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Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.2 by dl, Wed Jan 7 16:07:37 2009 UTC vs.
Revision 1.73 by jsr166, Sun Nov 28 21:21:03 2010 UTC

#	Line 5 | Line 5
5		*/
6
7		package jsr166y;
8	+
9		import java.io.Serializable;
10	<	import java.util.*;
11	<	import java.util.concurrent.*;
12	<	import java.util.concurrent.atomic.*;
13	<	import sun.misc.Unsafe;
14	<	import java.lang.reflect.*;
10	>	import java.util.Collection;
11	>	import java.util.Collections;
12	>	import java.util.List;
13	>	import java.util.RandomAccess;
14	>	import java.util.Map;
15	>	import java.util.WeakHashMap;
16	>	import java.util.concurrent.Callable;
17	>	import java.util.concurrent.CancellationException;
18	>	import java.util.concurrent.ExecutionException;
19	>	import java.util.concurrent.Executor;
20	>	import java.util.concurrent.ExecutorService;
21	>	import java.util.concurrent.Future;
22	>	import java.util.concurrent.RejectedExecutionException;
23	>	import java.util.concurrent.RunnableFuture;
24	>	import java.util.concurrent.TimeUnit;
25	>	import java.util.concurrent.TimeoutException;
26
27		/**
28	<	* Abstract base class for tasks that run within a {@link
29	<	* ForkJoinPool}.  A ForkJoinTask is a thread-like entity that is much
28	>	* Abstract base class for tasks that run within a {@link ForkJoinPool}.
29	>	* A {@code ForkJoinTask} is a thread-like entity that is much
30		* lighter weight than a normal thread.  Huge numbers of tasks and
31		* subtasks may be hosted by a small number of actual threads in a
32		* ForkJoinPool, at the price of some usage limitations.
33	<	*
34	<	* <p> A "main" ForkJoinTask begins execution when submitted to a
35	<	* {@link ForkJoinPool}. Once started, it will usually in turn start
36	<	* other subtasks.  As indicated by the name of this class, many
37	<	* programs using ForkJoinTasks employ only methods <code>fork</code>
38	<	* and <code>join</code>, or derivatives such as
39	<	* <code>invokeAll</code>.  However, this class also provides a number
40	<	* of other methods that can come into play in advanced usages, as
41	<	* well as extension mechanics that allow support of new forms of
42	<	* fork/join processing.
43	<	*
44	<	* <p>A ForkJoinTask is a lightweight form of {@link Future}.  The
45	<	* efficiency of ForkJoinTasks stems from a set of restrictions (that
46	<	* are only partially statically enforceable) reflecting their
47	<	* intended use as computational tasks calculating pure functions or
48	<	* operating on purely isolated objects.  The primary coordination
49	<	* mechanisms are {@link #fork}, that arranges asynchronous execution,
50	<	* and {@link #join}, that doesn't proceed until the task's result has
51	<	* been computed.  Computations should avoid <code>synchronized</code>
52	<	* methods or blocks, and should minimize other blocking
53	<	* synchronization apart from joining other tasks or using
54	<	* synchronizers such as Phasers that are advertised to cooperate with
55	<	* fork/join scheduling. Tasks should also not perform blocking IO,
56	<	* and should ideally access variables that are completely independent
57	<	* of those accessed by other running tasks. Minor breaches of these
58	<	* restrictions, for example using shared output streams, may be
59	<	* tolerable in practice, but frequent use may result in poor
60	<	* performance, and the potential to indefinitely stall if the number
61	<	* of threads not waiting for IO or other external synchronization
62	<	* becomes exhausted. This usage restriction is in part enforced by
63	<	* not permitting checked exceptions such as <code>IOExceptions</code>
64	<	* to be thrown. However, computations may still encounter unchecked
65	<	* exceptions, that are rethrown to callers attempting join
66	<	* them. These exceptions may additionally include
67	<	* RejectedExecutionExceptions stemming from internal resource
68	<	* exhaustion such as failure to allocate internal task queues.
33	>	*
34	>	* <p>A "main" {@code ForkJoinTask} begins execution when submitted
35	>	* to a {@link ForkJoinPool}.  Once started, it will usually in turn
36	>	* start other subtasks.  As indicated by the name of this class,
37	>	* many programs using {@code ForkJoinTask} employ only methods
38	>	* {@link #fork} and {@link #join}, or derivatives such as {@link
39	>	* #invokeAll(ForkJoinTask...) invokeAll}.  However, this class also
40	>	* provides a number of other methods that can come into play in
41	>	* advanced usages, as well as extension mechanics that allow
42	>	* support of new forms of fork/join processing.
43	>	*
44	>	* <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}.
45	>	* The efficiency of {@code ForkJoinTask}s stems from a set of
46	>	* restrictions (that are only partially statically enforceable)
47	>	* reflecting their intended use as computational tasks calculating
48	>	* pure functions or operating on purely isolated objects.  The
49	>	* primary coordination mechanisms are {@link #fork}, that arranges
50	>	* asynchronous execution, and {@link #join}, that doesn't proceed
51	>	* until the task's result has been computed.  Computations should
52	>	* avoid {@code synchronized} methods or blocks, and should minimize
53	>	* other blocking synchronization apart from joining other tasks or
54	>	* using synchronizers such as Phasers that are advertised to
55	>	* cooperate with fork/join scheduling. Tasks should also not perform
56	>	* blocking IO, and should ideally access variables that are
57	>	* completely independent of those accessed by other running
58	>	* tasks. Minor breaches of these restrictions, for example using
59	>	* shared output streams, may be tolerable in practice, but frequent
60	>	* use may result in poor performance, and the potential to
61	>	* indefinitely stall if the number of threads not waiting for IO or
62	>	* other external synchronization becomes exhausted. This usage
63	>	* restriction is in part enforced by not permitting checked
64	>	* exceptions such as {@code IOExceptions} to be thrown. However,
65	>	* computations may still encounter unchecked exceptions, that are
66	>	* rethrown to callers attempting to join them. These exceptions may
67	>	* additionally include {@link RejectedExecutionException} stemming
68	>	* from internal resource exhaustion, such as failure to allocate
69	>	* internal task queues.
70		*
71		* <p>The primary method for awaiting completion and extracting
72		* results of a task is {@link #join}, but there are several variants:
73		* The {@link Future#get} methods support interruptible and/or timed
74	<	* waits for completion and report results using <code>Future</code>
75	<	* conventions. Method {@link #helpJoin} enables callers to actively
76	<	* execute other tasks while awaiting joins, which is sometimes more
77	<	* efficient but only applies when all subtasks are known to be
78	<	* strictly tree-structured. Method {@link #invoke} is semantically
66	<	* equivalent to <code>fork(); join()</code> but always attempts to
67	<	* begin execution in the current thread. The "<em>quiet</em>" forms
68	<	* of these methods do not extract results or report exceptions. These
74	>	* waits for completion and report results using {@code Future}
75	>	* conventions. Method {@link #invoke} is semantically
76	>	* equivalent to {@code fork(); join()} but always attempts to begin
77	>	* execution in the current thread. The "<em>quiet</em>" forms of
78	>	* these methods do not extract results or report exceptions. These
79		* may be useful when a set of tasks are being executed, and you need
80		* to delay processing of results or exceptions until all complete.
81	<	* Method <code>invokeAll</code> (available in multiple versions)
81	>	* Method {@code invokeAll} (available in multiple versions)
82		* performs the most common form of parallel invocation: forking a set
83		* of tasks and joining them all.
84		*
85	<	* <p> The ForkJoinTask class is not usually directly subclassed.
85	>	* <p>The execution status of tasks may be queried at several levels
86	>	* of detail: {@link #isDone} is true if a task completed in any way
87	>	* (including the case where a task was cancelled without executing);
88	>	* {@link #isCompletedNormally} is true if a task completed without
89	>	* cancellation or encountering an exception; {@link #isCancelled} is
90	>	* true if the task was cancelled (in which case {@link #getException}
91	>	* returns a {@link java.util.concurrent.CancellationException}); and
92	>	* {@link #isCompletedAbnormally} is true if a task was either
93	>	* cancelled or encountered an exception, in which case {@link
94	>	* #getException} will return either the encountered exception or
95	>	* {@link java.util.concurrent.CancellationException}.
96	>	*
97	>	* <p>The ForkJoinTask class is not usually directly subclassed.
98		* Instead, you subclass one of the abstract classes that support a
99	<	* particular style of fork/join processing.  Normally, a concrete
99	>	* particular style of fork/join processing, typically {@link
100	>	* RecursiveAction} for computations that do not return results, or
101	>	* {@link RecursiveTask} for those that do.  Normally, a concrete
102		* ForkJoinTask subclass declares fields comprising its parameters,
103	<	* established in a constructor, and then defines a <code>compute</code>
103	>	* established in a constructor, and then defines a {@code compute}
104		* method that somehow uses the control methods supplied by this base
105	<	* class. While these methods have <code>public</code> access (to allow
106	<	* instances of different task subclasses to call each others
105	>	* class. While these methods have {@code public} access (to allow
106	>	* instances of different task subclasses to call each other's
107		* methods), some of them may only be called from within other
108	<	* ForkJoinTasks. Attempts to invoke them in other contexts result in
109	<	* exceptions or errors including ClassCastException.
108	>	* ForkJoinTasks (as may be determined using method {@link
109	>	* #inForkJoinPool}).  Attempts to invoke them in other contexts
110	>	* result in exceptions or errors, possibly including
111	>	* {@code ClassCastException}.
112	>	*
113	>	* <p>Method {@link #join} and its variants are appropriate for use
114	>	* only when completion dependencies are acyclic; that is, the
115	>	* parallel computation can be described as a directed acyclic graph
116	>	* (DAG). Otherwise, executions may encounter a form of deadlock as
117	>	* tasks cyclically wait for each other.  However, this framework
118	>	* supports other methods and techniques (for example the use of
119	>	* {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that
120	>	* may be of use in constructing custom subclasses for problems that
121	>	* are not statically structured as DAGs.
122		*
123	<	* <p>Most base support methods are <code>final</code> because their
124	<	* implementations are intrinsically tied to the underlying
125	<	* lightweight task scheduling framework, and so cannot be overridden.
126	<	* Developers creating new basic styles of fork/join processing should
127	<	* minimally implement <code>protected</code> methods
128	<	* <code>exec</code>, <code>setRawResult</code>, and
129	<	* <code>getRawResult</code>, while also introducing an abstract
130	<	* computational method that can be implemented in its subclasses,
131	<	* possibly relying on other <code>protected</code> methods provided
96	<	* by this class.
123	>	* <p>Most base support methods are {@code final}, to prevent
124	>	* overriding of implementations that are intrinsically tied to the
125	>	* underlying lightweight task scheduling framework.  Developers
126	>	* creating new basic styles of fork/join processing should minimally
127	>	* implement {@code protected} methods {@link #exec}, {@link
128	>	* #setRawResult}, and {@link #getRawResult}, while also introducing
129	>	* an abstract computational method that can be implemented in its
130	>	* subclasses, possibly relying on other {@code protected} methods
131	>	* provided by this class.
132		*
133		* <p>ForkJoinTasks should perform relatively small amounts of
134	<	* computations, othewise splitting into smaller tasks. As a very
135	<	* rough rule of thumb, a task should perform more than 100 and less
136	<	* than 10000 basic computational steps. If tasks are too big, then
137	<	* parellelism cannot improve throughput. If too small, then memory
138	<	* and internal task maintenance overhead may overwhelm processing.
139	<	*
140	<	* <p>ForkJoinTasks are <code>Serializable</code>, which enables them
141	<	* to be used in extensions such as remote execution frameworks. It is
142	<	* in general sensible to serialize tasks only before or after, but
143	<	* not during execution. Serialization is not relied on during
144	<	* execution itself.
134	>	* computation. Large tasks should be split into smaller subtasks,
135	>	* usually via recursive decomposition. As a very rough rule of thumb,
136	>	* a task should perform more than 100 and less than 10000 basic
137	>	* computational steps, and should avoid indefinite looping. If tasks
138	>	* are too big, then parallelism cannot improve throughput. If too
139	>	* small, then memory and internal task maintenance overhead may
140	>	* overwhelm processing.
141	>	*
142	>	* <p>This class provides {@code adapt} methods for {@link Runnable}
143	>	* and {@link Callable}, that may be of use when mixing execution of
144	>	* {@code ForkJoinTasks} with other kinds of tasks. When all tasks are
145	>	* of this form, consider using a pool constructed in <em>asyncMode</em>.
146	>	*
147	>	* <p>ForkJoinTasks are {@code Serializable}, which enables them to be
148	>	* used in extensions such as remote execution frameworks. It is
149	>	* sensible to serialize tasks only before or after, but not during,
150	>	* execution. Serialization is not relied on during execution itself.
151	>	*
152	>	* @since 1.7
153	>	* @author Doug Lea
154		*/
155		public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
156
157	<	/**
158	<	* Run control status bits packed into a single int to minimize
159	<	* footprint and to ensure atomicity (via CAS).  Status is
160	<	* initially zero, and takes on nonnegative values until
161	<	* completed, upon which status holds COMPLETED. CANCELLED, or
162	<	* EXCEPTIONAL, which use the top 3 bits.  Tasks undergoing
163	<	* blocking waits by other threads have SIGNAL_MASK bits set --
164	<	* bit 15 for external (nonFJ) waits, and the rest a count of
165	<	* waiting FJ threads.  (This representation relies on
166	<	* ForkJoinPool max thread limits). Completion of a stolen task
167	<	* with SIGNAL_MASK bits set awakens waiter via notifyAll. Even
168	<	* though suboptimal for some purposes, we use basic builtin
169	<	* wait/notify to take advantage of "monitor inflation" in JVMs
170	<	* that we would otherwise need to emulate to avoid adding further
171	<	* per-task bookkeeping overhead. Note that bits 16-28 are
172	<	* currently unused. Also value 0x80000000 is available as spare
173	<	* completion value.
174	<	*/
175	<	volatile int status; // accessed directy by pool and workers
176	<
177	<	static final int COMPLETION_MASK      = 0xe0000000;
178	<	static final int NORMAL               = 0xe0000000; // == mask
179	<	static final int CANCELLED            = 0xc0000000;
180	<	static final int EXCEPTIONAL          = 0xa0000000;
181	<	static final int SIGNAL_MASK          = 0x0000ffff;
182	<	static final int INTERNAL_SIGNAL_MASK = 0x00007fff;
183	<	static final int EXTERNAL_SIGNAL      = 0x00008000; // top bit of low word
157	>	/*
158	>	* See the internal documentation of class ForkJoinPool for a
159	>	* general implementation overview.  ForkJoinTasks are mainly
160	>	* responsible for maintaining their "status" field amidst relays
161	>	* to methods in ForkJoinWorkerThread and ForkJoinPool. The
162	>	* methods of this class are more-or-less layered into (1) basic
163	>	* status maintenance (2) execution and awaiting completion (3)
164	>	* user-level methods that additionally report results. This is
165	>	* sometimes hard to see because this file orders exported methods
166	>	* in a way that flows well in javadocs. In particular, most
167	>	* join mechanics are in method quietlyJoin, below.
168	>	*/
169	>
170	>	/*
171	>	* The status field holds run control status bits packed into a
172	>	* single int to minimize footprint and to ensure atomicity (via
173	>	* CAS).  Status is initially zero, and takes on nonnegative
174	>	* values until completed, upon which status holds value
175	>	* NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking
176	>	* waits by other threads have the SIGNAL bit set.  Completion of
177	>	* a stolen task with SIGNAL set awakens any waiters via
178	>	* notifyAll. Even though suboptimal for some purposes, we use
179	>	* basic builtin wait/notify to take advantage of "monitor
180	>	* inflation" in JVMs that we would otherwise need to emulate to
181	>	* avoid adding further per-task bookkeeping overhead.  We want
182	>	* these monitors to be "fat", i.e., not use biasing or thin-lock
183	>	* techniques, so use some odd coding idioms that tend to avoid
184	>	* them.
185	>	*/
186	>
187	>	/** The run status of this task */
188	>	volatile int status; // accessed directly by pool and workers
189	>
190	>	private static final int NORMAL      = -1;
191	>	private static final int CANCELLED   = -2;
192	>	private static final int EXCEPTIONAL = -3;
193	>	private static final int SIGNAL      =  1;
194
195		/**
196		* Table of exceptions thrown by tasks, to enable reporting by
197		* callers. Because exceptions are rare, we don't directly keep
198	<	* them with task objects, but instead us a weak ref table.  Note
198	>	* them with task objects, but instead use a weak ref table.  Note
199		* that cancellation exceptions don't appear in the table, but are
200		* instead recorded as status values.
201	<	* Todo: Use ConcurrentReferenceHashMap
201	>	* TODO: Use ConcurrentReferenceHashMap
202		*/
203		static final Map<ForkJoinTask<?>, Throwable> exceptionMap =
204		Collections.synchronizedMap
205		(new WeakHashMap<ForkJoinTask<?>, Throwable>());
206
207	<	// within-package utilities
154	<
155	<	/**
156	<	* Get current worker thread, or null if not a worker thread
157	<	*/
158	<	static ForkJoinWorkerThread getWorker() {
159	<	Thread t = Thread.currentThread();
160	<	return ((t instanceof ForkJoinWorkerThread)?
161	<	(ForkJoinWorkerThread)t : null);
162	<	}
163	<
164	<	final boolean casStatus(int cmp, int val) {
165	<	return _unsafe.compareAndSwapInt(this, statusOffset, cmp, val);
166	<	}
167	<
168	<	/**
169	<	* Workaround for not being able to rethrow unchecked exceptions.
170	<	*/
171	<	static void rethrowException(Throwable ex) {
172	<	if (ex != null)
173	<	_unsafe.throwException(ex);
174	<	}
175	<
176	<	// Setting completion status
207	>	// Maintaining completion status
208
209		/**
210	<	* Mark completion and wake up threads waiting to join this task.
210	>	* Marks completion and wakes up threads waiting to join this task,
211	>	* also clearing signal request bits.
212	>	*
213		* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
214		*/
215	<	final void setCompletion(int completion) {
183	<	ForkJoinPool pool = getPool();
184	<	if (pool != null) {
185	<	int s; // Clear signal bits while setting completion status
186	<	do;while ((s = status) >= 0 && !casStatus(s, completion));
187	<
188	<	if ((s & SIGNAL_MASK) != 0) {
189	<	if ((s &= INTERNAL_SIGNAL_MASK) != 0)
190	<	pool.updateRunningCount(s);
191	<	synchronized(this) { notifyAll(); }
192	<	}
193	<	}
194	<	else
195	<	externallySetCompletion(completion);
196	<	}
197	<
198	<	/**
199	<	* Version of setCompletion for non-FJ threads.  Leaves signal
200	<	* bits for unblocked threads to adjust, and always notifies.
201	<	*/
202	<	private void externallySetCompletion(int completion) {
203	<	int s;
204	<	do;while ((s = status) >= 0 &&
205	<	!casStatus(s, (s & SIGNAL_MASK) | completion));
206	<	synchronized(this) { notifyAll(); }
207	<	}
208	<
209	<	/**
210	<	* Sets status to indicate normal completion
211	<	*/
212	<	final void setNormalCompletion() {
213	<	// Try typical fast case -- single CAS, no signal, not already done.
214	<	// Manually expand casStatus to improve chances of inlining it
215	<	if (!_unsafe.compareAndSwapInt(this, statusOffset, 0, NORMAL))
216	<	setCompletion(NORMAL);
217	<	}
218	<
219	<	// internal waiting and notification
220	<
221	<	/**
222	<	* Performs the actual monitor wait for awaitDone
223	<	*/
224	<	private void doAwaitDone() {
225	<	// Minimize lock bias and in/de-flation effects by maximizing
226	<	// chances of waiting inside sync
227	<	try {
228	<	while (status >= 0)
229	<	synchronized(this) { if (status >= 0) wait(); }
230	<	} catch (InterruptedException ie) {
231	<	onInterruptedWait();
232	<	}
233	<	}
234	<
235	<	/**
236	<	* Performs the actual monitor wait for awaitDone
237	<	*/
238	<	private void doAwaitDone(long startTime, long nanos) {
239	<	synchronized(this) {
240	<	try {
241	<	while (status >= 0) {
242	<	long nt = nanos - System.nanoTime() - startTime;
243	<	if (nt <= 0)
244	<	break;
245	<	wait(nt / 1000000, (int)(nt % 1000000));
246	<	}
247	<	} catch (InterruptedException ie) {
248	<	onInterruptedWait();
249	<	}
250	<	}
251	<	}
252	<
253	<	// Awaiting completion
254	<
255	<	/**
256	<	* Sets status to indicate there is joiner, then waits for join,
257	<	* surrounded with pool notifications.
258	<	* @return status upon exit
259	<	*/
260	<	final int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) {
261	<	ForkJoinPool pool = w == null? null : w.pool;
215	>	private void setCompletion(int completion) {
216		int s;
217		while ((s = status) >= 0) {
218	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
219	<	if (pool == null || !pool.preJoin(this, maintainParallelism))
220	<	doAwaitDone();
267	<	if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
268	<	adjustPoolCountsOnUnblock(pool);
218	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) {
219	>	if (s != 0)
220	>	synchronized (this) { notifyAll(); }
221		break;
222		}
223		}
272	–	return s;
273	–	}
274	–
275	–	/**
276	–	* Timed version of awaitDone
277	–	* @return status upon exit
278	–	*/
279	–	final int awaitDone(ForkJoinWorkerThread w, long nanos) {
280	–	ForkJoinPool pool = w == null? null : w.pool;
281	–	int s;
282	–	while ((s = status) >= 0) {
283	–	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
284	–	long startTime = System.nanoTime();
285	–	if (pool == null || !pool.preJoin(this, false))
286	–	doAwaitDone(startTime, nanos);
287	–	if ((s = status) >= 0) {
288	–	adjustPoolCountsOnCancelledWait(pool);
289	–	s = status;
290	–	}
291	–	if (s < 0 && (s & INTERNAL_SIGNAL_MASK) != 0)
292	–	adjustPoolCountsOnUnblock(pool);
293	–	break;
294	–	}
295	–	}
296	–	return s;
297	–	}
298	–
299	–	/**
300	–	* Notify pool that thread is unblocked. Called by signalled
301	–	* threads when woken by non-FJ threads (which is atypical).
302	–	*/
303	–	private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
304	–	int s;
305	–	do;while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
306	–	if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
307	–	pool.updateRunningCount(s);
308	–	}
309	–
310	–	/**
311	–	* Notify pool to adjust counts on cancelled or timed out wait
312	–	*/
313	–	private void adjustPoolCountsOnCancelledWait(ForkJoinPool pool) {
314	–	if (pool != null) {
315	–	int s;
316	–	while ((s = status) >= 0 && (s & INTERNAL_SIGNAL_MASK) != 0) {
317	–	if (casStatus(s, s - 1)) {
318	–	pool.updateRunningCount(1);
319	–	break;
320	–	}
321	–	}
322	–	}
224		}
225
226		/**
227	<	* Handle interruptions during waits.
227	>	* Records exception and sets exceptional completion.
228	>	*
229	>	* @return status on exit
230		*/
231	<	private void onInterruptedWait() {
329	<	ForkJoinWorkerThread w = getWorker();
330	<	if (w == null)
331	<	Thread.currentThread().interrupt(); // re-interrupt
332	<	else if (w.isTerminating())
333	<	cancelIgnoreExceptions();
334	<	// else if FJworker, ignore interrupt
335	<	}
336	<
337	<	// Recording and reporting exceptions
338	<
339	<	private void setDoneExceptionally(Throwable rex) {
231	>	private void setExceptionalCompletion(Throwable rex) {
232		exceptionMap.put(this, rex);
233		setCompletion(EXCEPTIONAL);
234		}
235
236		/**
237	<	* Throws the exception associated with status s;
238	<	* @throws the exception
237	>	* Blocks a worker thread until completed or timed out.  Called
238	>	* only by pool.
239		*/
240	<	private void reportException(int s) {
241	<	if ((s &= COMPLETION_MASK) < NORMAL) {
242	<	if (s == CANCELLED)
243	<	throw new CancellationException();
244	<	else
245	<	rethrowException(exceptionMap.get(this));
240	>	final void internalAwaitDone(long millis, int nanos) {
241	>	int s = status;
242	>	if ((s == 0 &&
243	>	UNSAFE.compareAndSwapInt(this, statusOffset, 0, SIGNAL)) ||
244	>	s > 0)  {
245	>	try {     // the odd construction reduces lock bias effects
246	>	synchronized (this) {
247	>	if (status > 0)
248	>	wait(millis, nanos);
249	>	else
250	>	notifyAll();
251	>	}
252	>	} catch (InterruptedException ie) {
253	>	cancelIfTerminating();
254	>	}
255		}
256		}
257
258		/**
259	<	* Returns result or throws exception using j.u.c.Future conventions
359	<	* Only call when isDone known to be true.
259	>	* Blocks a non-worker-thread until completion.
260		*/
261	<	private V reportFutureResult()
262	<	throws ExecutionException, InterruptedException {
263	<	int s = status & COMPLETION_MASK;
264	<	if (s < NORMAL) {
265	<	Throwable ex;
266	<	if (s == CANCELLED)
267	<	throw new CancellationException();
268	<	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
269	<	throw new ExecutionException(ex);
270	<	if (Thread.interrupted())
271	<	throw new InterruptedException();
261	>	private void externalAwaitDone() {
262	>	if (status >= 0) {
263	>	boolean interrupted = false;
264	>	synchronized (this) {
265	>	for (;;) {
266	>	int s = status;
267	>	if (s == 0)
268	>	UNSAFE.compareAndSwapInt(this, statusOffset,
269	>	0, SIGNAL);
270	>	else if (s < 0) {
271	>	notifyAll();
272	>	break;
273	>	}
274	>	else {
275	>	try {
276	>	wait();
277	>	} catch (InterruptedException ie) {
278	>	interrupted = true;
279	>	}
280	>	}
281	>	}
282	>	}
283	>	if (interrupted)
284	>	Thread.currentThread().interrupt();
285		}
373	–	return getRawResult();
286		}
287
288		/**
289	<	* Returns result or throws exception using j.u.c.Future conventions
378	<	* with timeouts
289	>	* Blocks a non-worker-thread until completion or interruption or timeout.
290		*/
291	<	private V reportTimedFutureResult()
292	<	throws InterruptedException, ExecutionException, TimeoutException {
382	<	Throwable ex;
383	<	int s = status & COMPLETION_MASK;
384	<	if (s == NORMAL)
385	<	return getRawResult();
386	<	if (s == CANCELLED)
387	<	throw new CancellationException();
388	<	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
389	<	throw new ExecutionException(ex);
291	>	private void externalInterruptibleAwaitDone(boolean timed, long nanos)
292	>	throws InterruptedException {
293		if (Thread.interrupted())
294		throw new InterruptedException();
392	–	throw new TimeoutException();
393	–	}
394	–
395	–	// internal execution methods
396	–
397	–	/**
398	–	* Calls exec, recording completion, and rethrowing exception if
399	–	* encountered. Caller should normally check status before calling
400	–	* @return true if completed normally
401	–	*/
402	–	private boolean tryExec() {
403	–	try { // try block must contain only call to exec
404	–	if (!exec())
405	–	return false;
406	–	} catch (Throwable rex) {
407	–	setDoneExceptionally(rex);
408	–	rethrowException(rex);
409	–	return false; // not reached
410	–	}
411	–	setNormalCompletion();
412	–	return true;
413	–	}
414	–
415	–	/**
416	–	* Main execution method used by worker threads. Invokes
417	–	* base computation unless already complete
418	–	*/
419	–	final void quietlyExec() {
295		if (status >= 0) {
296	<	try {
297	<	if (!exec())
298	<	return;
299	<	} catch(Throwable rex) {
300	<	setDoneExceptionally(rex);
301	<	return;
296	>	long startTime = timed ? System.nanoTime() : 0L;
297	>	synchronized (this) {
298	>	for (;;) {
299	>	long nt;
300	>	int s = status;
301	>	if (s == 0)
302	>	UNSAFE.compareAndSwapInt(this, statusOffset,
303	>	0, SIGNAL);
304	>	else if (s < 0) {
305	>	notifyAll();
306	>	break;
307	>	}
308	>	else if (!timed)
309	>	wait();
310	>	else if ((nt = nanos - (System.nanoTime()-startTime)) > 0L)
311	>	wait(nt / 1000000, (int)(nt % 1000000));
312	>	else
313	>	break;
314	>	}
315		}
428	–	setNormalCompletion();
316		}
317		}
318
319		/**
320	<	* Calls exec, recording but not rethrowing exception
321	<	* Caller should normally check status before calling
322	<	* @return true if completed normally
320	>	* Unless done, calls exec and records status if completed, but
321	>	* doesn't wait for completion otherwise. Primary execution method
322	>	* for ForkJoinWorkerThread.
323		*/
324	<	private boolean tryQuietlyInvoke() {
324	>	final void quietlyExec() {
325		try {
326	<	if (!exec())
327	<	return false;
326	>	if (status < 0 || !exec())
327	>	return;
328		} catch (Throwable rex) {
329	<	setDoneExceptionally(rex);
330	<	return false;
444	<	}
445	<	setNormalCompletion();
446	<	return true;
447	<	}
448	<
449	<	/**
450	<	* Cancel, ignoring any exceptions it throws
451	<	*/
452	<	final void cancelIgnoreExceptions() {
453	<	try {
454	<	cancel(false);
455	<	} catch(Throwable ignore) {
329	>	setExceptionalCompletion(rex);
330	>	return;
331		}
332	+	setCompletion(NORMAL); // must be outside try block
333		}
334
335		// public methods
#	Line 461 | Line 337 | public abstract class ForkJoinTask<V> im
337		/**
338		* Arranges to asynchronously execute this task.  While it is not
339		* necessarily enforced, it is a usage error to fork a task more
340	<	* than once unless it has completed and been reinitialized.  This
341	<	* method may be invoked only from within ForkJoinTask
342	<	* computations. Attempts to invoke in other contexts result in
343	<	* exceptions or errors including ClassCastException.
340	>	* than once unless it has completed and been reinitialized.
341	>	* Subsequent modifications to the state of this task or any data
342	>	* it operates on are not necessarily consistently observable by
343	>	* any thread other than the one executing it unless preceded by a
344	>	* call to {@link #join} or related methods, or a call to {@link
345	>	* #isDone} returning {@code true}.
346	>	*
347	>	* <p>This method may be invoked only from within {@code
348	>	* ForkJoinPool} computations (as may be determined using method
349	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
350	>	* result in exceptions or errors, possibly including {@code
351	>	* ClassCastException}.
352	>	*
353	>	* @return {@code this}, to simplify usage
354		*/
355	<	public final void fork() {
356	<	((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this);
355	>	public final ForkJoinTask<V> fork() {
356	>	((ForkJoinWorkerThread) Thread.currentThread())
357	>	.pushTask(this);
358	>	return this;
359		}
360
361		/**
362	<	* Returns the result of the computation when it is ready.
363	<	* This method differs from <code>get</code> in that abnormal
364	<	* completion results in RuntimeExceptions or Errors, not
365	<	* ExecutionExceptions.
362	>	* Returns the result of the computation when it {@link #isDone is
363	>	* done}.  This method differs from {@link #get()} in that
364	>	* abnormal completion results in {@code RuntimeException} or
365	>	* {@code Error}, not {@code ExecutionException}, and that
366	>	* interrupts of the calling thread do <em>not</em> cause the
367	>	* method to abruptly return by throwing {@code
368	>	* InterruptedException}.
369		*
370		* @return the computed result
371		*/
372		public final V join() {
373	<	ForkJoinWorkerThread w = getWorker();
374	<	if (w == null || status < 0 || !w.unpushTask(this) || !tryExec())
375	<	reportException(awaitDone(w, true));
373	>	quietlyJoin();
374	>	Throwable ex;
375	>	if (status < NORMAL && (ex = getException()) != null)
376	>	UNSAFE.throwException(ex);
377		return getRawResult();
378		}
379
488	–	public final V get() throws InterruptedException, ExecutionException {
489	–	ForkJoinWorkerThread w = getWorker();
490	–	if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
491	–	awaitDone(w, true);
492	–	return reportFutureResult();
493	–	}
494	–
495	–	public final V get(long timeout, TimeUnit unit)
496	–	throws InterruptedException, ExecutionException, TimeoutException {
497	–	ForkJoinWorkerThread w = getWorker();
498	–	if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
499	–	awaitDone(w, unit.toNanos(timeout));
500	–	return reportTimedFutureResult();
501	–	}
502	–
380		/**
381		* Commences performing this task, awaits its completion if
382	<	* necessary, and return its result.
383	<	* @throws Throwable (a RuntimeException, Error, or unchecked
384	<	* exception) if the underlying computation did so.
382	>	* necessary, and returns its result, or throws an (unchecked)
383	>	* {@code RuntimeException} or {@code Error} if the underlying
384	>	* computation did so.
385	>	*
386		* @return the computed result
387		*/
388		public final V invoke() {
389	<	if (status >= 0 && tryExec())
390	<	return getRawResult();
391	<	else
392	<	return join();
389	>	quietlyInvoke();
390	>	Throwable ex;
391	>	if (status < NORMAL && (ex = getException()) != null)
392	>	UNSAFE.throwException(ex);
393	>	return getRawResult();
394		}
395
396		/**
397	<	* Forks both tasks, returning when <code>isDone</code> holds for
398	<	* both of them or an exception is encountered. This method may be
399	<	* invoked only from within ForkJoinTask computations. Attempts to
400	<	* invoke in other contexts result in exceptions or errors
401	<	* including ClassCastException.
402	<	* @param t1 one task
403	<	* @param t2 the other task
404	<	* @throws NullPointerException if t1 or t2 are null
405	<	* @throws RuntimeException or Error if either task did so.
397	>	* Forks the given tasks, returning when {@code isDone} holds for
398	>	* each task or an (unchecked) exception is encountered, in which
399	>	* case the exception is rethrown. If more than one task
400	>	* encounters an exception, then this method throws any one of
401	>	* these exceptions. If any task encounters an exception, the
402	>	* other may be cancelled. However, the execution status of
403	>	* individual tasks is not guaranteed upon exceptional return. The
404	>	* status of each task may be obtained using {@link
405	>	* #getException()} and related methods to check if they have been
406	>	* cancelled, completed normally or exceptionally, or left
407	>	* unprocessed.
408	>	*
409	>	* <p>This method may be invoked only from within {@code
410	>	* ForkJoinPool} computations (as may be determined using method
411	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
412	>	* result in exceptions or errors, possibly including {@code
413	>	* ClassCastException}.
414	>	*
415	>	* @param t1 the first task
416	>	* @param t2 the second task
417	>	* @throws NullPointerException if any task is null
418		*/
419	<	public static void invokeAll(ForkJoinTask<?>t1, ForkJoinTask<?> t2) {
419	>	public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) {
420		t2.fork();
421		t1.invoke();
422		t2.join();
423		}
424
425		/**
426	<	* Forks the given tasks, returning when <code>isDone</code> holds
427	<	* for all of them. If any task encounters an exception, others
428	<	* may be cancelled.  This method may be invoked only from within
429	<	* ForkJoinTask computations. Attempts to invoke in other contexts
430	<	* result in exceptions or errors including ClassCastException.
431	<	* @param tasks the array of tasks
432	<	* @throws NullPointerException if tasks or any element are null.
433	<	* @throws RuntimeException or Error if any task did so.
426	>	* Forks the given tasks, returning when {@code isDone} holds for
427	>	* each task or an (unchecked) exception is encountered, in which
428	>	* case the exception is rethrown. If more than one task
429	>	* encounters an exception, then this method throws any one of
430	>	* these exceptions. If any task encounters an exception, others
431	>	* may be cancelled. However, the execution status of individual
432	>	* tasks is not guaranteed upon exceptional return. The status of
433	>	* each task may be obtained using {@link #getException()} and
434	>	* related methods to check if they have been cancelled, completed
435	>	* normally or exceptionally, or left unprocessed.
436	>	*
437	>	* <p>This method may be invoked only from within {@code
438	>	* ForkJoinPool} computations (as may be determined using method
439	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
440	>	* result in exceptions or errors, possibly including {@code
441	>	* ClassCastException}.
442	>	*
443	>	* @param tasks the tasks
444	>	* @throws NullPointerException if any task is null
445		*/
446		public static void invokeAll(ForkJoinTask<?>... tasks) {
447		Throwable ex = null;
#	Line 554 | Line 456 | public abstract class ForkJoinTask<V> im
456		t.fork();
457		else {
458		t.quietlyInvoke();
459	<	if (ex == null)
459	>	if (ex == null && t.status < NORMAL)
460		ex = t.getException();
461		}
462		}
#	Line 565 | Line 467 | public abstract class ForkJoinTask<V> im
467		t.cancel(false);
468		else {
469		t.quietlyJoin();
470	<	if (ex == null)
470	>	if (ex == null && t.status < NORMAL)
471		ex = t.getException();
472		}
473		}
474		}
475		if (ex != null)
476	<	rethrowException(ex);
476	>	UNSAFE.throwException(ex);
477		}
478
479		/**
480	<	* Forks all tasks in the collection, returning when
481	<	* <code>isDone</code> holds for all of them. If any task
482	<	* encounters an exception, others may be cancelled.  This method
483	<	* may be invoked only from within ForkJoinTask
484	<	* computations. Attempts to invoke in other contexts resul!t in
485	<	* exceptions or errors including ClassCastException.
480	>	* Forks all tasks in the specified collection, returning when
481	>	* {@code isDone} holds for each task or an (unchecked) exception
482	>	* is encountered, in which case the exception is rethrown. If
483	>	* more than one task encounters an exception, then this method
484	>	* throws any one of these exceptions. If any task encounters an
485	>	* exception, others may be cancelled. However, the execution
486	>	* status of individual tasks is not guaranteed upon exceptional
487	>	* return. The status of each task may be obtained using {@link
488	>	* #getException()} and related methods to check if they have been
489	>	* cancelled, completed normally or exceptionally, or left
490	>	* unprocessed.
491	>	*
492	>	* <p>This method may be invoked only from within {@code
493	>	* ForkJoinPool} computations (as may be determined using method
494	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
495	>	* result in exceptions or errors, possibly including {@code
496	>	* ClassCastException}.
497	>	*
498		* @param tasks the collection of tasks
499	<	* @throws NullPointerException if tasks or any element are null.
500	<	* @throws RuntimeException or Error if any task did so.
499	>	* @return the tasks argument, to simplify usage
500	>	* @throws NullPointerException if tasks or any element are null
501		*/
502	<	public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) {
503	<	if (!(tasks instanceof List)) {
504	<	invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()]));
505	<	return;
502	>	public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) {
503	>	if (!(tasks instanceof RandomAccess) || !(tasks instanceof List<?>)) {
504	>	invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()]));
505	>	return tasks;
506		}
507	+	@SuppressWarnings("unchecked")
508		List<? extends ForkJoinTask<?>> ts =
509	<	(List<? extends ForkJoinTask<?>>)tasks;
509	>	(List<? extends ForkJoinTask<?>>) tasks;
510		Throwable ex = null;
511		int last = ts.size() - 1;
512		for (int i = last; i >= 0; --i) {
#	Line 604 | Line 519 | public abstract class ForkJoinTask<V> im
519		t.fork();
520		else {
521		t.quietlyInvoke();
522	<	if (ex == null)
522	>	if (ex == null && t.status < NORMAL)
523		ex = t.getException();
524		}
525		}
#	Line 615 | Line 530 | public abstract class ForkJoinTask<V> im
530		t.cancel(false);
531		else {
532		t.quietlyJoin();
533	<	if (ex == null)
533	>	if (ex == null && t.status < NORMAL)
534		ex = t.getException();
535		}
536		}
537		}
538		if (ex != null)
539	<	rethrowException(ex);
539	>	UNSAFE.throwException(ex);
540	>	return tasks;
541	>	}
542	>
543	>	/**
544	>	* Attempts to cancel execution of this task. This attempt will
545	>	* fail if the task has already completed or could not be
546	>	* cancelled for some other reason. If successful, and this task
547	>	* has not started when {@code cancel} is called, execution of
548	>	* this task is suppressed. After this method returns
549	>	* successfully, unless there is an intervening call to {@link
550	>	* #reinitialize}, subsequent calls to {@link #isCancelled},
551	>	* {@link #isDone}, and {@code cancel} will return {@code true}
552	>	* and calls to {@link #join} and related methods will result in
553	>	* {@code CancellationException}.
554	>	*
555	>	* <p>This method may be overridden in subclasses, but if so, must
556	>	* still ensure that these properties hold. In particular, the
557	>	* {@code cancel} method itself must not throw exceptions.
558	>	*
559	>	* <p>This method is designed to be invoked by <em>other</em>
560	>	* tasks. To terminate the current task, you can just return or
561	>	* throw an unchecked exception from its computation method, or
562	>	* invoke {@link #completeExceptionally}.
563	>	*
564	>	* @param mayInterruptIfRunning this value has no effect in the
565	>	* default implementation because interrupts are not used to
566	>	* control cancellation.
567	>	*
568	>	* @return {@code true} if this task is now cancelled
569	>	*/
570	>	public boolean cancel(boolean mayInterruptIfRunning) {
571	>	setCompletion(CANCELLED);
572	>	return status == CANCELLED;
573		}
574
575		/**
576	<	* Returns true if the computation performed by this task has
577	<	* completed (or has been cancelled).
578	<	* @return true if this computation has completed
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	<	public final boolean isDone() {
582	<	return status < 0;
581	>	final void cancelIgnoringExceptions() {
582	>	try {
583	>	cancel(false);
584	>	} catch (Throwable ignore) {
585	>	}
586		}
587
588		/**
589	<	* Returns true if this task was cancelled.
590	<	* @return true if this task was cancelled
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	+	}
601	+	}
602	+
603	+	public final boolean isDone() {
604	+	return status < 0;
605	+	}
606	+
607		public final boolean isCancelled() {
608	<	return (status & COMPLETION_MASK) == CANCELLED;
608	>	return status == CANCELLED;
609		}
610
611		/**
612	<	* Returns true if this task threw an exception or was cancelled
613	<	* @return true if this task threw an exception or was cancelled
612	>	* Returns {@code true} if this task threw an exception or was cancelled.
613	>	*
614	>	* @return {@code true} if this task threw an exception or was cancelled
615		*/
616		public final boolean isCompletedAbnormally() {
617	<	return (status & COMPLETION_MASK) < NORMAL;
617	>	return status < NORMAL;
618		}
619
620		/**
621	<	* Returns the exception thrown by the base computation, or a
622	<	* CancellationException if cancelled, or null if none or if the
623	<	* method has not yet completed.
624	<	* @return the exception, or null if none
621	>	* Returns {@code true} if this task completed without throwing an
622	>	* exception and was not cancelled.
623	>	*
624	>	* @return {@code true} if this task completed without throwing an
625	>	* exception and was not cancelled
626		*/
627	<	public final Throwable getException() {
628	<	int s = status & COMPLETION_MASK;
660	<	if (s >= NORMAL)
661	<	return null;
662	<	if (s == CANCELLED)
663	<	return new CancellationException();
664	<	return exceptionMap.get(this);
627	>	public final boolean isCompletedNormally() {
628	>	return status == NORMAL;
629		}
630
631		/**
632	<	* Asserts that the results of this task's computation will not be
633	<	* used. If a cancellation occurs before atempting to execute this
634	<	* task, then execution will be suppressed, <code>isCancelled</code>
671	<	* will report true, and <code>join</code> will result in a
672	<	* <code>CancellationException</code> being thrown. Otherwise, when
673	<	* cancellation races with completion, there are no guarantees
674	<	* about whether <code>isCancelled</code> will report true, whether
675	<	* <code>join</code> will return normally or via an exception, or
676	<	* whether these behaviors will remain consistent upon repeated
677	<	* invocation.
678	<	*
679	<	* <p>This method may be overridden in subclasses, but if so, must
680	<	* still ensure that these minimal properties hold. In particular,
681	<	* the cancel method itself must not throw exceptions.
682	<	*
683	<	* <p> This method is designed to be invoked by <em>other</em>
684	<	* tasks. To terminate the current task, you can just return or
685	<	* throw an unchecked exception from its computation method, or
686	<	* invoke <code>completeExceptionally</code>.
687	<	*
688	<	* @param mayInterruptIfRunning this value is ignored in the
689	<	* default implementation because tasks are not in general
690	<	* cancelled via interruption.
632	>	* Returns the exception thrown by the base computation, or a
633	>	* {@code CancellationException} if cancelled, or {@code null} if
634	>	* none or if the method has not yet completed.
635		*
636	<	* @return true if this task is now cancelled
636	>	* @return the exception, or {@code null} if none
637		*/
638	<	public boolean cancel(boolean mayInterruptIfRunning) {
639	<	setCompletion(CANCELLED);
640	<	return (status & COMPLETION_MASK) == CANCELLED;
638	>	public final Throwable getException() {
639	>	int s = status;
640	>	return ((s >= NORMAL)    ? null :
641	>	(s == CANCELLED) ? new CancellationException() :
642	>	exceptionMap.get(this));
643		}
644
645		/**
646		* Completes this task abnormally, and if not already aborted or
647		* cancelled, causes it to throw the given exception upon
648	<	* <code>join</code> and related operations. This method may be used
648	>	* {@code join} and related operations. This method may be used
649		* to induce exceptions in asynchronous tasks, or to force
650		* completion of tasks that would not otherwise complete.  Its use
651	<	* in other situations is likely to be wrong.  This method is
652	<	* overridable, but overridden versions must invoke <code>super</code>
651	>	* in other situations is discouraged.  This method is
652	>	* overridable, but overridden versions must invoke {@code super}
653		* implementation to maintain guarantees.
654		*
655	<	* @param ex the exception to throw. If this exception is
656	<	* not a RuntimeException or Error, the actual exception thrown
657	<	* will be a RuntimeException with cause ex.
655	>	* @param ex the exception to throw. If this exception is not a
656	>	* {@code RuntimeException} or {@code Error}, the actual exception
657	>	* thrown will be a {@code RuntimeException} with cause {@code ex}.
658		*/
659		public void completeExceptionally(Throwable ex) {
660	<	setDoneExceptionally((ex instanceof RuntimeException) ||
661	<	(ex instanceof Error)? ex :
662	<	new RuntimeException(ex));
660	>	setExceptionalCompletion((ex instanceof RuntimeException) ||
661	>	(ex instanceof Error) ? ex :
662	>	new RuntimeException(ex));
663		}
664
665		/**
666		* Completes this task, and if not already aborted or cancelled,
667	<	* returning a <code>null</code> result upon <code>join</code> and related
668	<	* operations. This method may be used to provide results for
669	<	* asynchronous tasks, or to provide alternative handling for
670	<	* tasks that would not otherwise complete normally. Its use in
671	<	* other situations is likely to be wrong. This method is
672	<	* overridable, but overridden versions must invoke <code>super</code>
673	<	* implementation to maintain guarantees.
667	>	* returning the given value as the result of subsequent
668	>	* invocations of {@code join} and related operations. This method
669	>	* may be used to provide results for asynchronous tasks, or to
670	>	* provide alternative handling for tasks that would not otherwise
671	>	* complete normally. Its use in other situations is
672	>	* discouraged. This method is overridable, but overridden
673	>	* versions must invoke {@code super} implementation to maintain
674	>	* guarantees.
675		*
676	<	* @param value the result value for this task.
676	>	* @param value the result value for this task
677		*/
678		public void complete(V value) {
679		try {
680		setRawResult(value);
681	<	} catch(Throwable rex) {
682	<	setDoneExceptionally(rex);
681	>	} catch (Throwable rex) {
682	>	setExceptionalCompletion(rex);
683		return;
684		}
685	<	setNormalCompletion();
685	>	setCompletion(NORMAL);
686		}
687
688		/**
689	<	* Possibly executes other tasks until this task is ready, then
690	<	* returns the result of the computation.  This method may be more
691	<	* efficient than <code>join</code>, but is only applicable when
745	<	* there are no potemtial dependencies between continuation of the
746	<	* current task and that of any other task that might be executed
747	<	* while helping. (This usually holds for pure divide-and-conquer
748	<	* tasks). This method may be invoked only from within
749	<	* ForkJoinTask computations. Attempts to invoke in other contexts
750	<	* resul!t in exceptions or errors including ClassCastException.
689	>	* Waits if necessary for the computation to complete, and then
690	>	* retrieves its result.
691	>	*
692		* @return the computed result
693	+	* @throws CancellationException if the computation was cancelled
694	+	* @throws ExecutionException if the computation threw an
695	+	* exception
696	+	* @throws InterruptedException if the current thread is not a
697	+	* member of a ForkJoinPool and was interrupted while waiting
698		*/
699	<	public final V helpJoin() {
700	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread());
701	<	if (status < 0 || !w.unpushTask(this) || !tryExec())
702	<	reportException(w.helpJoinTask(this));
699	>	public final V get() throws InterruptedException, ExecutionException {
700	>	Thread t = Thread.currentThread();
701	>	if (t instanceof ForkJoinWorkerThread)
702	>	quietlyJoin();
703	>	else
704	>	externalInterruptibleAwaitDone(false, 0L);
705	>	int s = status;
706	>	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	>	}
713		return getRawResult();
714		}
715
716		/**
717	<	* Possibly executes other tasks until this task is ready.  This
718	<	* method may be invoked only from within ForkJoinTask
719	<	* computations. Attempts to invoke in other contexts resul!t in
720	<	* exceptions or errors including ClassCastException.
717	>	* Waits if necessary for at most the given time for the computation
718	>	* to complete, and then retrieves its result, if available.
719	>	*
720	>	* @param timeout the maximum time to wait
721	>	* @param unit the time unit of the timeout argument
722	>	* @return the computed result
723	>	* @throws CancellationException if the computation was cancelled
724	>	* @throws ExecutionException if the computation threw an
725	>	* exception
726	>	* @throws InterruptedException if the current thread is not a
727	>	* member of a ForkJoinPool and was interrupted while waiting
728	>	* @throws TimeoutException if the wait timed out
729		*/
730	<	public final void quietlyHelpJoin() {
731	<	if (status >= 0) {
732	<	ForkJoinWorkerThread w =
733	<	(ForkJoinWorkerThread)(Thread.currentThread());
734	<	if (!w.unpushTask(this) || !tryQuietlyInvoke())
735	<	w.helpJoinTask(this);
730	>	public final V get(long timeout, TimeUnit unit)
731	>	throws InterruptedException, ExecutionException, TimeoutException {
732	>	long nanos = unit.toNanos(timeout);
733	>	Thread t = Thread.currentThread();
734	>	if (t instanceof ForkJoinWorkerThread)
735	>	((ForkJoinWorkerThread)t).joinTask(this, true, nanos);
736	>	else
737	>	externalInterruptibleAwaitDone(true, nanos);
738	>	int s = status;
739	>	if (s != NORMAL) {
740	>	Throwable ex;
741	>	if (s == CANCELLED)
742	>	throw new CancellationException();
743	>	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
744	>	throw new ExecutionException(ex);
745	>	throw new TimeoutException();
746		}
747	+	return getRawResult();
748		}
749
750		/**
751	<	* Joins this task, without returning its result or throwing an
751	>	* Joins this task, without returning its result or throwing its
752		* exception. This method may be useful when processing
753		* collections of tasks when some have been cancelled or otherwise
754		* known to have aborted.
755		*/
756		public final void quietlyJoin() {
757	<	if (status >= 0) {
758	<	ForkJoinWorkerThread w = getWorker();
759	<	if (w == null || !w.unpushTask(this) || !tryQuietlyInvoke())
760	<	awaitDone(w, true);
757	>	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();
779		}
780
781		/**
782		* Commences performing this task and awaits its completion if
783	<	* necessary, without returning its result or throwing an
784	<	* exception. This method may be useful when processing
793	<	* collections of tasks when some have been cancelled or otherwise
794	<	* known to have aborted.
783	>	* necessary, without returning its result or throwing its
784	>	* exception.
785		*/
786		public final void quietlyInvoke() {
787	<	if (status >= 0 && !tryQuietlyInvoke())
788	<	quietlyJoin();
787	>	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	>	}
800	>	}
801	>
802	>	/**
803	>	* Possibly executes tasks until the pool hosting the current task
804	>	* {@link ForkJoinPool#isQuiescent is quiescent}. This method may
805	>	* be of use in designs in which many tasks are forked, but none
806	>	* are explicitly joined, instead executing them until all are
807	>	* processed.
808	>	*
809	>	* <p>This method may be invoked only from within {@code
810	>	* ForkJoinPool} computations (as may be determined using method
811	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
812	>	* result in exceptions or errors, possibly including {@code
813	>	* ClassCastException}.
814	>	*/
815	>	public static void helpQuiesce() {
816	>	((ForkJoinWorkerThread) Thread.currentThread())
817	>	.helpQuiescePool();
818		}
819
820		/**
821		* Resets the internal bookkeeping state of this task, allowing a
822	<	* subsequent <code>fork</code>. This method allows repeated reuse of
822	>	* subsequent {@code fork}. This method allows repeated reuse of
823		* this task, but only if reuse occurs when this task has either
824		* never been forked, or has been forked, then completed and all
825		* outstanding joins of this task have also completed. Effects
826	<	* under any other usage conditions are not guaranteed, and are
827	<	* almost surely wrong. This method may be useful when executing
826	>	* under any other usage conditions are not guaranteed.
827	>	* This method may be useful when executing
828		* pre-constructed trees of subtasks in loops.
829	+	*
830	+	* <p>Upon completion of this method, {@code isDone()} reports
831	+	* {@code false}, and {@code getException()} reports {@code
832	+	* null}. However, the value returned by {@code getRawResult} is
833	+	* unaffected. To clear this value, you can invoke {@code
834	+	* setRawResult(null)}.
835		*/
836		public void reinitialize() {
837	<	if ((status & COMPLETION_MASK) == EXCEPTIONAL)
837	>	if (status == EXCEPTIONAL)
838		exceptionMap.remove(this);
839		status = 0;
840		}
841
842		/**
843		* Returns the pool hosting the current task execution, or null
844	<	* if this task is executing outside of any pool.
845	<	* @return the pool, or null if none.
844	>	* if this task is executing outside of any ForkJoinPool.
845	>	*
846	>	* @see #inForkJoinPool
847	>	* @return the pool, or {@code null} if none
848		*/
849		public static ForkJoinPool getPool() {
850		Thread t = Thread.currentThread();
851	<	return ((t instanceof ForkJoinWorkerThread)?
852	<	((ForkJoinWorkerThread)t).pool : null);
851	>	return (t instanceof ForkJoinWorkerThread) ?
852	>	((ForkJoinWorkerThread) t).pool : null;
853	>	}
854	>
855	>	/**
856	>	* Returns {@code true} if the current thread is a {@link
857	>	* ForkJoinWorkerThread} executing as a ForkJoinPool computation.
858	>	*
859	>	* @return {@code true} if the current thread is a {@link
860	>	* ForkJoinWorkerThread} executing as a ForkJoinPool computation,
861	>	* or {@code false} otherwise
862	>	*/
863	>	public static boolean inForkJoinPool() {
864	>	return Thread.currentThread() instanceof ForkJoinWorkerThread;
865		}
866
867		/**
#	Line 831 | Line 870 | public abstract class ForkJoinTask<V> im
870		* by the current thread, and has not commenced executing in
871		* another thread.  This method may be useful when arranging
872		* alternative local processing of tasks that could have been, but
873	<	* were not, stolen. This method may be invoked only from within
874	<	* ForkJoinTask computations. Attempts to invoke in other contexts
875	<	* result in exceptions or errors including ClassCastException.
876	<	* @return true if unforked
873	>	* were not, stolen.
874	>	*
875	>	* <p>This method may be invoked only from within {@code
876	>	* ForkJoinPool} computations (as may be determined using method
877	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
878	>	* result in exceptions or errors, possibly including {@code
879	>	* ClassCastException}.
880	>	*
881	>	* @return {@code true} if unforked
882		*/
883		public boolean tryUnfork() {
884	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).unpushTask(this);
885	<	}
842	<
843	<	/**
844	<	* Possibly executes tasks until the pool hosting the current task
845	<	* {@link ForkJoinPool#isQuiescent}. This method may be of use in
846	<	* designs in which many tasks are forked, but none are explicitly
847	<	* joined, instead executing them until all are processed.
848	<	*/
849	<	public static void helpQuiesce() {
850	<	((ForkJoinWorkerThread)(Thread.currentThread())).
851	<	helpQuiescePool();
884	>	return ((ForkJoinWorkerThread) Thread.currentThread())
885	>	.unpushTask(this);
886		}
887
888		/**
#	Line 856 | Line 890 | public abstract class ForkJoinTask<V> im
890		* forked by the current worker thread but not yet executed. This
891		* value may be useful for heuristic decisions about whether to
892		* fork other tasks.
893	+	*
894	+	* <p>This method may be invoked only from within {@code
895	+	* ForkJoinPool} computations (as may be determined using method
896	+	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
897	+	* result in exceptions or errors, possibly including {@code
898	+	* ClassCastException}.
899	+	*
900		* @return the number of tasks
901		*/
902		public static int getQueuedTaskCount() {
903	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
904	<	getQueueSize();
903	>	return ((ForkJoinWorkerThread) Thread.currentThread())
904	>	.getQueueSize();
905		}
906
907		/**
908	<	* Returns a estimate of how many more locally queued tasks are
908	>	* Returns an estimate of how many more locally queued tasks are
909		* held by the current worker thread than there are other worker
910		* threads that might steal them.  This value may be useful for
911		* heuristic decisions about whether to fork other tasks. In many
#	Line 872 | Line 913 | public abstract class ForkJoinTask<V> im
913		* aim to maintain a small constant surplus (for example, 3) of
914		* tasks, and to process computations locally if this threshold is
915		* exceeded.
916	+	*
917	+	* <p>This method may be invoked only from within {@code
918	+	* ForkJoinPool} computations (as may be determined using method
919	+	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
920	+	* result in exceptions or errors, possibly including {@code
921	+	* ClassCastException}.
922	+	*
923		* @return the surplus number of tasks, which may be negative
924		*/
925		public static int getSurplusQueuedTaskCount() {
926	<	return ((ForkJoinWorkerThread)(Thread.currentThread()))
926	>	return ((ForkJoinWorkerThread) Thread.currentThread())
927		.getEstimatedSurplusTaskCount();
928		}
929
930		// Extension methods
931
932		/**
933	<	* Returns the result that would be returned by <code>join</code>,
934	<	* even if this task completed abnormally, or null if this task is
935	<	* not known to have been completed.  This method is designed to
936	<	* aid debugging, as well as to support extensions. Its use in any
937	<	* other context is discouraged.
933	>	* Returns the result that would be returned by {@link #join}, even
934	>	* if this task completed abnormally, or {@code null} if this task
935	>	* is not known to have been completed.  This method is designed
936	>	* to aid debugging, as well as to support extensions. Its use in
937	>	* any other context is discouraged.
938		*
939	<	* @return the result, or null if not completed.
939	>	* @return the result, or {@code null} if not completed
940		*/
941		public abstract V getRawResult();
942
#	Line 907 | Line 955 | public abstract class ForkJoinTask<V> im
955		* called otherwise. The return value controls whether this task
956		* is considered to be done normally. It may return false in
957		* asynchronous actions that require explicit invocations of
958	<	* <code>complete</code> to become joinable. It may throw exceptions
959	<	* to indicate abnormal exit.
960	<	* @return true if completed normally
961	<	* @throws Error or RuntimeException if encountered during computation
958	>	* {@link #complete} to become joinable. It may also throw an
959	>	* (unchecked) exception to indicate abnormal exit.
960	>	*
961	>	* @return {@code true} if completed normally
962		*/
963		protected abstract boolean exec();
964
965		/**
966	<	* Returns, but does not unschedule or execute, the task most
967	<	* recently forked by the current thread but not yet executed, if
968	<	* one is available. There is no guarantee that this task will
969	<	* actually be polled or executed next.
970	<	* This method is designed primarily to support extensions,
971	<	* and is unlikely to be useful otherwise.
966	>	* Returns, but does not unschedule or execute, a task queued by
967	>	* the current thread but not yet executed, if one is immediately
968	>	* available. There is no guarantee that this task will actually
969	>	* be polled or executed next. Conversely, this method may return
970	>	* null even if a task exists but cannot be accessed without
971	>	* contention with other threads.  This method is designed
972	>	* primarily to support extensions, and is unlikely to be useful
973	>	* otherwise.
974		*
975	<	* @return the next task, or null if none are available
975	>	* <p>This method may be invoked only from within {@code
976	>	* ForkJoinPool} computations (as may be determined using method
977	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
978	>	* result in exceptions or errors, possibly including {@code
979	>	* ClassCastException}.
980	>	*
981	>	* @return the next task, or {@code null} if none are available
982		*/
983		protected static ForkJoinTask<?> peekNextLocalTask() {
984	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).peekTask();
984	>	return ((ForkJoinWorkerThread) Thread.currentThread())
985	>	.peekTask();
986		}
987
988		/**
989	<	* Unschedules and returns, without executing, the task most
990	<	* recently forked by the current thread but not yet executed.
991	<	* This method is designed primarily to support extensions,
992	<	* and is unlikely to be useful otherwise.
989	>	* Unschedules and returns, without executing, the next task
990	>	* queued by the current thread but not yet executed.  This method
991	>	* is designed primarily to support extensions, and is unlikely to
992	>	* be useful otherwise.
993	>	*
994	>	* <p>This method may be invoked only from within {@code
995	>	* ForkJoinPool} computations (as may be determined using method
996	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
997	>	* result in exceptions or errors, possibly including {@code
998	>	* ClassCastException}.
999		*
1000	<	* @return the next task, or null if none are available
1000	>	* @return the next task, or {@code null} if none are available
1001		*/
1002		protected static ForkJoinTask<?> pollNextLocalTask() {
1003	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).popTask();
1003	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1004	>	.pollLocalTask();
1005		}
1006
1007		/**
1008	<	* Unschedules and returns, without executing, the task most
1009	<	* recently forked by the current thread but not yet executed, if
1010	<	* one is available, or if not available, a task that was forked
1011	<	* by some other thread, if available. Availability may be
1012	<	* transient, so a <code>null</code> result does not necessarily
1013	<	* imply quiecence of the pool this task is operating in.
1014	<	* This method is designed primarily to support extensions,
1015	<	* and is unlikely to be useful otherwise.
1016	<	*
1017	<	* @return a task, or null if none are available
1008	>	* Unschedules and returns, without executing, the next task
1009	>	* queued by the current thread but not yet executed, if one is
1010	>	* available, or if not available, a task that was forked by some
1011	>	* other thread, if available. Availability may be transient, so a
1012	>	* {@code null} result does not necessarily imply quiescence
1013	>	* of the pool this task is operating in.  This method is designed
1014	>	* primarily to support extensions, and is unlikely to be useful
1015	>	* otherwise.
1016	>	*
1017	>	* <p>This method may be invoked only from within {@code
1018	>	* ForkJoinPool} computations (as may be determined using method
1019	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
1020	>	* result in exceptions or errors, possibly including {@code
1021	>	* ClassCastException}.
1022	>	*
1023	>	* @return a task, or {@code null} if none are available
1024		*/
1025		protected static ForkJoinTask<?> pollTask() {
1026	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).
1027	<	getLocalOrStolenTask();
1026	>	return ((ForkJoinWorkerThread) Thread.currentThread())
1027	>	.pollTask();
1028	>	}
1029	>
1030	>	/**
1031	>	* Adaptor for Runnables. This implements RunnableFuture
1032	>	* to be compliant with AbstractExecutorService constraints
1033	>	* when used in ForkJoinPool.
1034	>	*/
1035	>	static final class AdaptedRunnable<T> extends ForkJoinTask<T>
1036	>	implements RunnableFuture<T> {
1037	>	final Runnable runnable;
1038	>	final T resultOnCompletion;
1039	>	T result;
1040	>	AdaptedRunnable(Runnable runnable, T result) {
1041	>	if (runnable == null) throw new NullPointerException();
1042	>	this.runnable = runnable;
1043	>	this.resultOnCompletion = result;
1044	>	}
1045	>	public T getRawResult() { return result; }
1046	>	public void setRawResult(T v) { result = v; }
1047	>	public boolean exec() {
1048	>	runnable.run();
1049	>	result = resultOnCompletion;
1050	>	return true;
1051	>	}
1052	>	public void run() { invoke(); }
1053	>	private static final long serialVersionUID = 5232453952276885070L;
1054	>	}
1055	>
1056	>	/**
1057	>	* Adaptor for Callables
1058	>	*/
1059	>	static final class AdaptedCallable<T> extends ForkJoinTask<T>
1060	>	implements RunnableFuture<T> {
1061	>	final Callable<? extends T> callable;
1062	>	T result;
1063	>	AdaptedCallable(Callable<? extends T> callable) {
1064	>	if (callable == null) throw new NullPointerException();
1065	>	this.callable = callable;
1066	>	}
1067	>	public T getRawResult() { return result; }
1068	>	public void setRawResult(T v) { result = v; }
1069	>	public boolean exec() {
1070	>	try {
1071	>	result = callable.call();
1072	>	return true;
1073	>	} catch (Error err) {
1074	>	throw err;
1075	>	} catch (RuntimeException rex) {
1076	>	throw rex;
1077	>	} catch (Exception ex) {
1078	>	throw new RuntimeException(ex);
1079	>	}
1080	>	}
1081	>	public void run() { invoke(); }
1082	>	private static final long serialVersionUID = 2838392045355241008L;
1083	>	}
1084	>
1085	>	/**
1086	>	* Returns a new {@code ForkJoinTask} that performs the {@code run}
1087	>	* method of the given {@code Runnable} as its action, and returns
1088	>	* a null result upon {@link #join}.
1089	>	*
1090	>	* @param runnable the runnable action
1091	>	* @return the task
1092	>	*/
1093	>	public static ForkJoinTask<?> adapt(Runnable runnable) {
1094	>	return new AdaptedRunnable<Void>(runnable, null);
1095	>	}
1096	>
1097	>	/**
1098	>	* Returns a new {@code ForkJoinTask} that performs the {@code run}
1099	>	* method of the given {@code Runnable} as its action, and returns
1100	>	* the given result upon {@link #join}.
1101	>	*
1102	>	* @param runnable the runnable action
1103	>	* @param result the result upon completion
1104	>	* @return the task
1105	>	*/
1106	>	public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) {
1107	>	return new AdaptedRunnable<T>(runnable, result);
1108	>	}
1109	>
1110	>	/**
1111	>	* Returns a new {@code ForkJoinTask} that performs the {@code call}
1112	>	* method of the given {@code Callable} as its action, and returns
1113	>	* its result upon {@link #join}, translating any checked exceptions
1114	>	* encountered into {@code RuntimeException}.
1115	>	*
1116	>	* @param callable the callable action
1117	>	* @return the task
1118	>	*/
1119	>	public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) {
1120	>	return new AdaptedCallable<T>(callable);
1121		}
1122
1123		// Serialization support
#	Line 962 | Line 1125 | public abstract class ForkJoinTask<V> im
1125		private static final long serialVersionUID = -7721805057305804111L;
1126
1127		/**
1128	<	* Save the state to a stream.
1128	>	* Saves the state to a stream (that is, serializes it).
1129		*
1130		* @serialData the current run status and the exception thrown
1131	<	* during execution, or null if none.
1131	>	* during execution, or {@code null} if none
1132		* @param s the stream
1133		*/
1134		private void writeObject(java.io.ObjectOutputStream s)
#	Line 975 | Line 1138 | public abstract class ForkJoinTask<V> im
1138		}
1139
1140		/**
1141	<	* Reconstitute the instance from a stream.
1141	>	* Reconstitutes the instance from a stream (that is, deserializes it).
1142	>	*
1143		* @param s the stream
1144		*/
1145		private void readObject(java.io.ObjectInputStream s)
1146		throws java.io.IOException, ClassNotFoundException {
1147		s.defaultReadObject();
984	–	status &= ~INTERNAL_SIGNAL_MASK; // clear internal signal counts
985	–	status |= EXTERNAL_SIGNAL; // conservatively set external signal
1148		Object ex = s.readObject();
1149		if (ex != null)
1150	<	setDoneExceptionally((Throwable)ex);
1150	>	setExceptionalCompletion((Throwable) ex);
1151		}
1152
1153	<	// Temporary Unsafe mechanics for preliminary release
1153	>	// Unsafe mechanics
1154
1155	<	static final Unsafe _unsafe;
1156	<	static final long statusOffset;
1155	>	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1156	>	private static final long statusOffset =
1157	>	objectFieldOffset("status", ForkJoinTask.class);
1158
1159	<	static {
1159	>	private static long objectFieldOffset(String field, Class<?> klazz) {
1160		try {
1161	<	if (ForkJoinTask.class.getClassLoader() != null) {
1162	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1163	<	f.setAccessible(true);
1164	<	_unsafe = (Unsafe)f.get(null);
1165	<	}
1166	<	else
1167	<	_unsafe = Unsafe.getUnsafe();
1005	<	statusOffset = _unsafe.objectFieldOffset
1006	<	(ForkJoinTask.class.getDeclaredField("status"));
1007	<	} catch (Exception ex) { throw new Error(ex); }
1161	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
1162	>	} catch (NoSuchFieldException e) {
1163	>	// Convert Exception to corresponding Error
1164	>	NoSuchFieldError error = new NoSuchFieldError(field);
1165	>	error.initCause(e);
1166	>	throw error;
1167	>	}
1168		}
1169
1170	+	/**
1171	+	* Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
1172	+	* Replace with a simple call to Unsafe.getUnsafe when integrating
1173	+	* into a jdk.
1174	+	*
1175	+	* @return a sun.misc.Unsafe
1176	+	*/
1177	+	private static sun.misc.Unsafe getUnsafe() {
1178	+	try {
1179	+	return sun.misc.Unsafe.getUnsafe();
1180	+	} catch (SecurityException se) {
1181	+	try {
1182	+	return java.security.AccessController.doPrivileged
1183	+	(new java.security
1184	+	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1185	+	public sun.misc.Unsafe run() throws Exception {
1186	+	java.lang.reflect.Field f = sun.misc
1187	+	.Unsafe.class.getDeclaredField("theUnsafe");
1188	+	f.setAccessible(true);
1189	+	return (sun.misc.Unsafe) f.get(null);
1190	+	}});
1191	+	} catch (java.security.PrivilegedActionException e) {
1192	+	throw new RuntimeException("Could not initialize intrinsics",
1193	+	e.getCause());
1194	+	}
1195	+	}
1196	+	}
1197		}

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