* internal resource exhaustion such as failure to allocate internal
61	<	* task queues.
59	>	* additionally include {@link RejectedExecutionException} stemming
60	>	* from internal resource exhaustion, such as failure to allocate
61	>	* internal task queues.
62		*
63		* <p>The primary method for awaiting completion and extracting
64		* results of a task is {@link #join}, but there are several variants:
#	Line 80 | Line 80 | import java.util.WeakHashMap;
80		* <p>The execution status of tasks may be queried at several levels
81		* of detail: {@link #isDone} is true if a task completed in any way
82		* (including the case where a task was cancelled without executing);
83	–	* {@link #isCancelled} is true if completion was due to cancellation;
83		* {@link #isCompletedNormally} is true if a task completed without
84	<	* cancellation or encountering an exception; {@link
85	<	* #isCompletedExceptionally} is true if if the task encountered an
86	<	* exception (in which case {@link #getException} returns the
87	<	* exception); {@link #isCancelled} is true if the task was cancelled
88	<	* (in which case {@link #getException} returns a {@link
89	<	* java.util.concurrent.CancellationException}); and {@link
90	<	* #isCompletedAbnormally} is true if a task was either cancelled or
92	<	* encountered an exception.
84	>	* cancellation or encountering an exception; {@link #isCancelled} is
85	>	* true if the task was cancelled (in which case {@link #getException}
86	>	* returns a {@link java.util.concurrent.CancellationException}); and
87	>	* {@link #isCompletedAbnormally} is true if a task was either
88	>	* cancelled or encountered an exception, in which case {@link
89	>	* #getException} will return either the encountered exception or
90	>	* {@link java.util.concurrent.CancellationException}.
91		*
92		* <p>The ForkJoinTask class is not usually directly subclassed.
93		* Instead, you subclass one of the abstract classes that support a
#	Line 125 | Line 123 | import java.util.WeakHashMap;
123		* improve throughput. If too small, then memory and internal task
124		* maintenance overhead may overwhelm processing.
125		*
126	<	* <p>This class provides {@code adapt} methods for {@link
127	<	* java.lang.Runnable} and {@link java.util.concurrent.Callable}, that
128	<	* may be of use when mixing execution of ForkJoinTasks with other
129	<	* kinds of tasks. When all tasks are of this form, consider using a
130	<	* pool in {@link ForkJoinPool#setAsyncMode async mode}.
126	>	* <p>This class provides {@code adapt} methods for {@link Runnable}
127	>	* and {@link Callable}, that may be of use when mixing execution of
128	>	* {@code ForkJoinTasks} with other kinds of tasks. When all tasks
129	>	* are of this form, consider using a pool in
130	>	* {@linkplain ForkJoinPool#setAsyncMode async mode}.
131		*
132		* <p>ForkJoinTasks are {@code Serializable}, which enables them to be
133		* used in extensions such as remote execution frameworks. It is
#	Line 141 | Line 139 | import java.util.WeakHashMap;
139		*/
140		public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
141
142	+	/*
143	+	* See the internal documentation of class ForkJoinPool for a
144	+	* general implementation overview.  ForkJoinTasks are mainly
145	+	* responsible for maintaining their "status" field amidst relays
146	+	* to methods in ForkJoinWorkerThread and ForkJoinPool. The
147	+	* methods of this class are more-or-less layered into (1) basic
148	+	* status maintenance (2) execution and awaiting completion (3)
149	+	* user-level methods that additionally report results. This is
150	+	* sometimes hard to see because this file orders exported methods
151	+	* in a way that flows well in javadocs.
152	+	*/
153	+
154		/**
155		* Run control status bits packed into a single int to minimize
156		* footprint and to ensure atomicity (via CAS).  Status is
157		* initially zero, and takes on nonnegative values until
158		* completed, upon which status holds COMPLETED. CANCELLED, or
159		* EXCEPTIONAL, which use the top 3 bits.  Tasks undergoing
160	<	* blocking waits by other threads have SIGNAL_MASK bits set --
161	<	* bit 15 for external (nonFJ) waits, and the rest a count of
162	<	* waiting FJ threads.  (This representation relies on
163	<	* ForkJoinPool max thread limits). Completion of a stolen task
164	<	* with SIGNAL_MASK bits set awakens waiter via notifyAll. Even
165	<	* though suboptimal for some purposes, we use basic builtin
166	<	* wait/notify to take advantage of "monitor inflation" in JVMs
167	<	* that we would otherwise need to emulate to avoid adding further
168	<	* per-task bookkeeping overhead. Note that bits 16-28 are
169	<	* currently unused. Also value 0x80000000 is available as spare
170	<	* completion value.
160	>	* blocking waits by other threads have the SIGNAL bit set.
161	>	*
162	>	* Completion of a stolen task with SIGNAL set awakens any waiters
163	>	* via notifyAll. Even though suboptimal for some purposes, we use
164	>	* basic builtin wait/notify to take advantage of "monitor
165	>	* inflation" in JVMs that we would otherwise need to emulate to
166	>	* avoid adding further per-task bookkeeping overhead.  We want
167	>	* these monitors to be "fat", i.e., not use biasing or thin-lock
168	>	* techniques, so use some odd coding idioms that tend to avoid
169	>	* them.
170	>	*
171	>	* Note that bits 1-28 are currently unused. Also value
172	>	* 0x80000000 is available as spare completion value.
173		*/
174		volatile int status; // accessed directly by pool and workers
175
176	<	static final int COMPLETION_MASK      = 0xe0000000;
177	<	static final int NORMAL               = 0xe0000000; // == mask
178	<	static final int CANCELLED            = 0xc0000000;
179	<	static final int EXCEPTIONAL          = 0xa0000000;
180	<	static final int SIGNAL_MASK          = 0x0000ffff;
169	<	static final int INTERNAL_SIGNAL_MASK = 0x00007fff;
170	<	static final int EXTERNAL_SIGNAL      = 0x00008000; // top bit of low word
176	>	private static final int COMPLETION_MASK      = 0xe0000000;
177	>	private static final int NORMAL               = 0xe0000000; // == mask
178	>	private static final int CANCELLED            = 0xc0000000;
179	>	private static final int EXCEPTIONAL          = 0xa0000000;
180	>	private static final int SIGNAL               = 0x00000001;
181
182		/**
183		* Table of exceptions thrown by tasks, to enable reporting by
#	Line 181 | Line 191 | public abstract class ForkJoinTask<V> im
191		Collections.synchronizedMap
192		(new WeakHashMap<ForkJoinTask<?>, Throwable>());
193
194	<	// within-package utilities
194	>	// Maintaining completion status
195
196		/**
197	<	* Gets current worker thread, or null if not a worker thread.
198	<	*/
189	<	static ForkJoinWorkerThread getWorker() {
190	<	Thread t = Thread.currentThread();
191	<	return ((t instanceof ForkJoinWorkerThread) ?
192	<	(ForkJoinWorkerThread) t : null);
193	<	}
194	<
195	<	final boolean casStatus(int cmp, int val) {
196	<	return UNSAFE.compareAndSwapInt(this, statusOffset, cmp, val);
197	<	}
198	<
199	<	/**
200	<	* Workaround for not being able to rethrow unchecked exceptions.
201	<	*/
202	<	static void rethrowException(Throwable ex) {
203	<	if (ex != null)
204	<	UNSAFE.throwException(ex);
205	<	}
206	<
207	<	// Setting completion status
208	<
209	<	/**
210	<	* Marks completion and wakes up threads waiting to join this task.
197	>	* Marks completion and wakes up threads waiting to join this task,
198	>	* also clearing signal request bits.
199		*
200		* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
201	+	* @return status on exit
202		*/
203	<	final void setCompletion(int completion) {
215	<	ForkJoinPool pool = getPool();
216	<	if (pool != null) {
217	<	int s; // Clear signal bits while setting completion status
218	<	do {} while ((s = status) >= 0 && !casStatus(s, completion));
219	<
220	<	if ((s & SIGNAL_MASK) != 0) {
221	<	if ((s &= INTERNAL_SIGNAL_MASK) != 0)
222	<	pool.updateRunningCount(s);
223	<	synchronized (this) { notifyAll(); }
224	<	}
225	<	}
226	<	else
227	<	externallySetCompletion(completion);
228	<	}
229	<
230	<	/**
231	<	* Version of setCompletion for non-FJ threads.  Leaves signal
232	<	* bits for unblocked threads to adjust, and always notifies.
233	<	*/
234	<	private void externallySetCompletion(int completion) {
203	>	private int setCompletion(int completion) {
204		int s;
205	<	do {} while ((s = status) >= 0 &&
206	<	!casStatus(s, (s & SIGNAL_MASK) | completion));
207	<	synchronized (this) { notifyAll(); }
208	<	}
209	<
241	<	/**
242	<	* Sets status to indicate normal completion.
243	<	*/
244	<	final void setNormalCompletion() {
245	<	// Try typical fast case -- single CAS, no signal, not already done.
246	<	// Manually expand casStatus to improve chances of inlining it
247	<	if (!UNSAFE.compareAndSwapInt(this, statusOffset, 0, NORMAL))
248	<	setCompletion(NORMAL);
249	<	}
250	<
251	<	// internal waiting and notification
252	<
253	<	/**
254	<	* Performs the actual monitor wait for awaitDone.
255	<	*/
256	<	private void doAwaitDone() {
257	<	// Minimize lock bias and in/de-flation effects by maximizing
258	<	// chances of waiting inside sync
259	<	try {
260	<	while (status >= 0)
261	<	synchronized (this) { if (status >= 0) wait(); }
262	<	} catch (InterruptedException ie) {
263	<	onInterruptedWait();
264	<	}
265	<	}
266	<
267	<	/**
268	<	* Performs the actual timed monitor wait for awaitDone.
269	<	*/
270	<	private void doAwaitDone(long startTime, long nanos) {
271	<	synchronized (this) {
272	<	try {
273	<	while (status >= 0) {
274	<	long nt = nanos - (System.nanoTime() - startTime);
275	<	if (nt <= 0)
276	<	break;
277	<	wait(nt / 1000000, (int) (nt % 1000000));
278	<	}
279	<	} catch (InterruptedException ie) {
280	<	onInterruptedWait();
205	>	while ((s = status) >= 0) {
206	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) {
207	>	if ((s & SIGNAL) != 0)
208	>	synchronized (this) { notifyAll(); }
209	>	return completion;
210		}
211		}
212	+	return s;
213		}
214
285	–	// Awaiting completion
286	–
215		/**
216	<	* Sets status to indicate there is joiner, then waits for join,
217	<	* surrounded with pool notifications.
290	<	*
291	<	* @return status upon exit
216	>	* Record exception and set exceptional completion
217	>	* @return status on exit
218		*/
219	<	private int awaitDone(ForkJoinWorkerThread w,
220	<	boolean maintainParallelism) {
221	<	ForkJoinPool pool = (w == null) ? null : w.pool;
296	<	int s;
297	<	while ((s = status) >= 0) {
298	<	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
299	<	if (pool == null || !pool.preJoin(this, maintainParallelism))
300	<	doAwaitDone();
301	<	if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
302	<	adjustPoolCountsOnUnblock(pool);
303	<	break;
304	<	}
305	<	}
306	<	return s;
219	>	private int setExceptionalCompletion(Throwable rex) {
220	>	exceptionMap.put(this, rex);
221	>	return setCompletion(EXCEPTIONAL);
222		}
223
224		/**
225	<	* Timed version of awaitDone
311	<	*
312	<	* @return status upon exit
225	>	* Blocks a worker thread until completion. Called only by pool.
226		*/
227	<	private int awaitDone(ForkJoinWorkerThread w, long nanos) {
315	<	ForkJoinPool pool = (w == null) ? null : w.pool;
227	>	final void internalAwaitDone() {
228		int s;
229		while ((s = status) >= 0) {
230	<	if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) {
231	<	long startTime = System.nanoTime();
232	<	if (pool == null || !pool.preJoin(this, false))
233	<	doAwaitDone(startTime, nanos);
234	<	if ((s = status) >= 0) {
235	<	adjustPoolCountsOnCancelledWait(pool);
236	<	s = status;
230	>	synchronized(this) {
231	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, s|SIGNAL)){
232	>	do {
233	>	try {
234	>	wait();
235	>	} catch (InterruptedException ie) {
236	>	cancelIfTerminating();
237	>	}
238	>	} while (status >= 0);
239	>	break;
240		}
326	–	if (s < 0 && (s & INTERNAL_SIGNAL_MASK) != 0)
327	–	adjustPoolCountsOnUnblock(pool);
328	–	break;
241		}
242		}
331	–	return s;
243		}
244
245		/**
246	<	* Notifies pool that thread is unblocked. Called by signalled
247	<	* threads when woken by non-FJ threads (which is atypical).
246	>	* Blocks a non-worker-thread until completion.
247	>	* @return status on exit
248		*/
249	<	private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
249	>	private int externalAwaitDone() {
250		int s;
251	<	do {} while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
252	<	if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
253	<	pool.updateRunningCount(s);
254	<	}
255	<
256	<	/**
257	<	* Notifies pool to adjust counts on cancelled or timed out wait.
258	<	*/
259	<	private void adjustPoolCountsOnCancelledWait(ForkJoinPool pool) {
260	<	if (pool != null) {
261	<	int s;
262	<	while ((s = status) >= 0 && (s & INTERNAL_SIGNAL_MASK) != 0) {
263	<	if (casStatus(s, s - 1)) {
353	<	pool.updateRunningCount(1);
251	>	while ((s = status) >= 0) {
252	>	synchronized(this) {
253	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, s|SIGNAL)){
254	>	boolean interrupted = false;
255	>	do {
256	>	try {
257	>	wait();
258	>	} catch (InterruptedException ie) {
259	>	interrupted = true;
260	>	}
261	>	} while ((s = status) >= 0);
262	>	if (interrupted)
263	>	Thread.currentThread().interrupt();
264		break;
265		}
266		}
267		}
268	+	return s;
269		}
270
271		/**
272	<	* Handles interruptions during waits.
273	<	*/
363	<	private void onInterruptedWait() {
364	<	ForkJoinWorkerThread w = getWorker();
365	<	if (w == null)
366	<	Thread.currentThread().interrupt(); // re-interrupt
367	<	else if (w.isTerminating())
368	<	cancelIgnoringExceptions();
369	<	// else if FJworker, ignore interrupt
370	<	}
371	<
372	<	// Recording and reporting exceptions
373	<
374	<	private void setDoneExceptionally(Throwable rex) {
375	<	exceptionMap.put(this, rex);
376	<	setCompletion(EXCEPTIONAL);
377	<	}
378	<
379	<	/**
380	<	* Throws the exception associated with status s.
381	<	*
382	<	* @throws the exception
383	<	*/
384	<	private void reportException(int s) {
385	<	if ((s &= COMPLETION_MASK) < NORMAL) {
386	<	if (s == CANCELLED)
387	<	throw new CancellationException();
388	<	else
389	<	rethrowException(exceptionMap.get(this));
390	<	}
391	<	}
392	<
393	<	/**
394	<	* Returns result or throws exception using j.u.c.Future conventions.
395	<	* Only call when {@code isDone} known to be true.
396	<	*/
397	<	private V reportFutureResult()
398	<	throws ExecutionException, InterruptedException {
399	<	if (Thread.interrupted())
400	<	throw new InterruptedException();
401	<	int s = status & COMPLETION_MASK;
402	<	if (s < NORMAL) {
403	<	Throwable ex;
404	<	if (s == CANCELLED)
405	<	throw new CancellationException();
406	<	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
407	<	throw new ExecutionException(ex);
408	<	}
409	<	return getRawResult();
410	<	}
411	<
412	<	/**
413	<	* Returns result or throws exception using j.u.c.Future conventions
414	<	* with timeouts.
415	<	*/
416	<	private V reportTimedFutureResult()
417	<	throws InterruptedException, ExecutionException, TimeoutException {
418	<	if (Thread.interrupted())
419	<	throw new InterruptedException();
420	<	Throwable ex;
421	<	int s = status & COMPLETION_MASK;
422	<	if (s == NORMAL)
423	<	return getRawResult();
424	<	if (s == CANCELLED)
425	<	throw new CancellationException();
426	<	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
427	<	throw new ExecutionException(ex);
428	<	throw new TimeoutException();
429	<	}
430	<
431	<	// internal execution methods
432	<
433	<	/**
434	<	* Calls exec, recording completion, and rethrowing exception if
435	<	* encountered. Caller should normally check status before calling.
436	<	*
437	<	* @return true if completed normally
272	>	* Unless done, calls exec and records status if completed, but
273	>	* doesn't wait for completion otherwise.
274		*/
275	<	private boolean tryExec() {
276	<	try { // try block must contain only call to exec
277	<	if (!exec())
278	<	return false;
275	>	final void tryExec() {
276	>	try {
277	>	if (status < 0 || !exec())
278	>	return;
279		} catch (Throwable rex) {
280	<	setDoneExceptionally(rex);
281	<	rethrowException(rex);
446	<	return false; // not reached
280	>	setExceptionalCompletion(rex);
281	>	return;
282		}
283	<	setNormalCompletion();
449	<	return true;
283	>	setCompletion(NORMAL); // must be outside try block
284		}
285
286		/**
287	<	* Main execution method used by worker threads. Invokes
288	<	* base computation unless already complete.
287	>	* If not done and this task is next in worker queue, runs it,
288	>	* else waits for it.
289	>	* @return status on exit
290		*/
291	<	final void quietlyExec() {
292	<	if (status >= 0) {
293	<	try {
294	<	if (!exec())
295	<	return;
296	<	} catch (Throwable rex) {
297	<	setDoneExceptionally(rex);
298	<	return;
291	>	private int waitingJoin() {
292	>	int s = status;
293	>	if (s < 0)
294	>	return s;
295	>	Thread t = Thread.currentThread();
296	>	if (t instanceof ForkJoinWorkerThread) {
297	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) t;
298	>	if (w.unpushTask(this)) {
299	>	boolean completed;
300	>	try {
301	>	completed = exec();
302	>	} catch (Throwable rex) {
303	>	return setExceptionalCompletion(rex);
304	>	}
305	>	if (completed)
306	>	return setCompletion(NORMAL);
307		}
308	<	setNormalCompletion();
308	>	return w.pool.awaitJoin(this);
309		}
310	+	else
311	+	return externalAwaitDone();
312		}
313
314		/**
315	<	* Calls exec(), recording but not rethrowing exception.
316	<	* Caller should normally check status before calling.
317	<	*
473	<	* @return true if completed normally
315	>	* Unless done, calls exec and records status if completed, or
316	>	* waits for completion otherwise.
317	>	* @return status on exit
318		*/
319	<	private boolean tryQuietlyInvoke() {
319	>	private int waitingInvoke() {
320	>	int s = status;
321	>	if (s < 0)
322	>	return s;
323	>	boolean completed;
324		try {
325	<	if (!exec())
478	<	return false;
325	>	completed = exec();
326		} catch (Throwable rex) {
327	<	setDoneExceptionally(rex);
481	<	return false;
327	>	return setExceptionalCompletion(rex);
328		}
329	<	setNormalCompletion();
330	<	return true;
329	>	if (completed)
330	>	return setCompletion(NORMAL);
331	>	return waitingJoin();
332		}
333
334		/**
335	<	* Cancels, ignoring any exceptions it throws.
335	>	* If this task is next in worker queue, runs it, else processes other
336	>	* tasks until complete.
337	>	* @return status on exit
338		*/
339	<	final void cancelIgnoringExceptions() {
340	<	try {
341	<	cancel(false);
342	<	} catch (Throwable ignore) {
339	>	private int busyJoin() {
340	>	int s = status;
341	>	if (s < 0)
342	>	return s;
343	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread();
344	>	if (w.unpushTask(this)) {
345	>	boolean completed;
346	>	try {
347	>	completed = exec();
348	>	} catch (Throwable rex) {
349	>	return setExceptionalCompletion(rex);
350	>	}
351	>	if (completed)
352	>	return setCompletion(NORMAL);
353		}
354	+	return w.execWhileJoining(this);
355		}
356
357		/**
358	<	* Main implementation of helpJoin
358	>	* Returns result or throws exception associated with given status.
359	>	* @param s the status
360		*/
361	<	private int busyJoin(ForkJoinWorkerThread w) {
362	<	int s;
363	<	ForkJoinTask<?> t;
364	<	while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null)
365	<	t.quietlyExec();
505	<	return (s >= 0) ? awaitDone(w, false) : s; // block if no work
361	>	private V reportResult(int s) {
362	>	Throwable ex;
363	>	if (s < NORMAL && (ex = getException()) != null)
364	>	UNSAFE.throwException(ex);
365	>	return getRawResult();
366		}
367
368		// public methods
#	Line 511 | Line 371 | public abstract class ForkJoinTask<V> im
371		* Arranges to asynchronously execute this task.  While it is not
372		* necessarily enforced, it is a usage error to fork a task more
373		* than once unless it has completed and been reinitialized.
374	+	* Subsequent modifications to the state of this task or any data
375	+	* it operates on are not necessarily consistently observable by
376	+	* any thread other than the one executing it unless preceded by a
377	+	* call to {@link #join} or related methods, or a call to {@link
378	+	* #isDone} returning {@code true}.
379		*
380		* <p>This method may be invoked only from within {@code
381		* ForkJoinTask} computations (as may be determined using method
#	Line 527 | Line 392 | public abstract class ForkJoinTask<V> im
392		}
393
394		/**
395	<	* Returns the result of the computation when it is ready.
395	>	* Returns the result of the computation when it {@link #isDone is done}.
396		* This method differs from {@link #get()} in that
397		* abnormal completion results in {@code RuntimeException} or
398		* {@code Error}, not {@code ExecutionException}.
#	Line 535 | Line 400 | public abstract class ForkJoinTask<V> im
400		* @return the computed result
401		*/
402		public final V join() {
403	<	ForkJoinWorkerThread w = getWorker();
539	<	if (w == null || status < 0 || !w.unpushTask(this) || !tryExec())
540	<	reportException(awaitDone(w, true));
541	<	return getRawResult();
403	>	return reportResult(waitingJoin());
404		}
405
406		/**
#	Line 549 | Line 411 | public abstract class ForkJoinTask<V> im
411		* @return the computed result
412		*/
413		public final V invoke() {
414	<	if (status >= 0 && tryExec())
553	<	return getRawResult();
554	<	else
555	<	return join();
414	>	return reportResult(waitingInvoke());
415		}
416
417		/**
418		* Forks the given tasks, returning when {@code isDone} holds for
419		* each task or an (unchecked) exception is encountered, in which
420	<	* case the exception is rethrown.  If more than one task
421	<	* encounters an exception, then this method throws any one of
422	<	* these exceptions.  The individual status of each task may be
420	>	* case the exception is rethrown.  If either task encounters an
421	>	* exception, the other one may be, but is not guaranteed to be,
422	>	* cancelled.  If both tasks throw an exception, then this method
423	>	* throws one of them.  The individual status of each task may be
424		* checked using {@link #getException()} and related methods.
425		*
426		* <p>This method may be invoked only from within {@code
#	Line 609 | Line 469 | public abstract class ForkJoinTask<V> im
469		}
470		else if (i != 0)
471		t.fork();
472	<	else {
473	<	t.quietlyInvoke();
614	<	if (ex == null)
615	<	ex = t.getException();
616	<	}
472	>	else if (t.waitingInvoke() < NORMAL && ex == null)
473	>	ex = t.getException();
474		}
475		for (int i = 1; i <= last; ++i) {
476		ForkJoinTask<?> t = tasks[i];
477		if (t != null) {
478		if (ex != null)
479		t.cancel(false);
480	<	else {
481	<	t.quietlyJoin();
625	<	if (ex == null)
626	<	ex = t.getException();
627	<	}
480	>	else if (t.waitingJoin() < NORMAL && ex == null)
481	>	ex = t.getException();
482		}
483		}
484		if (ex != null)
485	<	rethrowException(ex);
485	>	UNSAFE.throwException(ex);
486		}
487
488		/**
#	Line 671 | Line 525 | public abstract class ForkJoinTask<V> im
525		}
526		else if (i != 0)
527		t.fork();
528	<	else {
529	<	t.quietlyInvoke();
676	<	if (ex == null)
677	<	ex = t.getException();
678	<	}
528	>	else if (t.waitingInvoke() < NORMAL && ex == null)
529	>	ex = t.getException();
530		}
531		for (int i = 1; i <= last; ++i) {
532		ForkJoinTask<?> t = ts.get(i);
533		if (t != null) {
534		if (ex != null)
535		t.cancel(false);
536	<	else {
537	<	t.quietlyJoin();
687	<	if (ex == null)
688	<	ex = t.getException();
689	<	}
536	>	else if (t.waitingJoin() < NORMAL && ex == null)
537	>	ex = t.getException();
538		}
539		}
540		if (ex != null)
541	<	rethrowException(ex);
541	>	UNSAFE.throwException(ex);
542		return tasks;
543		}
544
#	Line 724 | Line 572 | public abstract class ForkJoinTask<V> im
572		}
573
574		/**
575	<	* Returns {@code true} if the computation performed by this task
576	<	* has completed (or has been cancelled).
729	<	*
730	<	* @return {@code true} if this computation has completed
575	>	* Cancels, ignoring any exceptions it throws. Used during worker
576	>	* and pool shutdown.
577		*/
578	<	public final boolean isDone() {
579	<	return status < 0;
578	>	final void cancelIgnoringExceptions() {
579	>	try {
580	>	cancel(false);
581	>	} catch (Throwable ignore) {
582	>	}
583		}
584
585		/**
586	<	* Returns {@code true} if this task was cancelled.
738	<	*
739	<	* @return {@code true} if this task was cancelled
586	>	* Cancels ignoring exceptions if worker is terminating
587		*/
588	+	private void cancelIfTerminating() {
589	+	Thread t = Thread.currentThread();
590	+	if ((t instanceof ForkJoinWorkerThread) &&
591	+	((ForkJoinWorkerThread) t).isTerminating()) {
592	+	try {
593	+	cancel(false);
594	+	} catch (Throwable ignore) {
595	+	}
596	+	}
597	+	}
598	+
599	+	public final boolean isDone() {
600	+	return status < 0;
601	+	}
602	+
603		public final boolean isCancelled() {
604		return (status & COMPLETION_MASK) == CANCELLED;
605		}
#	Line 763 | Line 625 | public abstract class ForkJoinTask<V> im
625		}
626
627		/**
766	–	* Returns {@code true} if this task threw an exception.
767	–	*
768	–	* @return {@code true} if this task threw an exception
769	–	*/
770	–	public final boolean isCompletedExceptionally() {
771	–	return (status & COMPLETION_MASK) == EXCEPTIONAL;
772	–	}
773	–
774	–	/**
628		* Returns the exception thrown by the base computation, or a
629		* {@code CancellationException} if cancelled, or {@code null} if
630		* none or if the method has not yet completed.
#	Line 780 | Line 633 | public abstract class ForkJoinTask<V> im
633		*/
634		public final Throwable getException() {
635		int s = status & COMPLETION_MASK;
636	<	if (s >= NORMAL)
637	<	return null;
638	<	if (s == CANCELLED)
786	<	return new CancellationException();
787	<	return exceptionMap.get(this);
636	>	return ((s >= NORMAL)    ? null :
637	>	(s == CANCELLED) ? new CancellationException() :
638	>	exceptionMap.get(this));
639		}
640
641		/**
#	Line 797 | Line 648 | public abstract class ForkJoinTask<V> im
648		* overridable, but overridden versions must invoke {@code super}
649		* implementation to maintain guarantees.
650		*
651	<	* @param ex the exception to throw. If this exception is
652	<	* not a RuntimeException or Error, the actual exception thrown
653	<	* will be a RuntimeException with cause ex.
651	>	* @param ex the exception to throw. If this exception is not a
652	>	* {@code RuntimeException} or {@code Error}, the actual exception
653	>	* thrown will be a {@code RuntimeException} with cause {@code ex}.
654		*/
655		public void completeExceptionally(Throwable ex) {
656	<	setDoneExceptionally((ex instanceof RuntimeException) ||
657	<	(ex instanceof Error) ? ex :
658	<	new RuntimeException(ex));
656	>	setExceptionalCompletion((ex instanceof RuntimeException) ||
657	>	(ex instanceof Error) ? ex :
658	>	new RuntimeException(ex));
659		}
660
661		/**
#	Line 823 | Line 674 | public abstract class ForkJoinTask<V> im
674		try {
675		setRawResult(value);
676		} catch (Throwable rex) {
677	<	setDoneExceptionally(rex);
677	>	setExceptionalCompletion(rex);
678		return;
679		}
680	<	setNormalCompletion();
680	>	setCompletion(NORMAL);
681		}
682
683		public final V get() throws InterruptedException, ExecutionException {
684	<	ForkJoinWorkerThread w = getWorker();
685	<	if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
686	<	awaitDone(w, true);
687	<	return reportFutureResult();
684	>	int s = waitingJoin() & COMPLETION_MASK;
685	>	if (Thread.interrupted())
686	>	throw new InterruptedException();
687	>	if (s < NORMAL) {
688	>	Throwable ex;
689	>	if (s == CANCELLED)
690	>	throw new CancellationException();
691	>	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
692	>	throw new ExecutionException(ex);
693	>	}
694	>	return getRawResult();
695		}
696
697		public final V get(long timeout, TimeUnit unit)
698		throws InterruptedException, ExecutionException, TimeoutException {
699	<	long nanos = unit.toNanos(timeout);
700	<	ForkJoinWorkerThread w = getWorker();
701	<	if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
702	<	awaitDone(w, nanos);
703	<	return reportTimedFutureResult();
699	>	Thread t = Thread.currentThread();
700	>	ForkJoinPool pool;
701	>	if (t instanceof ForkJoinWorkerThread) {
702	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) t;
703	>	if (status >= 0 && w.unpushTask(this))
704	>	tryExec();
705	>	pool = w.pool;
706	>	}
707	>	else
708	>	pool = null;
709	>	/*
710	>	* Timed wait loop intermixes cases for fj (pool != null) and
711	>	* non FJ threads. For FJ, decrement pool count but don't try
712	>	* for replacement; increment count on completion. For non-FJ,
713	>	* deal with interrupts. This is messy, but a little less so
714	>	* than is splitting the FJ and nonFJ cases.
715	>	*/
716	>	boolean interrupted = false;
717	>	boolean dec = false; // true if pool count decremented
718	>	for (;;) {
719	>	if (Thread.interrupted() && pool == null) {
720	>	interrupted = true;
721	>	break;
722	>	}
723	>	int s = status;
724	>	if (s < 0)
725	>	break;
726	>	if (UNSAFE.compareAndSwapInt(this, statusOffset,
727	>	s, s | SIGNAL)) {
728	>	long startTime = System.nanoTime();
729	>	long nanos = unit.toNanos(timeout);
730	>	long nt; // wait time
731	>	while (status >= 0 &&
732	>	(nt = nanos - (System.nanoTime() - startTime)) > 0) {
733	>	if (pool != null && !dec)
734	>	dec = pool.tryDecrementRunningCount();
735	>	else {
736	>	long ms = nt / 1000000;
737	>	int ns = (int) (nt % 1000000);
738	>	try {
739	>	synchronized(this) {
740	>	if (status >= 0)
741	>	wait(ms, ns);
742	>	}
743	>	} catch (InterruptedException ie) {
744	>	if (pool != null)
745	>	cancelIfTerminating();
746	>	else {
747	>	interrupted = true;
748	>	break;
749	>	}
750	>	}
751	>	}
752	>	}
753	>	break;
754	>	}
755	>	}
756	>	if (pool != null && dec)
757	>	pool.updateRunningCount(1);
758	>	if (interrupted)
759	>	throw new InterruptedException();
760	>	int es = status & COMPLETION_MASK;
761	>	if (es != NORMAL) {
762	>	Throwable ex;
763	>	if (es == CANCELLED)
764	>	throw new CancellationException();
765	>	if (es == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
766	>	throw new ExecutionException(ex);
767	>	throw new TimeoutException();
768	>	}
769	>	return getRawResult();
770		}
771
772		/**
773	<	* Possibly executes other tasks until this task is ready, then
774	<	* returns the result of the computation.  This method may be more
775	<	* efficient than {@code join}, but is only applicable when
776	<	* there are no potential dependencies between continuation of the
777	<	* current task and that of any other task that might be executed
778	<	* while helping. (This usually holds for pure divide-and-conquer
779	<	* tasks).
773	>	* Possibly executes other tasks until this task {@link #isDone is
774	>	* done}, then returns the result of the computation.  This method
775	>	* may be more efficient than {@code join}, but is only applicable
776	>	* when there are no potential dependencies between continuation
777	>	* of the current task and that of any other task that might be
778	>	* executed while helping. (This usually holds for pure
779	>	* divide-and-conquer tasks).
780		*
781		* <p>This method may be invoked only from within {@code
782		* ForkJoinTask} computations (as may be determined using method
#	Line 863 | Line 787 | public abstract class ForkJoinTask<V> im
787		* @return the computed result
788		*/
789		public final V helpJoin() {
790	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread();
867	<	if (status < 0 || !w.unpushTask(this) || !tryExec())
868	<	reportException(busyJoin(w));
869	<	return getRawResult();
790	>	return reportResult(busyJoin());
791		}
792
793		/**
794	<	* Possibly executes other tasks until this task is ready.  This
795	<	* method may be useful when processing collections of tasks when
796	<	* some have been cancelled or otherwise known to have aborted.
794	>	* Possibly executes other tasks until this task {@link #isDone is
795	>	* done}.  This method may be useful when processing collections
796	>	* of tasks when some have been cancelled or otherwise known to
797	>	* have aborted.
798		*
799		* <p>This method may be invoked only from within {@code
800		* ForkJoinTask} computations (as may be determined using method
#	Line 881 | Line 803 | public abstract class ForkJoinTask<V> im
803		* ClassCastException}.
804		*/
805		public final void quietlyHelpJoin() {
806	<	if (status >= 0) {
885	<	ForkJoinWorkerThread w =
886	<	(ForkJoinWorkerThread) Thread.currentThread();
887	<	if (!w.unpushTask(this) || !tryQuietlyInvoke())
888	<	busyJoin(w);
889	<	}
806	>	busyJoin();
807		}
808
809		/**
#	Line 896 | Line 813 | public abstract class ForkJoinTask<V> im
813		* known to have aborted.
814		*/
815		public final void quietlyJoin() {
816	<	if (status >= 0) {
900	<	ForkJoinWorkerThread w = getWorker();
901	<	if (w == null || !w.unpushTask(this) || !tryQuietlyInvoke())
902	<	awaitDone(w, true);
903	<	}
816	>	waitingJoin();
817		}
818
819		/**
#	Line 911 | Line 824 | public abstract class ForkJoinTask<V> im
824		* known to have aborted.
825		*/
826		public final void quietlyInvoke() {
827	<	if (status >= 0 && !tryQuietlyInvoke())
915	<	quietlyJoin();
827	>	waitingInvoke();
828		}
829
830		/**
#	Line 1234 | Line 1146 | public abstract class ForkJoinTask<V> im
1146		private static final long serialVersionUID = -7721805057305804111L;
1147
1148		/**
1149	<	* Save the state to a stream.
1149	>	* Saves the state to a stream.
1150		*
1151		* @serialData the current run status and the exception thrown
1152		* during execution, or {@code null} if none
#	Line 1247 | Line 1159 | public abstract class ForkJoinTask<V> im
1159		}
1160
1161		/**
1162	<	* Reconstitute the instance from a stream.
1162	>	* Reconstitutes the instance from a stream.
1163		*
1164		* @param s the stream
1165		*/
1166		private void readObject(java.io.ObjectInputStream s)
1167		throws java.io.IOException, ClassNotFoundException {
1168		s.defaultReadObject();
1169	<	status &= ~INTERNAL_SIGNAL_MASK; // clear internal signal counts
1258	<	status |= EXTERNAL_SIGNAL; // conservatively set external signal
1169	>	status |= SIGNAL; // conservatively set external signal
1170		Object ex = s.readObject();
1171		if (ex != null)
1172	<	setDoneExceptionally((Throwable) ex);
1172	>	setExceptionalCompletion((Throwable) ex);
1173		}
1174
1175		// Unsafe mechanics

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