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

Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.73 by jsr166, Sun Nov 28 21:21:03 2010 UTC vs.
Revision 1.87 by dl, Sun Mar 4 15:52:45 2012 UTC

#	Line 1 | Line 1
1		/*
2		* Written by Doug Lea with assistance from members of JCP JSR-166
3		* Expert Group and released to the public domain, as explained at
4	<	* http://creativecommons.org/licenses/publicdomain
4	>	* http://creativecommons.org/publicdomain/zero/1.0/
5		*/
6
7		package jsr166y;
8	–
8		import java.io.Serializable;
9		import java.util.Collection;
11	–	import java.util.Collections;
10		import java.util.List;
11		import java.util.RandomAccess;
12	<	import java.util.Map;
13	<	import java.util.WeakHashMap;
12	>	import java.lang.ref.WeakReference;
13	>	import java.lang.ref.ReferenceQueue;
14		import java.util.concurrent.Callable;
15		import java.util.concurrent.CancellationException;
16		import java.util.concurrent.ExecutionException;
19	–	import java.util.concurrent.Executor;
20	–	import java.util.concurrent.ExecutorService;
17		import java.util.concurrent.Future;
18		import java.util.concurrent.RejectedExecutionException;
19		import java.util.concurrent.RunnableFuture;
20		import java.util.concurrent.TimeUnit;
21		import java.util.concurrent.TimeoutException;
22	+	import java.util.concurrent.locks.ReentrantLock;
23	+	import java.lang.reflect.Constructor;
24
25		/**
26		* Abstract base class for tasks that run within a {@link ForkJoinPool}.
#	Line 44 | Line 42 | import java.util.concurrent.TimeoutExcep
42		* <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}.
43		* The efficiency of {@code ForkJoinTask}s stems from a set of
44		* restrictions (that are only partially statically enforceable)
45	<	* reflecting their intended use as computational tasks calculating
46	<	* pure functions or operating on purely isolated objects.  The
47	<	* primary coordination mechanisms are {@link #fork}, that arranges
45	>	* reflecting their main use as computational tasks calculating pure
46	>	* functions or operating on purely isolated objects.  The primary
47	>	* coordination mechanisms are {@link #fork}, that arranges
48		* asynchronous execution, and {@link #join}, that doesn't proceed
49		* until the task's result has been computed.  Computations should
50	<	* avoid {@code synchronized} methods or blocks, and should minimize
51	<	* other blocking synchronization apart from joining other tasks or
52	<	* using synchronizers such as Phasers that are advertised to
53	<	* cooperate with fork/join scheduling. Tasks should also not perform
54	<	* blocking IO, and should ideally access variables that are
55	<	* completely independent of those accessed by other running
56	<	* tasks. Minor breaches of these restrictions, for example using
57	<	* shared output streams, may be tolerable in practice, but frequent
58	<	* use may result in poor performance, and the potential to
59	<	* indefinitely stall if the number of threads not waiting for IO or
60	<	* other external synchronization becomes exhausted. This usage
61	<	* restriction is in part enforced by not permitting checked
62	<	* exceptions such as {@code IOExceptions} to be thrown. However,
63	<	* computations may still encounter unchecked exceptions, that are
64	<	* rethrown to callers attempting to join them. These exceptions may
65	<	* additionally include {@link RejectedExecutionException} stemming
66	<	* from internal resource exhaustion, such as failure to allocate
67	<	* internal task queues.
50	>	* ideally avoid {@code synchronized} methods or blocks, and should
51	>	* minimize other blocking synchronization apart from joining other
52	>	* tasks or using synchronizers such as Phasers that are advertised to
53	>	* cooperate with fork/join scheduling. Subdividable tasks should also
54	>	* not perform blocking IO, and should ideally access variables that
55	>	* are completely independent of those accessed by other running
56	>	* tasks. These guidelines are loosely enforced by not permitting
57	>	* checked exceptions such as {@code IOExceptions} to be
58	>	* thrown. However, computations may still encounter unchecked
59	>	* exceptions, that are rethrown to callers attempting to join
60	>	* them. These exceptions may additionally include {@link
61	>	* RejectedExecutionException} stemming from internal resource
62	>	* exhaustion, such as failure to allocate internal task
63	>	* queues. Rethrown exceptions behave in the same way as regular
64	>	* exceptions, but, when possible, contain stack traces (as displayed
65	>	* for example using {@code ex.printStackTrace()}) of both the thread
66	>	* that initiated the computation as well as the thread actually
67	>	* encountering the exception; minimally only the latter.
68	>	*
69	>	* <p>It is possible to define and use ForkJoinTasks that may block,
70	>	* but doing do requires three further considerations: (1) Completion
71	>	* of few if any <em>other</em> tasks should be dependent on a task
72	>	* that blocks on external synchronization or IO. Event-style async
73	>	* tasks that are never joined often fall into this category.  (2) To
74	>	* minimize resource impact, tasks should be small; ideally performing
75	>	* only the (possibly) blocking action. (3) Unless the {@link
76	>	* ForkJoinPool.ManagedBlocker} API is used, or the number of possibly
77	>	* blocked tasks is known to be less than the pool's {@link
78	>	* ForkJoinPool#getParallelism} level, the pool cannot guarantee that
79	>	* enough threads will be available to ensure progress or good
80	>	* performance.
81		*
82		* <p>The primary method for awaiting completion and extracting
83		* results of a task is {@link #join}, but there are several variants:
#	Line 82 | Line 93 | import java.util.concurrent.TimeoutExcep
93		* performs the most common form of parallel invocation: forking a set
94		* of tasks and joining them all.
95		*
96	+	* <p>In the most typical usages, a fork-join pair act like a call
97	+	* (fork) and return (join) from a parallel recursive function. As is
98	+	* the case with other forms of recursive calls, returns (joins)
99	+	* should be performed innermost-first. For example, {@code a.fork();
100	+	* b.fork(); b.join(); a.join();} is likely to be substantially more
101	+	* efficient than joining {@code a} before {@code b}.
102	+	*
103		* <p>The execution status of tasks may be queried at several levels
104		* of detail: {@link #isDone} is true if a task completed in any way
105		* (including the case where a task was cancelled without executing);
#	Line 118 | Line 136 | import java.util.concurrent.TimeoutExcep
136		* supports other methods and techniques (for example the use of
137		* {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that
138		* may be of use in constructing custom subclasses for problems that
139	<	* are not statically structured as DAGs.
139	>	* are not statically structured as DAGs. To support such usages a
140	>	* ForkJoinTask may be atomically <em>tagged</em> with a {@code
141	>	* short} value using {@link #setForkJoinTaskTag} or {@link
142	>	* #compareAndSetForkJoinTaskTag} and checked using {@link
143	>	* #getForkJoinTaskTag}. The ForkJoinTask implementation does not
144	>	* use these {@code protected} methods or tags for any purpose, but
145	>	* they may be of use in the construction of specialized subclasses.
146	>	* For example, parallel graph traversals can use the supplied methods
147	>	* to avoid revisiting nodes/tasks that have already been processed.
148	>	* Also, completion based designs can use them to record that subtasks
149	>	* have completed. (Method names for tagging are bulky in part to
150	>	* encourage definition of methods that reflect their usage patterns.)
151		*
152		* <p>Most base support methods are {@code final}, to prevent
153		* overriding of implementations that are intrinsically tied to the
#	Line 158 | Line 187 | public abstract class ForkJoinTask<V> im
187		* See the internal documentation of class ForkJoinPool for a
188		* general implementation overview.  ForkJoinTasks are mainly
189		* responsible for maintaining their "status" field amidst relays
190	<	* to methods in ForkJoinWorkerThread and ForkJoinPool. The
191	<	* methods of this class are more-or-less layered into (1) basic
192	<	* status maintenance (2) execution and awaiting completion (3)
193	<	* user-level methods that additionally report results. This is
194	<	* sometimes hard to see because this file orders exported methods
195	<	* in a way that flows well in javadocs. In particular, most
196	<	* join mechanics are in method quietlyJoin, below.
190	>	* to methods in ForkJoinWorkerThread and ForkJoinPool.
191	>	*
192	>	* The methods of this class are more-or-less layered into
193	>	* (1) basic status maintenance
194	>	* (2) execution and awaiting completion
195	>	* (3) user-level methods that additionally report results.
196	>	* This is sometimes hard to see because this file orders exported
197	>	* methods in a way that flows well in javadocs.
198		*/
199
200		/*
201		* The status field holds run control status bits packed into a
202		* single int to minimize footprint and to ensure atomicity (via
203		* CAS).  Status is initially zero, and takes on nonnegative
204	<	* values until completed, upon which status holds value
205	<	* NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking
206	<	* waits by other threads have the SIGNAL bit set.  Completion of
207	<	* a stolen task with SIGNAL set awakens any waiters via
208	<	* notifyAll. Even though suboptimal for some purposes, we use
209	<	* basic builtin wait/notify to take advantage of "monitor
210	<	* inflation" in JVMs that we would otherwise need to emulate to
211	<	* avoid adding further per-task bookkeeping overhead.  We want
212	<	* these monitors to be "fat", i.e., not use biasing or thin-lock
213	<	* techniques, so use some odd coding idioms that tend to avoid
214	<	* them.
204	>	* values until completed, upon which status (anded with
205	>	* DONE_MASK) holds value NORMAL, CANCELLED, or EXCEPTIONAL. Tasks
206	>	* undergoing blocking waits by other threads have the SIGNAL bit
207	>	* set.  Completion of a stolen task with SIGNAL set awakens any
208	>	* waiters via notifyAll. Even though suboptimal for some
209	>	* purposes, we use basic builtin wait/notify to take advantage of
210	>	* "monitor inflation" in JVMs that we would otherwise need to
211	>	* emulate to avoid adding further per-task bookkeeping overhead.
212	>	* We want these monitors to be "fat", i.e., not use biasing or
213	>	* thin-lock techniques, so use some odd coding idioms that tend
214	>	* to avoid them, mainly by arranging that every synchronized
215	>	* block performs a wait, notifyAll or both.
216	>	*
217	>	* These control bits occupy only (some of) the upper half (16
218	>	* bits) of status field. The lower bits are used for user-defined
219	>	* tags.
220		*/
221
222		/** The run status of this task */
223		volatile int status; // accessed directly by pool and workers
224	<
225	<	private static final int NORMAL      = -1;
226	<	private static final int CANCELLED   = -2;
227	<	private static final int EXCEPTIONAL = -3;
228	<	private static final int SIGNAL      =  1;
224	>	static final int DONE_MASK   = 0xf0000000;  // mask out non-completion bits
225	>	static final int NORMAL      = 0xf0000000;  // must be negative
226	>	static final int CANCELLED   = 0xc0000000;  // must be < NORMAL
227	>	static final int EXCEPTIONAL = 0x80000000;  // must be < CANCELLED
228	>	static final int SIGNAL      = 0x00010000;  // must be >= 1 << 16
229	>	static final int SMASK       = 0x0000ffff;  // short bits for tags
230
231		/**
232	<	* Table of exceptions thrown by tasks, to enable reporting by
233	<	* callers. Because exceptions are rare, we don't directly keep
234	<	* them with task objects, but instead use a weak ref table.  Note
235	<	* that cancellation exceptions don't appear in the table, but are
236	<	* instead recorded as status values.
201	<	* TODO: Use ConcurrentReferenceHashMap
232	>	* Marks completion and wakes up threads waiting to join this
233	>	* task.
234	>	*
235	>	* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
236	>	* @return completion status on exit
237		*/
238	<	static final Map<ForkJoinTask<?>, Throwable> exceptionMap =
239	<	Collections.synchronizedMap
240	<	(new WeakHashMap<ForkJoinTask<?>, Throwable>());
238	>	private int setCompletion(int completion) {
239	>	for (int s;;) {
240	>	if ((s = status) < 0)
241	>	return s;
242	>	if (U.compareAndSwapInt(this, STATUS, s, s | completion)) {
243	>	if ((s >>> 16) != 0)
244	>	synchronized (this) { notifyAll(); }
245	>	return completion;
246	>	}
247	>	}
248	>	}
249
250	<	// Maintaining completion status
250	>	/**
251	>	* Primary execution method for stolen tasks. Unless done, calls
252	>	* exec and records status if completed, but doesn't wait for
253	>	* completion otherwise.
254	>	*
255	>	* @return status on exit from this method
256	>	*/
257	>	final int doExec() {
258	>	int s; boolean completed;
259	>	if ((s = status) >= 0) {
260	>	try {
261	>	completed = exec();
262	>	} catch (Throwable rex) {
263	>	return setExceptionalCompletion(rex);
264	>	}
265	>	if (completed)
266	>	s = setCompletion(NORMAL);
267	>	}
268	>	return s;
269	>	}
270
271		/**
272	<	* Marks completion and wakes up threads waiting to join this task,
273	<	* also clearing signal request bits.
272	>	* Tries to set SIGNAL status. Used by ForkJoinPool. Other
273	>	* variants are directly incorporated into externalAwaitDone etc.
274		*
275	<	* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
275	>	* @return true if successful
276	>	*/
277	>	final boolean trySetSignal() {
278	>	int s;
279	>	return U.compareAndSwapInt(this, STATUS, s = status, s | SIGNAL);
280	>	}
281	>
282	>	/**
283	>	* Blocks a non-worker-thread until completion.
284	>	* @return status upon completion
285		*/
286	<	private void setCompletion(int completion) {
286	>	private int externalAwaitDone() {
287	>	boolean interrupted = false;
288		int s;
289		while ((s = status) >= 0) {
290	<	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) {
291	<	if (s != 0)
292	<	synchronized (this) { notifyAll(); }
293	<	break;
290	>	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
291	>	synchronized (this) {
292	>	if (status >= 0) {
293	>	try {
294	>	wait();
295	>	} catch (InterruptedException ie) {
296	>	interrupted = true;
297	>	}
298	>	}
299	>	else
300	>	notifyAll();
301	>	}
302		}
303		}
304	+	if (interrupted)
305	+	Thread.currentThread().interrupt();
306	+	return s;
307	+	}
308	+
309	+	/**
310	+	* Blocks a non-worker-thread until completion or interruption.
311	+	*/
312	+	private int externalInterruptibleAwaitDone() throws InterruptedException {
313	+	int s;
314	+	if (Thread.interrupted())
315	+	throw new InterruptedException();
316	+	while ((s = status) >= 0) {
317	+	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
318	+	synchronized (this) {
319	+	if (status >= 0)
320	+	wait();
321	+	else
322	+	notifyAll();
323	+	}
324	+	}
325	+	}
326	+	return s;
327	+	}
328	+
329	+	/**
330	+	* Implementation for join, get, quietlyJoin. Directly handles
331	+	* only cases of already-completed, external wait, and
332	+	* unfork+exec.  Others are relayed to ForkJoinPool.awaitJoin.
333	+	*
334	+	* @return status upon completion
335	+	*/
336	+	private int doJoin() {
337	+	int s; Thread t; ForkJoinWorkerThread wt; ForkJoinPool.WorkQueue w;
338	+	if ((s = status) >= 0) {
339	+	if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
340	+	if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue).
341	+	tryUnpush(this) || (s = doExec()) >= 0)
342	+	s = wt.pool.awaitJoin(w, this);
343	+	}
344	+	else
345	+	s = externalAwaitDone();
346	+	}
347	+	return s;
348	+	}
349	+
350	+	/**
351	+	* Implementation for invoke, quietlyInvoke.
352	+	*
353	+	* @return status upon completion
354	+	*/
355	+	private int doInvoke() {
356	+	int s; Thread t; ForkJoinWorkerThread wt;
357	+	if ((s = doExec()) >= 0) {
358	+	if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)
359	+	s = (wt = (ForkJoinWorkerThread)t).pool.awaitJoin(wt.workQueue,
360	+	this);
361	+	else
362	+	s = externalAwaitDone();
363	+	}
364	+	return s;
365	+	}
366	+
367	+	// Exception table support
368	+
369	+	/**
370	+	* Table of exceptions thrown by tasks, to enable reporting by
371	+	* callers. Because exceptions are rare, we don't directly keep
372	+	* them with task objects, but instead use a weak ref table.  Note
373	+	* that cancellation exceptions don't appear in the table, but are
374	+	* instead recorded as status values.
375	+	*
376	+	* Note: These statics are initialized below in static block.
377	+	*/
378	+	private static final ExceptionNode[] exceptionTable;
379	+	private static final ReentrantLock exceptionTableLock;
380	+	private static final ReferenceQueue<Object> exceptionTableRefQueue;
381	+
382	+	/**
383	+	* Fixed capacity for exceptionTable.
384	+	*/
385	+	private static final int EXCEPTION_MAP_CAPACITY = 32;
386	+
387	+	/**
388	+	* Key-value nodes for exception table.  The chained hash table
389	+	* uses identity comparisons, full locking, and weak references
390	+	* for keys. The table has a fixed capacity because it only
391	+	* maintains task exceptions long enough for joiners to access
392	+	* them, so should never become very large for sustained
393	+	* periods. However, since we do not know when the last joiner
394	+	* completes, we must use weak references and expunge them. We do
395	+	* so on each operation (hence full locking). Also, some thread in
396	+	* any ForkJoinPool will call helpExpungeStaleExceptions when its
397	+	* pool becomes isQuiescent.
398	+	*/
399	+	static final class ExceptionNode extends WeakReference<ForkJoinTask<?>> {
400	+	final Throwable ex;
401	+	ExceptionNode next;
402	+	final long thrower;  // use id not ref to avoid weak cycles
403	+	ExceptionNode(ForkJoinTask<?> task, Throwable ex, ExceptionNode next) {
404	+	super(task, exceptionTableRefQueue);
405	+	this.ex = ex;
406	+	this.next = next;
407	+	this.thrower = Thread.currentThread().getId();
408	+	}
409		}
410
411		/**
#	Line 228 | Line 413 | public abstract class ForkJoinTask<V> im
413		*
414		* @return status on exit
415		*/
416	<	private void setExceptionalCompletion(Throwable rex) {
417	<	exceptionMap.put(this, rex);
418	<	setCompletion(EXCEPTIONAL);
416	>	private int setExceptionalCompletion(Throwable ex) {
417	>	int h = System.identityHashCode(this);
418	>	final ReentrantLock lock = exceptionTableLock;
419	>	lock.lock();
420	>	try {
421	>	expungeStaleExceptions();
422	>	ExceptionNode[] t = exceptionTable;
423	>	int i = h & (t.length - 1);
424	>	for (ExceptionNode e = t[i]; ; e = e.next) {
425	>	if (e == null) {
426	>	t[i] = new ExceptionNode(this, ex, t[i]);
427	>	break;
428	>	}
429	>	if (e.get() == this) // already present
430	>	break;
431	>	}
432	>	} finally {
433	>	lock.unlock();
434	>	}
435	>	return setCompletion(EXCEPTIONAL);
436		}
437
438		/**
439	<	* Blocks a worker thread until completed or timed out.  Called
440	<	* only by pool.
439	>	* Cancels, ignoring any exceptions thrown by cancel. Used during
440	>	* worker and pool shutdown. Cancel is spec'ed not to throw any
441	>	* exceptions, but if it does anyway, we have no recourse during
442	>	* shutdown, so guard against this case.
443		*/
444	<	final void internalAwaitDone(long millis, int nanos) {
445	<	int s = status;
446	<	if ((s == 0 &&
447	<	UNSAFE.compareAndSwapInt(this, statusOffset, 0, SIGNAL)) ||
448	<	s > 0)  {
449	<	try {     // the odd construction reduces lock bias effects
450	<	synchronized (this) {
451	<	if (status > 0)
452	<	wait(millis, nanos);
444	>	static final void cancelIgnoringExceptions(ForkJoinTask<?> t) {
445	>	if (t != null && t.status >= 0) {
446	>	try {
447	>	t.cancel(false);
448	>	} catch (Throwable ignore) {
449	>	}
450	>	}
451	>	}
452	>
453	>	/**
454	>	* Removes exception node and clears status
455	>	*/
456	>	private void clearExceptionalCompletion() {
457	>	int h = System.identityHashCode(this);
458	>	final ReentrantLock lock = exceptionTableLock;
459	>	lock.lock();
460	>	try {
461	>	ExceptionNode[] t = exceptionTable;
462	>	int i = h & (t.length - 1);
463	>	ExceptionNode e = t[i];
464	>	ExceptionNode pred = null;
465	>	while (e != null) {
466	>	ExceptionNode next = e.next;
467	>	if (e.get() == this) {
468	>	if (pred == null)
469	>	t[i] = next;
470		else
471	<	notifyAll();
471	>	pred.next = next;
472	>	break;
473		}
474	<	} catch (InterruptedException ie) {
475	<	cancelIfTerminating();
474	>	pred = e;
475	>	e = next;
476		}
477	+	expungeStaleExceptions();
478	+	status = 0;
479	+	} finally {
480	+	lock.unlock();
481		}
482		}
483
484		/**
485	<	* Blocks a non-worker-thread until completion.
486	<	*/
487	<	private void externalAwaitDone() {
488	<	if (status >= 0) {
489	<	boolean interrupted = false;
490	<	synchronized (this) {
491	<	for (;;) {
492	<	int s = status;
493	<	if (s == 0)
494	<	UNSAFE.compareAndSwapInt(this, statusOffset,
495	<	0, SIGNAL);
496	<	else if (s < 0) {
497	<	notifyAll();
498	<	break;
499	<	}
500	<	else {
501	<	try {
502	<	wait();
503	<	} catch (InterruptedException ie) {
504	<	interrupted = true;
505	<	}
506	<	}
485	>	* Returns a rethrowable exception for the given task, if
486	>	* available. To provide accurate stack traces, if the exception
487	>	* was not thrown by the current thread, we try to create a new
488	>	* exception of the same type as the one thrown, but with the
489	>	* recorded exception as its cause. If there is no such
490	>	* constructor, we instead try to use a no-arg constructor,
491	>	* followed by initCause, to the same effect. If none of these
492	>	* apply, or any fail due to other exceptions, we return the
493	>	* recorded exception, which is still correct, although it may
494	>	* contain a misleading stack trace.
495	>	*
496	>	* @return the exception, or null if none
497	>	*/
498	>	private Throwable getThrowableException() {
499	>	if ((status & DONE_MASK) != EXCEPTIONAL)
500	>	return null;
501	>	int h = System.identityHashCode(this);
502	>	ExceptionNode e;
503	>	final ReentrantLock lock = exceptionTableLock;
504	>	lock.lock();
505	>	try {
506	>	expungeStaleExceptions();
507	>	ExceptionNode[] t = exceptionTable;
508	>	e = t[h & (t.length - 1)];
509	>	while (e != null && e.get() != this)
510	>	e = e.next;
511	>	} finally {
512	>	lock.unlock();
513	>	}
514	>	Throwable ex;
515	>	if (e == null || (ex = e.ex) == null)
516	>	return null;
517	>	if (e.thrower != Thread.currentThread().getId()) {
518	>	Class<? extends Throwable> ec = ex.getClass();
519	>	try {
520	>	Constructor<?> noArgCtor = null;
521	>	Constructor<?>[] cs = ec.getConstructors();// public ctors only
522	>	for (int i = 0; i < cs.length; ++i) {
523	>	Constructor<?> c = cs[i];
524	>	Class<?>[] ps = c.getParameterTypes();
525	>	if (ps.length == 0)
526	>	noArgCtor = c;
527	>	else if (ps.length == 1 && ps[0] == Throwable.class)
528	>	return (Throwable)(c.newInstance(ex));
529		}
530	+	if (noArgCtor != null) {
531	+	Throwable wx = (Throwable)(noArgCtor.newInstance());
532	+	wx.initCause(ex);
533	+	return wx;
534	+	}
535	+	} catch (Exception ignore) {
536		}
283	–	if (interrupted)
284	–	Thread.currentThread().interrupt();
537		}
538	+	return ex;
539		}
540
541		/**
542	<	* Blocks a non-worker-thread until completion or interruption or timeout.
542	>	* Poll stale refs and remove them. Call only while holding lock.
543		*/
544	<	private void externalInterruptibleAwaitDone(boolean timed, long nanos)
545	<	throws InterruptedException {
546	<	if (Thread.interrupted())
547	<	throw new InterruptedException();
548	<	if (status >= 0) {
549	<	long startTime = timed ? System.nanoTime() : 0L;
550	<	synchronized (this) {
551	<	for (;;) {
552	<	long nt;
553	<	int s = status;
554	<	if (s == 0)
555	<	UNSAFE.compareAndSwapInt(this, statusOffset,
556	<	0, SIGNAL);
557	<	else if (s < 0) {
558	<	notifyAll();
544	>	private static void expungeStaleExceptions() {
545	>	for (Object x; (x = exceptionTableRefQueue.poll()) != null;) {
546	>	if (x instanceof ExceptionNode) {
547	>	ForkJoinTask<?> key = ((ExceptionNode)x).get();
548	>	ExceptionNode[] t = exceptionTable;
549	>	int i = System.identityHashCode(key) & (t.length - 1);
550	>	ExceptionNode e = t[i];
551	>	ExceptionNode pred = null;
552	>	while (e != null) {
553	>	ExceptionNode next = e.next;
554	>	if (e == x) {
555	>	if (pred == null)
556	>	t[i] = next;
557	>	else
558	>	pred.next = next;
559		break;
560		}
561	<	else if (!timed)
562	<	wait();
310	<	else if ((nt = nanos - (System.nanoTime()-startTime)) > 0L)
311	<	wait(nt / 1000000, (int)(nt % 1000000));
312	<	else
313	<	break;
561	>	pred = e;
562	>	e = next;
563		}
564		}
565		}
566		}
567
568		/**
569	<	* Unless done, calls exec and records status if completed, but
570	<	* doesn't wait for completion otherwise. Primary execution method
322	<	* for ForkJoinWorkerThread.
569	>	* If lock is available, poll stale refs and remove them.
570	>	* Called from ForkJoinPool when pools become quiescent.
571		*/
572	<	final void quietlyExec() {
573	<	try {
574	<	if (status < 0 || !exec())
575	<	return;
576	<	} catch (Throwable rex) {
577	<	setExceptionalCompletion(rex);
578	<	return;
572	>	static final void helpExpungeStaleExceptions() {
573	>	final ReentrantLock lock = exceptionTableLock;
574	>	if (lock.tryLock()) {
575	>	try {
576	>	expungeStaleExceptions();
577	>	} finally {
578	>	lock.unlock();
579	>	}
580		}
581	<	setCompletion(NORMAL); // must be outside try block
581	>	}
582	>
583	>	/**
584	>	* Throws exception, if any, associated with the given status.
585	>	*/
586	>	private void reportException(int s) {
587	>	Throwable ex = ((s == CANCELLED) ?  new CancellationException() :
588	>	(s == EXCEPTIONAL) ? getThrowableException() :
589	>	null);
590	>	if (ex != null)
591	>	U.throwException(ex);
592		}
593
594		// public methods
#	Line 353 | Line 612 | public abstract class ForkJoinTask<V> im
612		* @return {@code this}, to simplify usage
613		*/
614		public final ForkJoinTask<V> fork() {
615	<	((ForkJoinWorkerThread) Thread.currentThread())
357	<	.pushTask(this);
615	>	((ForkJoinWorkerThread)Thread.currentThread()).workQueue.push(this);
616		return this;
617		}
618
#	Line 370 | Line 628 | public abstract class ForkJoinTask<V> im
628		* @return the computed result
629		*/
630		public final V join() {
631	<	quietlyJoin();
632	<	Throwable ex;
633	<	if (status < NORMAL && (ex = getException()) != null)
376	<	UNSAFE.throwException(ex);
631	>	int s;
632	>	if ((s = doJoin() & DONE_MASK) != NORMAL)
633	>	reportException(s);
634		return getRawResult();
635		}
636
#	Line 386 | Line 643 | public abstract class ForkJoinTask<V> im
643		* @return the computed result
644		*/
645		public final V invoke() {
646	<	quietlyInvoke();
647	<	Throwable ex;
648	<	if (status < NORMAL && (ex = getException()) != null)
392	<	UNSAFE.throwException(ex);
646	>	int s;
647	>	if ((s = doInvoke() & DONE_MASK) != NORMAL)
648	>	reportException(s);
649		return getRawResult();
650		}
651
#	Line 417 | Line 673 | public abstract class ForkJoinTask<V> im
673		* @throws NullPointerException if any task is null
674		*/
675		public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) {
676	+	int s1, s2;
677		t2.fork();
678	<	t1.invoke();
679	<	t2.join();
678	>	if ((s1 = t1.doInvoke() & DONE_MASK) != NORMAL)
679	>	t1.reportException(s1);
680	>	if ((s2 = t2.doJoin() & DONE_MASK) != NORMAL)
681	>	t2.reportException(s2);
682		}
683
684		/**
#	Line 454 | Line 713 | public abstract class ForkJoinTask<V> im
713		}
714		else if (i != 0)
715		t.fork();
716	<	else {
717	<	t.quietlyInvoke();
459	<	if (ex == null && t.status < NORMAL)
460	<	ex = t.getException();
461	<	}
716	>	else if (t.doInvoke() < NORMAL && ex == null)
717	>	ex = t.getException();
718		}
719		for (int i = 1; i <= last; ++i) {
720		ForkJoinTask<?> t = tasks[i];
721		if (t != null) {
722		if (ex != null)
723		t.cancel(false);
724	<	else {
725	<	t.quietlyJoin();
470	<	if (ex == null && t.status < NORMAL)
471	<	ex = t.getException();
472	<	}
724	>	else if (t.doJoin() < NORMAL)
725	>	ex = t.getException();
726		}
727		}
728		if (ex != null)
729	<	UNSAFE.throwException(ex);
729	>	U.throwException(ex);
730		}
731
732		/**
#	Line 517 | Line 770 | public abstract class ForkJoinTask<V> im
770		}
771		else if (i != 0)
772		t.fork();
773	<	else {
774	<	t.quietlyInvoke();
522	<	if (ex == null && t.status < NORMAL)
523	<	ex = t.getException();
524	<	}
773	>	else if (t.doInvoke() < NORMAL && ex == null)
774	>	ex = t.getException();
775		}
776		for (int i = 1; i <= last; ++i) {
777		ForkJoinTask<?> t = ts.get(i);
778		if (t != null) {
779		if (ex != null)
780		t.cancel(false);
781	<	else {
782	<	t.quietlyJoin();
533	<	if (ex == null && t.status < NORMAL)
534	<	ex = t.getException();
535	<	}
781	>	else if (t.doJoin() < NORMAL)
782	>	ex = t.getException();
783		}
784		}
785		if (ex != null)
786	<	UNSAFE.throwException(ex);
786	>	U.throwException(ex);
787		return tasks;
788		}
789
#	Line 568 | Line 815 | public abstract class ForkJoinTask<V> im
815		* @return {@code true} if this task is now cancelled
816		*/
817		public boolean cancel(boolean mayInterruptIfRunning) {
818	<	setCompletion(CANCELLED);
572	<	return status == CANCELLED;
573	<	}
574	<
575	<	/**
576	<	* Cancels, ignoring any exceptions thrown by cancel. Used during
577	<	* worker and pool shutdown. Cancel is spec'ed not to throw any
578	<	* exceptions, but if it does anyway, we have no recourse during
579	<	* shutdown, so guard against this case.
580	<	*/
581	<	final void cancelIgnoringExceptions() {
582	<	try {
583	<	cancel(false);
584	<	} catch (Throwable ignore) {
585	<	}
586	<	}
587	<
588	<	/**
589	<	* Cancels if current thread is a terminating worker thread,
590	<	* ignoring any exceptions thrown by cancel.
591	<	*/
592	<	final void cancelIfTerminating() {
593	<	Thread t = Thread.currentThread();
594	<	if ((t instanceof ForkJoinWorkerThread) &&
595	<	((ForkJoinWorkerThread) t).isTerminating()) {
596	<	try {
597	<	cancel(false);
598	<	} catch (Throwable ignore) {
599	<	}
600	<	}
818	>	return (setCompletion(CANCELLED) & DONE_MASK) == CANCELLED;
819		}
820
821		public final boolean isDone() {
#	Line 605 | Line 823 | public abstract class ForkJoinTask<V> im
823		}
824
825		public final boolean isCancelled() {
826	<	return status == CANCELLED;
826	>	return (status & DONE_MASK) == CANCELLED;
827		}
828
829		/**
#	Line 625 | Line 843 | public abstract class ForkJoinTask<V> im
843		* exception and was not cancelled
844		*/
845		public final boolean isCompletedNormally() {
846	<	return status == NORMAL;
846	>	return (status & DONE_MASK) == NORMAL;
847		}
848
849		/**
#	Line 636 | Line 854 | public abstract class ForkJoinTask<V> im
854		* @return the exception, or {@code null} if none
855		*/
856		public final Throwable getException() {
857	<	int s = status;
857	>	int s = status & DONE_MASK;
858		return ((s >= NORMAL)    ? null :
859		(s == CANCELLED) ? new CancellationException() :
860	<	exceptionMap.get(this));
860	>	getThrowableException());
861		}
862
863		/**
#	Line 686 | Line 904 | public abstract class ForkJoinTask<V> im
904		}
905
906		/**
907	+	* Completes this task. The most recent value established by
908	+	* {@link #setRawResult} (or {@code null}) will be returned as the
909	+	* result of subsequent invocations of {@code join} and related
910	+	* operations. This method may be useful when processing sets of
911	+	* tasks when some do not otherwise complete normally. Its use in
912	+	* other situations is discouraged.
913	+	*/
914	+	public final void quietlyComplete() {
915	+	setCompletion(NORMAL);
916	+	}
917	+
918	+	/**
919		* Waits if necessary for the computation to complete, and then
920		* retrieves its result.
921		*
#	Line 697 | Line 927 | public abstract class ForkJoinTask<V> im
927		* member of a ForkJoinPool and was interrupted while waiting
928		*/
929		public final V get() throws InterruptedException, ExecutionException {
930	<	Thread t = Thread.currentThread();
931	<	if (t instanceof ForkJoinWorkerThread)
932	<	quietlyJoin();
933	<	else
934	<	externalInterruptibleAwaitDone(false, 0L);
935	<	int s = status;
936	<	if (s != NORMAL) {
707	<	Throwable ex;
708	<	if (s == CANCELLED)
709	<	throw new CancellationException();
710	<	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
711	<	throw new ExecutionException(ex);
712	<	}
930	>	int s = (Thread.currentThread() instanceof ForkJoinWorkerThread) ?
931	>	doJoin() : externalInterruptibleAwaitDone();
932	>	Throwable ex;
933	>	if ((s &= DONE_MASK) == CANCELLED)
934	>	throw new CancellationException();
935	>	if (s == EXCEPTIONAL && (ex = getThrowableException()) != null)
936	>	throw new ExecutionException(ex);
937		return getRawResult();
938		}
939
#	Line 729 | Line 953 | public abstract class ForkJoinTask<V> im
953		*/
954		public final V get(long timeout, TimeUnit unit)
955		throws InterruptedException, ExecutionException, TimeoutException {
956	<	long nanos = unit.toNanos(timeout);
957	<	Thread t = Thread.currentThread();
958	<	if (t instanceof ForkJoinWorkerThread)
959	<	((ForkJoinWorkerThread)t).joinTask(this, true, nanos);
960	<	else
961	<	externalInterruptibleAwaitDone(true, nanos);
962	<	int s = status;
963	<	if (s != NORMAL) {
956	>	if (Thread.interrupted())
957	>	throw new InterruptedException();
958	>	// Messy in part because we measure in nanosecs, but wait in millisecs
959	>	int s; long ns, ms;
960	>	if ((s = status) >= 0 && (ns = unit.toNanos(timeout)) > 0L) {
961	>	long deadline = System.nanoTime() + ns;
962	>	ForkJoinPool p = null;
963	>	ForkJoinPool.WorkQueue w = null;
964	>	Thread t = Thread.currentThread();
965	>	if (t instanceof ForkJoinWorkerThread) {
966	>	ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
967	>	p = wt.pool;
968	>	w = wt.workQueue;
969	>	s = p.helpJoinOnce(w, this); // no retries on failure
970	>	}
971	>	boolean canBlock = false;
972	>	boolean interrupted = false;
973	>	try {
974	>	while ((s = status) >= 0) {
975	>	if (w != null && w.runState < 0)
976	>	cancelIgnoringExceptions(this);
977	>	else if (!canBlock) {
978	>	if (p == null || p.tryCompensate(this, null))
979	>	canBlock = true;
980	>	}
981	>	else {
982	>	if ((ms = TimeUnit.NANOSECONDS.toMillis(ns)) > 0L &&
983	>	U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
984	>	synchronized (this) {
985	>	if (status >= 0) {
986	>	try {
987	>	wait(ms);
988	>	} catch (InterruptedException ie) {
989	>	if (p == null)
990	>	interrupted = true;
991	>	}
992	>	}
993	>	else
994	>	notifyAll();
995	>	}
996	>	}
997	>	if ((s = status) < 0 || interrupted ||
998	>	(ns = deadline - System.nanoTime()) <= 0L)
999	>	break;
1000	>	}
1001	>	}
1002	>	} finally {
1003	>	if (p != null && canBlock)
1004	>	p.incrementActiveCount();
1005	>	}
1006	>	if (interrupted)
1007	>	throw new InterruptedException();
1008	>	}
1009	>	if ((s &= DONE_MASK) != NORMAL) {
1010		Throwable ex;
1011		if (s == CANCELLED)
1012		throw new CancellationException();
1013	<	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
1013	>	if (s != EXCEPTIONAL)
1014	>	throw new TimeoutException();
1015	>	if ((ex = getThrowableException()) != null)
1016		throw new ExecutionException(ex);
745	–	throw new TimeoutException();
1017		}
1018		return getRawResult();
1019		}
#	Line 754 | Line 1025 | public abstract class ForkJoinTask<V> im
1025		* known to have aborted.
1026		*/
1027		public final void quietlyJoin() {
1028	<	Thread t;
758	<	if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) {
759	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread) t;
760	<	if (status >= 0) {
761	<	if (w.unpushTask(this)) {
762	<	boolean completed;
763	<	try {
764	<	completed = exec();
765	<	} catch (Throwable rex) {
766	<	setExceptionalCompletion(rex);
767	<	return;
768	<	}
769	<	if (completed) {
770	<	setCompletion(NORMAL);
771	<	return;
772	<	}
773	<	}
774	<	w.joinTask(this, false, 0L);
775	<	}
776	<	}
777	<	else
778	<	externalAwaitDone();
1028	>	doJoin();
1029		}
1030
1031		/**
#	Line 784 | Line 1034 | public abstract class ForkJoinTask<V> im
1034		* exception.
1035		*/
1036		public final void quietlyInvoke() {
1037	<	if (status >= 0) {
788	<	boolean completed;
789	<	try {
790	<	completed = exec();
791	<	} catch (Throwable rex) {
792	<	setExceptionalCompletion(rex);
793	<	return;
794	<	}
795	<	if (completed)
796	<	setCompletion(NORMAL);
797	<	else
798	<	quietlyJoin();
799	<	}
1037	>	doInvoke();
1038		}
1039
1040		/**
#	Line 813 | Line 1051 | public abstract class ForkJoinTask<V> im
1051		* ClassCastException}.
1052		*/
1053		public static void helpQuiesce() {
1054	<	((ForkJoinWorkerThread) Thread.currentThread())
1055	<	.helpQuiescePool();
1054	>	ForkJoinWorkerThread wt =
1055	>	(ForkJoinWorkerThread)Thread.currentThread();
1056	>	wt.pool.helpQuiescePool(wt.workQueue);
1057		}
1058
1059		/**
#	Line 834 | Line 1073 | public abstract class ForkJoinTask<V> im
1073		* setRawResult(null)}.
1074		*/
1075		public void reinitialize() {
1076	<	if (status == EXCEPTIONAL)
1077	<	exceptionMap.remove(this);
1078	<	status = 0;
1076	>	if ((status & DONE_MASK) == EXCEPTIONAL)
1077	>	clearExceptionalCompletion();
1078	>	else
1079	>	status = 0;
1080		}
1081
1082		/**
#	Line 881 | Line 1121 | public abstract class ForkJoinTask<V> im
1121		* @return {@code true} if unforked
1122		*/
1123		public boolean tryUnfork() {
1124	<	return ((ForkJoinWorkerThread) Thread.currentThread())
1125	<	.unpushTask(this);
1124	>	return ((ForkJoinWorkerThread)Thread.currentThread())
1125	>	.workQueue.tryUnpush(this);
1126		}
1127
1128		/**
#	Line 901 | Line 1141 | public abstract class ForkJoinTask<V> im
1141		*/
1142		public static int getQueuedTaskCount() {
1143		return ((ForkJoinWorkerThread) Thread.currentThread())
1144	<	.getQueueSize();
1144	>	.workQueue.queueSize();
1145		}
1146
1147		/**
#	Line 923 | Line 1163 | public abstract class ForkJoinTask<V> im
1163		* @return the surplus number of tasks, which may be negative
1164		*/
1165		public static int getSurplusQueuedTaskCount() {
1166	<	return ((ForkJoinWorkerThread) Thread.currentThread())
1167	<	.getEstimatedSurplusTaskCount();
1166	>	/*
1167	>	* The aim of this method is to return a cheap heuristic guide
1168	>	* for task partitioning when programmers, frameworks, tools,
1169	>	* or languages have little or no idea about task granularity.
1170	>	* In essence by offering this method, we ask users only about
1171	>	* tradeoffs in overhead vs expected throughput and its
1172	>	* variance, rather than how finely to partition tasks.
1173	>	*
1174	>	* In a steady state strict (tree-structured) computation,
1175	>	* each thread makes available for stealing enough tasks for
1176	>	* other threads to remain active. Inductively, if all threads
1177	>	* play by the same rules, each thread should make available
1178	>	* only a constant number of tasks.
1179	>	*
1180	>	* The minimum useful constant is just 1. But using a value of
1181	>	* 1 would require immediate replenishment upon each steal to
1182	>	* maintain enough tasks, which is infeasible.  Further,
1183	>	* partitionings/granularities of offered tasks should
1184	>	* minimize steal rates, which in general means that threads
1185	>	* nearer the top of computation tree should generate more
1186	>	* than those nearer the bottom. In perfect steady state, each
1187	>	* thread is at approximately the same level of computation
1188	>	* tree. However, producing extra tasks amortizes the
1189	>	* uncertainty of progress and diffusion assumptions.
1190	>	*
1191	>	* So, users will want to use values larger, but not much
1192	>	* larger than 1 to both smooth over transient shortages and
1193	>	* hedge against uneven progress; as traded off against the
1194	>	* cost of extra task overhead. We leave the user to pick a
1195	>	* threshold value to compare with the results of this call to
1196	>	* guide decisions, but recommend values such as 3.
1197	>	*
1198	>	* When all threads are active, it is on average OK to
1199	>	* estimate surplus strictly locally. In steady-state, if one
1200	>	* thread is maintaining say 2 surplus tasks, then so are
1201	>	* others. So we can just use estimated queue length.
1202	>	* However, this strategy alone leads to serious mis-estimates
1203	>	* in some non-steady-state conditions (ramp-up, ramp-down,
1204	>	* other stalls). We can detect many of these by further
1205	>	* considering the number of "idle" threads, that are known to
1206	>	* have zero queued tasks, so compensate by a factor of
1207	>	* (#idle/#active) threads.
1208	>	*/
1209	>	ForkJoinWorkerThread wt =
1210	>	(ForkJoinWorkerThread)Thread.currentThread();
1211	>	return wt.workQueue.queueSize() - wt.pool.idlePerActive();
1212		}
1213
1214		// Extension methods
#	Line 981 | Line 1265 | public abstract class ForkJoinTask<V> im
1265		* @return the next task, or {@code null} if none are available
1266		*/
1267		protected static ForkJoinTask<?> peekNextLocalTask() {
1268	<	return ((ForkJoinWorkerThread) Thread.currentThread())
985	<	.peekTask();
1268	>	return ((ForkJoinWorkerThread) Thread.currentThread()).workQueue.peek();
1269		}
1270
1271		/**
#	Line 1001 | Line 1284 | public abstract class ForkJoinTask<V> im
1284		*/
1285		protected static ForkJoinTask<?> pollNextLocalTask() {
1286		return ((ForkJoinWorkerThread) Thread.currentThread())
1287	<	.pollLocalTask();
1287	>	.workQueue.nextLocalTask();
1288		}
1289
1290		/**
#	Line 1023 | Line 1306 | public abstract class ForkJoinTask<V> im
1306		* @return a task, or {@code null} if none are available
1307		*/
1308		protected static ForkJoinTask<?> pollTask() {
1309	<	return ((ForkJoinWorkerThread) Thread.currentThread())
1310	<	.pollTask();
1309	>	ForkJoinWorkerThread wt =
1310	>	(ForkJoinWorkerThread)Thread.currentThread();
1311	>	return wt.pool.nextTaskFor(wt.workQueue);
1312	>	}
1313	>
1314	>	// tag operations
1315	>
1316	>	/**
1317	>	* Returns the tag for this task.
1318	>	*
1319	>	* @return the tag for this task
1320	>	* @since 1.8
1321	>	*/
1322	>	public final short getForkJoinTaskTag() {
1323	>	return (short)status;
1324	>	}
1325	>
1326	>	/**
1327	>	* Atomically sets the tag value for this task.
1328	>	*
1329	>	* @param tag the tag value
1330	>	* @return the previous value of the tag
1331	>	* @since 1.8
1332	>	*/
1333	>	public final short setForkJoinTaskTag(short tag) {
1334	>	for (int s;;) {
1335	>	if (U.compareAndSwapInt(this, STATUS, s = status,
1336	>	(s & ~SMASK) | (tag & SMASK)))
1337	>	return (short)s;
1338	>	}
1339	>	}
1340	>
1341	>	/**
1342	>	* Atomically conditionally sets the tag value for this task.
1343	>	* Among other applications, tags can be used as visit markers
1344	>	* in tasks operating on graphs, as in mathods that check: {@code
1345	>	* if (task.compareAndSetForkJoinTaskTag((short)0, (short)1))}
1346	>	* before processing, otherwise exiting because the node has
1347	>	* already been visited.
1348	>	*
1349	>	* @param e the expected tag value
1350	>	* @param tag the new tag value
1351	>	* @return true if successful; i.e., the current value was
1352	>	* equal to e and is now tag.
1353	>	* @since 1.8
1354	>	*/
1355	>	public final boolean compareAndSetForkJoinTaskTag(short e, short tag) {
1356	>	for (int s;;) {
1357	>	if ((short)(s = status) != e)
1358	>	return false;
1359	>	if (U.compareAndSwapInt(this, STATUS, s,
1360	>	(s & ~SMASK) | (tag & SMASK)))
1361	>	return true;
1362	>	}
1363		}
1364
1365		/**
#	Line 1035 | Line 1370 | public abstract class ForkJoinTask<V> im
1370		static final class AdaptedRunnable<T> extends ForkJoinTask<T>
1371		implements RunnableFuture<T> {
1372		final Runnable runnable;
1038	–	final T resultOnCompletion;
1373		T result;
1374		AdaptedRunnable(Runnable runnable, T result) {
1375		if (runnable == null) throw new NullPointerException();
1376		this.runnable = runnable;
1377	<	this.resultOnCompletion = result;
1377	>	this.result = result; // OK to set this even before completion
1378		}
1379	<	public T getRawResult() { return result; }
1380	<	public void setRawResult(T v) { result = v; }
1381	<	public boolean exec() {
1382	<	runnable.run();
1383	<	result = resultOnCompletion;
1384	<	return true;
1379	>	public final T getRawResult() { return result; }
1380	>	public final void setRawResult(T v) { result = v; }
1381	>	public final boolean exec() { runnable.run(); return true; }
1382	>	public final void run() { invoke(); }
1383	>	private static final long serialVersionUID = 5232453952276885070L;
1384	>	}
1385	>
1386	>	/**
1387	>	* Adaptor for Runnables without results
1388	>	*/
1389	>	static final class AdaptedRunnableAction extends ForkJoinTask<Void>
1390	>	implements RunnableFuture<Void> {
1391	>	final Runnable runnable;
1392	>	AdaptedRunnableAction(Runnable runnable) {
1393	>	if (runnable == null) throw new NullPointerException();
1394	>	this.runnable = runnable;
1395		}
1396	<	public void run() { invoke(); }
1396	>	public final Void getRawResult() { return null; }
1397	>	public final void setRawResult(Void v) { }
1398	>	public final boolean exec() { runnable.run(); return true; }
1399	>	public final void run() { invoke(); }
1400		private static final long serialVersionUID = 5232453952276885070L;
1401		}
1402
#	Line 1064 | Line 1411 | public abstract class ForkJoinTask<V> im
1411		if (callable == null) throw new NullPointerException();
1412		this.callable = callable;
1413		}
1414	<	public T getRawResult() { return result; }
1415	<	public void setRawResult(T v) { result = v; }
1416	<	public boolean exec() {
1414	>	public final T getRawResult() { return result; }
1415	>	public final void setRawResult(T v) { result = v; }
1416	>	public final boolean exec() {
1417		try {
1418		result = callable.call();
1419		return true;
#	Line 1078 | Line 1425 | public abstract class ForkJoinTask<V> im
1425		throw new RuntimeException(ex);
1426		}
1427		}
1428	<	public void run() { invoke(); }
1428	>	public final void run() { invoke(); }
1429		private static final long serialVersionUID = 2838392045355241008L;
1430		}
1431
#	Line 1091 | Line 1438 | public abstract class ForkJoinTask<V> im
1438		* @return the task
1439		*/
1440		public static ForkJoinTask<?> adapt(Runnable runnable) {
1441	<	return new AdaptedRunnable<Void>(runnable, null);
1441	>	return new AdaptedRunnableAction(runnable);
1442		}
1443
1444		/**
#	Line 1125 | Line 1472 | public abstract class ForkJoinTask<V> im
1472		private static final long serialVersionUID = -7721805057305804111L;
1473
1474		/**
1475	<	* Saves the state to a stream (that is, serializes it).
1475	>	* Saves this task to a stream (that is, serializes it).
1476		*
1477		* @serialData the current run status and the exception thrown
1478		* during execution, or {@code null} if none
1132	–	* @param s the stream
1479		*/
1480		private void writeObject(java.io.ObjectOutputStream s)
1481		throws java.io.IOException {
#	Line 1138 | Line 1484 | public abstract class ForkJoinTask<V> im
1484		}
1485
1486		/**
1487	<	* Reconstitutes the instance from a stream (that is, deserializes it).
1142	<	*
1143	<	* @param s the stream
1487	>	* Reconstitutes this task from a stream (that is, deserializes it).
1488		*/
1489		private void readObject(java.io.ObjectInputStream s)
1490		throws java.io.IOException, ClassNotFoundException {
1491		s.defaultReadObject();
1492		Object ex = s.readObject();
1493		if (ex != null)
1494	<	setExceptionalCompletion((Throwable) ex);
1494	>	setExceptionalCompletion((Throwable)ex);
1495		}
1496
1497		// Unsafe mechanics
1498	<
1499	<	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1500	<	private static final long statusOffset =
1501	<	objectFieldOffset("status", ForkJoinTask.class);
1502	<
1503	<	private static long objectFieldOffset(String field, Class<?> klazz) {
1498	>	private static final sun.misc.Unsafe U;
1499	>	private static final long STATUS;
1500	>	static {
1501	>	exceptionTableLock = new ReentrantLock();
1502	>	exceptionTableRefQueue = new ReferenceQueue<Object>();
1503	>	exceptionTable = new ExceptionNode[EXCEPTION_MAP_CAPACITY];
1504		try {
1505	<	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
1506	<	} catch (NoSuchFieldException e) {
1507	<	// Convert Exception to corresponding Error
1508	<	NoSuchFieldError error = new NoSuchFieldError(field);
1509	<	error.initCause(e);
1166	<	throw error;
1505	>	U = getUnsafe();
1506	>	STATUS = U.objectFieldOffset
1507	>	(ForkJoinTask.class.getDeclaredField("status"));
1508	>	} catch (Exception e) {
1509	>	throw new Error(e);
1510		}
1511		}
1512

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