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

Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.1 by dl, Tue Jan 6 14:30:31 2009 UTC vs.
Revision 1.50 by dl, Fri Jul 23 13:07:43 2010 UTC

#	Line 5 | Line 5
5		*/
6
7		package jsr166y;
8	<	import java.io.Serializable;
9	<	import java.util.*;
8	>
9		import java.util.concurrent.*;
10	<	import java.util.concurrent.atomic.*;
11	<	import sun.misc.Unsafe;
12	<	import java.lang.reflect.*;
10	>
11	>	import java.io.Serializable;
12	>	import java.util.Collection;
13	>	import java.util.Collections;
14	>	import java.util.List;
15	>	import java.util.RandomAccess;
16	>	import java.util.Map;
17	>	import java.util.WeakHashMap;
18
19		/**
20	<	* Abstract base class for tasks that run within a ForkJoinPool.  A
21	<	* ForkJoinTask is a thread-like entity that is much lighter weight
22	<	* than a normal thread.  Huge numbers of tasks and subtasks may be
23	<	* hosted by a small number of actual threads in a ForkJoinPool,
24	<	* at the price of some usage limitations.
20	>	* Abstract base class for tasks that run within a {@link ForkJoinPool}.
21	>	* A {@code ForkJoinTask} is a thread-like entity that is much
22	>	* lighter weight than a normal thread.  Huge numbers of tasks and
23	>	* subtasks may be hosted by a small number of actual threads in a
24	>	* ForkJoinPool, at the price of some usage limitations.
25	>	*
26	>	* <p>A "main" {@code ForkJoinTask} begins execution when submitted
27	>	* to a {@link ForkJoinPool}.  Once started, it will usually in turn
28	>	* start other subtasks.  As indicated by the name of this class,
29	>	* many programs using {@code ForkJoinTask} employ only methods
30	>	* {@link #fork} and {@link #join}, or derivatives such as {@link
31	>	* #invokeAll}.  However, this class also provides a number of other
32	>	* methods that can come into play in advanced usages, as well as
33	>	* extension mechanics that allow support of new forms of fork/join
34	>	* processing.
35	>	*
36	>	* <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}.
37	>	* The efficiency of {@code ForkJoinTask}s stems from a set of
38	>	* restrictions (that are only partially statically enforceable)
39	>	* reflecting their intended use as computational tasks calculating
40	>	* pure functions or operating on purely isolated objects.  The
41	>	* primary coordination mechanisms are {@link #fork}, that arranges
42	>	* asynchronous execution, and {@link #join}, that doesn't proceed
43	>	* until the task's result has been computed.  Computations should
44	>	* avoid {@code synchronized} methods or blocks, and should minimize
45	>	* other blocking synchronization apart from joining other tasks or
46	>	* using synchronizers such as Phasers that are advertised to
47	>	* cooperate with fork/join scheduling. Tasks should also not perform
48	>	* blocking IO, and should ideally access variables that are
49	>	* completely independent of those accessed by other running
50	>	* tasks. Minor breaches of these restrictions, for example using
51	>	* shared output streams, may be tolerable in practice, but frequent
52	>	* use may result in poor performance, and the potential to
53	>	* indefinitely stall if the number of threads not waiting for IO or
54	>	* other external synchronization becomes exhausted. This usage
55	>	* restriction is in part enforced by not permitting checked
56	>	* exceptions such as {@code IOExceptions} to be thrown. However,
57	>	* computations may still encounter unchecked exceptions, that are
58	>	* rethrown to callers attempting to join them. These exceptions may
59	>	* additionally include {@link RejectedExecutionException} stemming
60	>	* from internal resource exhaustion, such as failure to allocate
61	>	* internal task queues.
62	>	*
63	>	* <p>The primary method for awaiting completion and extracting
64	>	* results of a task is {@link #join}, but there are several variants:
65	>	* The {@link Future#get} methods support interruptible and/or timed
66	>	* waits for completion and report results using {@code Future}
67	>	* conventions. Method {@link #invoke} is semantically
68	>	* equivalent to {@code fork(); join()} but always attempts to begin
69	>	* execution in the current thread. The "<em>quiet</em>" forms of
70	>	* these methods do not extract results or report exceptions. These
71	>	* may be useful when a set of tasks are being executed, and you need
72	>	* to delay processing of results or exceptions until all complete.
73	>	* Method {@code invokeAll} (available in multiple versions)
74	>	* performs the most common form of parallel invocation: forking a set
75	>	* of tasks and joining them all.
76		*
77	<	* <p> ForkJoinTasks are forms of <tt>Futures</tt> supporting a
78	<	* limited range of use.  The "lightness" of ForkJoinTasks is due to a
79	<	* set of restrictions (that are only partially statically
80	<	* enforceable) reflecting their intended use as computational tasks
81	<	* calculating pure functions or operating on purely isolated objects.
82	<	* The primary coordination mechanisms supported for ForkJoinTasks are
83	<	* <tt>fork</tt>, that arranges asynchronous execution, and
84	<	* <tt>join</tt>, that doesn't proceed until the task's result has
85	<	* been computed. (Cancellation is also supported).  The computation
86	<	* defined in the <tt>compute</tt> method should avoid
87	<	* <tt>synchronized</tt> methods or blocks, and should minimize
33	<	* blocking synchronization apart from joining other tasks or using
34	<	* synchronizers such as Phasers that are advertised to cooperate with
35	<	* fork/join scheduling. Tasks should also not perform blocking IO,
36	<	* and should ideally access variables that are completely independent
37	<	* of those accessed by other running tasks. Minor breaches of these
38	<	* restrictions, for example using shared output streams, may be
39	<	* tolerable in practice, but frequent use may result in poor
40	<	* performance, and the potential to indefinitely stall if the number
41	<	* of threads not waiting for external synchronization becomes
42	<	* exhausted. This usage restriction is in part enforced by not
43	<	* permitting checked exceptions such as IOExceptions to be
44	<	* thrown. However, computations may still encounter unchecked
45	<	* exceptions, that are rethrown to callers attempting join
46	<	* them. These exceptions may additionally include
47	<	* RejectedExecutionExceptions stemming from internal resource
48	<	* exhaustion such as failure to allocate internal task queues.
77	>	* <p>The execution status of tasks may be queried at several levels
78	>	* of detail: {@link #isDone} is true if a task completed in any way
79	>	* (including the case where a task was cancelled without executing);
80	>	* {@link #isCompletedNormally} is true if a task completed without
81	>	* cancellation or encountering an exception; {@link #isCancelled} is
82	>	* true if the task was cancelled (in which case {@link #getException}
83	>	* returns a {@link java.util.concurrent.CancellationException}); and
84	>	* {@link #isCompletedAbnormally} is true if a task was either
85	>	* cancelled or encountered an exception, in which case {@link
86	>	* #getException} will return either the encountered exception or
87	>	* {@link java.util.concurrent.CancellationException}.
88		*
89	<	* <p> The <tt>ForkJoinTask</tt> class is not usually directly
90	<	* subclassed.  Instead, you subclass one of the abstract classes that
91	<	* support different styles of fork/join processing.  Normally, a
92	<	* concrete ForkJoinTask subclass declares fields comprising its
93	<	* parameters, established in a constructor, and then defines a
94	<	* <tt>compute</tt> method that somehow uses the control methods
95	<	* supplied by this base class. While these methods have
96	<	* <tt>public</tt> access, some of them may only be called from within
97	<	* other ForkJoinTasks. Attempts to invoke them in other contexts
98	<	* result in exceptions or errors including ClassCastException.  The
99	<	* only way to invoke a "main" driver task is to submit it to a
100	<	* ForkJoinPool. Once started, this will usually in turn start other
101	<	* subtasks.
89	>	* <p>The ForkJoinTask class is not usually directly subclassed.
90	>	* Instead, you subclass one of the abstract classes that support a
91	>	* particular style of fork/join processing, typically {@link
92	>	* RecursiveAction} for computations that do not return results, or
93	>	* {@link RecursiveTask} for those that do.  Normally, a concrete
94	>	* ForkJoinTask subclass declares fields comprising its parameters,
95	>	* established in a constructor, and then defines a {@code compute}
96	>	* method that somehow uses the control methods supplied by this base
97	>	* class. While these methods have {@code public} access (to allow
98	>	* instances of different task subclasses to call each other's
99	>	* methods), some of them may only be called from within other
100	>	* ForkJoinTasks (as may be determined using method {@link
101	>	* #inForkJoinPool}).  Attempts to invoke them in other contexts
102	>	* result in exceptions or errors, possibly including
103	>	* ClassCastException.
104		*
105	<	* <p>Most base support methods are <tt>final</tt> because their
106	<	* implementations are intrinsically tied to the underlying
107	<	* lightweight task scheduling framework, and so cannot be overridden.
108	<	* Developers creating new basic styles of fork/join processing should
109	<	* minimally implement protected methods <tt>exec</tt>,
110	<	* <tt>setRawResult</tt>, and <tt>getRawResult</tt>, while also
111	<	* introducing an abstract computational method that can be
112	<	* implemented in its subclasses. To support such extensions,
113	<	* instances of ForkJoinTasks maintain an atomically updated
73	<	* <tt>short</tt> representing user-defined control state.  Control
74	<	* state is guaranteed initially to be zero, and to be negative upon
75	<	* completion, but may otherwise be used for any other control
76	<	* purposes, such as maintaining join counts.  The {@link
77	<	* ForkJoinWorkerThread} class supports additional inspection and
78	<	* tuning methods that can be useful when developing extensions.
105	>	* <p>Most base support methods are {@code final}, to prevent
106	>	* overriding of implementations that are intrinsically tied to the
107	>	* underlying lightweight task scheduling framework.  Developers
108	>	* creating new basic styles of fork/join processing should minimally
109	>	* implement {@code protected} methods {@link #exec}, {@link
110	>	* #setRawResult}, and {@link #getRawResult}, while also introducing
111	>	* an abstract computational method that can be implemented in its
112	>	* subclasses, possibly relying on other {@code protected} methods
113	>	* provided by this class.
114		*
115		* <p>ForkJoinTasks should perform relatively small amounts of
116	<	* computations, othewise splitting into smaller tasks. As a very
117	<	* rough rule of thumb, a task should perform more than 100 and less
118	<	* than 10000 basic computational steps. If tasks are too big, then
119	<	* parellelism cannot improve throughput. If too small, then memory
120	<	* and internal task maintenance overhead may overwhelm processing.
116	>	* computation. Large tasks should be split into smaller subtasks,
117	>	* usually via recursive decomposition. As a very rough rule of thumb,
118	>	* a task should perform more than 100 and less than 10000 basic
119	>	* computational steps. If tasks are too big, then parallelism cannot
120	>	* improve throughput. If too small, then memory and internal task
121	>	* maintenance overhead may overwhelm processing.
122		*
123	<	* <p>ForkJoinTasks are <tt>Serializable</tt>, which enables them to
124	<	* be used in extensions such as remote execution frameworks. However,
125	<	* it is in general safe to serialize tasks only before or after, but
126	<	* not during execution. Serialization is not relied on during
127	<	* execution itself.
123	>	* <p>This class provides {@code adapt} methods for {@link Runnable}
124	>	* and {@link Callable}, that may be of use when mixing execution of
125	>	* {@code ForkJoinTasks} with other kinds of tasks. When all tasks are
126	>	* of this form, consider using a pool constructed in <em>asyncMode</em>.
127	>	*
128	>	* <p>ForkJoinTasks are {@code Serializable}, which enables them to be
129	>	* used in extensions such as remote execution frameworks. It is
130	>	* sensible to serialize tasks only before or after, but not during,
131	>	* execution. Serialization is not relied on during execution itself.
132	>	*
133	>	* @since 1.7
134	>	* @author Doug Lea
135		*/
136		public abstract class ForkJoinTask<V> implements Future<V>, Serializable {
137	<	/**
138	<	* Status field holding all run status. We pack this into a single
139	<	* int both to minimize footprint overhead and to ensure atomicity
140	<	* (updates are via CAS).
141	<	*
142	<	* Status is initially zero, and takes on nonnegative values until
143	<	* completed, upon which status holds COMPLETED. CANCELLED, or
144	<	* EXCEPTIONAL, which use the top 3 bits.  Tasks undergoing
145	<	* blocking waits by other threads have SIGNAL_MASK bits set --
146	<	* bit 15 for external (nonFJ) waits, and the rest a count of
147	<	* waiting FJ threads.  (This representation relies on
148	<	* ForkJoinPool max thread limits). Completion of a stolen task
149	<	* with SIGNAL_MASK bits set awakens waiter via notifyAll. Even
150	<	* though suboptimal for some purposes, we use basic builtin
151	<	* wait/notify to take advantage of "monitor inflation" in JVMs
152	<	* that we would otherwise need to emulate to avoid adding further
153	<	* per-task bookkeeping overhead. Note that bits 16-28 are
154	<	* currently unused. Also value 0x80000000 is available as spare
155	<	* completion value.
156	<	*/
157	<	volatile int status; // accessed directy by pool and workers
158	<
159	<	static final int COMPLETION_MASK      = 0xe0000000;
160	<	static final int NORMAL               = 0xe0000000; // == mask
161	<	static final int CANCELLED            = 0xc0000000;
162	<	static final int EXCEPTIONAL          = 0xa0000000;
163	<	static final int SIGNAL_MASK          = 0x0000ffff;
164	<	static final int INTERNAL_SIGNAL_MASK = 0x00007fff;
165	<	static final int EXTERNAL_SIGNAL      = 0x00008000; // top bit of low word
137	>
138	>	/*
139	>	* See the internal documentation of class ForkJoinPool for a
140	>	* general implementation overview.  ForkJoinTasks are mainly
141	>	* responsible for maintaining their "status" field amidst relays
142	>	* to methods in ForkJoinWorkerThread and ForkJoinPool. The
143	>	* methods of this class are more-or-less layered into (1) basic
144	>	* status maintenance (2) execution and awaiting completion (3)
145	>	* user-level methods that additionally report results. This is
146	>	* sometimes hard to see because this file orders exported methods
147	>	* in a way that flows well in javadocs.
148	>	*/
149	>
150	>	/*
151	>	* The status field holds run control status bits packed into a
152	>	* single int to minimize footprint and to ensure atomicity (via
153	>	* CAS).  Status is initially zero, and takes on nonnegative
154	>	* values until completed, upon which status holds value
155	>	* COMPLETED. CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking
156	>	* waits by other threads have the SIGNAL bit set.  Completion of
157	>	* a stolen task with SIGNAL set awakens any waiters via
158	>	* notifyAll. Even though suboptimal for some purposes, we use
159	>	* basic builtin wait/notify to take advantage of "monitor
160	>	* inflation" in JVMs that we would otherwise need to emulate to
161	>	* avoid adding further per-task bookkeeping overhead.  We want
162	>	* these monitors to be "fat", i.e., not use biasing or thin-lock
163	>	* techniques, so use some odd coding idioms that tend to avoid
164	>	* them.
165	>	*/
166	>
167	>	/** Run status of this task */
168	>	volatile int status; // accessed directly by pool and workers
169	>
170	>	private static final int NORMAL      = -1;
171	>	private static final int CANCELLED   = -2;
172	>	private static final int EXCEPTIONAL = -3;
173	>	private static final int SIGNAL      =  1;
174
175		/**
176		* Table of exceptions thrown by tasks, to enable reporting by
177		* callers. Because exceptions are rare, we don't directly keep
178	<	* them with task objects, but instead us a weak ref table.  Note
178	>	* them with task objects, but instead use a weak ref table.  Note
179		* that cancellation exceptions don't appear in the table, but are
180		* instead recorded as status values.
181	<	* Todo: Use ConcurrentReferenceHashMap
181	>	* TODO: Use ConcurrentReferenceHashMap
182		*/
183		static final Map<ForkJoinTask<?>, Throwable> exceptionMap =
184		Collections.synchronizedMap
185		(new WeakHashMap<ForkJoinTask<?>, Throwable>());
186
187	<	// within-package utilities
137	<
138	<	/**
139	<	* Get current worker thread, or null if not a worker thread
140	<	*/
141	<	static ForkJoinWorkerThread getWorker() {
142	<	Thread t = Thread.currentThread();
143	<	return ((t instanceof ForkJoinWorkerThread)?
144	<	(ForkJoinWorkerThread)t : null);
145	<	}
146	<
147	<	/**
148	<	* Get pool of current worker thread, or null if not a worker thread
149	<	*/
150	<	static ForkJoinPool getWorkerPool() {
151	<	Thread t = Thread.currentThread();
152	<	return ((t instanceof ForkJoinWorkerThread)?
153	<	((ForkJoinWorkerThread)t).pool : null);
154	<	}
155	<
156	<	final boolean casStatus(int cmp, int val) {
157	<	return _unsafe.compareAndSwapInt(this, statusOffset, cmp, val);
158	<	}
187	>	// Maintaining completion status
188
189		/**
190	<	* Workaround for not being able to rethrow unchecked exceptions.
191	<	*/
192	<	static void rethrowException(Throwable ex) {
164	<	if (ex != null)
165	<	_unsafe.throwException(ex);
166	<	}
167	<
168	<	// Setting completion status
169	<
170	<	/**
171	<	* Mark completion and wake up threads waiting to join this task.
190	>	* Marks completion and wakes up threads waiting to join this task,
191	>	* also clearing signal request bits.
192	>	*
193		* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
194	+	* @return status on exit
195		*/
196	<	final void setCompletion(int completion) {
197	<	ForkJoinPool pool = getWorkerPool();
198	<	if (pool != null) {
199	<	int s; // Clear signal bits while setting completion status
200	<	do;while ((s = status) >= 0 && !casStatus(s, completion));
201	<
202	<	if ((s & SIGNAL_MASK) != 0) {
181	<	if ((s &= INTERNAL_SIGNAL_MASK) != 0)
182	<	pool.updateRunningCount(s);
183	<	synchronized(this) { notifyAll(); }
196	>	private int setCompletion(int completion) {
197	>	int s;
198	>	while ((s = status) >= 0) {
199	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) {
200	>	if (s == SIGNAL)
201	>	synchronized (this) { notifyAll(); }
202	>	return completion;
203		}
204		}
205	<	else
187	<	externallySetCompletion(completion);
188	<	}
189	<
190	<	/**
191	<	* Version of setCompletion for non-FJ threads.  Leaves signal
192	<	* bits for unblocked threads to adjust, and always notifies.
193	<	*/
194	<	private void externallySetCompletion(int completion) {
195	<	int s;
196	<	do;while ((s = status) >= 0 &&
197	<	!casStatus(s, (s & SIGNAL_MASK) | completion));
198	<	synchronized(this) { notifyAll(); }
199	<	}
200	<
201	<	/**
202	<	* Sets status to indicate normal completion
203	<	*/
204	<	final void setNormalCompletion() {
205	<	// Try typical fast case -- single CAS, no signal, not already done.
206	<	// Manually expand casStatus to improve chances of inlining it
207	<	if (!_unsafe.compareAndSwapInt(this, statusOffset, 0, NORMAL))
208	<	setCompletion(NORMAL);
205	>	return s;
206		}
207
211	–	// internal waiting and notification
212	–
208		/**
209	<	* Performs the actual monitor wait for awaitDone
209	>	* Record exception and set exceptional completion
210	>	* @return status on exit
211		*/
212	<	private void doAwaitDone() {
213	<	// Minimize lock bias and in/de-flation effects by maximizing
214	<	// chances of waiting inside sync
219	<	try {
220	<	while (status >= 0)
221	<	synchronized(this) { if (status >= 0) wait(); }
222	<	} catch (InterruptedException ie) {
223	<	onInterruptedWait();
224	<	}
212	>	private int setExceptionalCompletion(Throwable rex) {
213	>	exceptionMap.put(this, rex);
214	>	return setCompletion(EXCEPTIONAL);
215		}
216
217		/**
218	<	* Performs the actual monitor wait for awaitDone
218	>	* Blocks a worker thread until completion. Called only by pool.
219		*/
220	<	private void doAwaitDone(long startTime, long nanos) {
221	<	synchronized(this) {
220	>	final void internalAwaitDone() {
221	>	int s;         // the odd construction reduces lock bias effects
222	>	while ((s = status) >= 0) {
223		try {
224	<	while (status >= 0) {
225	<	long nt = nanos - System.nanoTime() - startTime;
226	<	if (nt <= 0)
236	<	break;
237	<	wait(nt / 1000000, (int)(nt % 1000000));
224	>	synchronized(this) {
225	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s,SIGNAL))
226	>	wait();
227		}
228		} catch (InterruptedException ie) {
229	<	onInterruptedWait();
229	>	cancelIfTerminating();
230		}
231		}
232		}
233
245	–	// Awaiting completion
246	–
234		/**
235	<	* Sets status to indicate there is joiner, then waits for join,
236	<	* surrounded with pool notifications.
250	<	* @return status upon exit
235	>	* Blocks a non-worker-thread until completion.
236	>	* @return status on exit
237		*/
238	<	final int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) {
253	<	ForkJoinPool pool = w == null? null : w.pool;
238	>	private int externalAwaitDone() {
239		int s;
240		while ((s = status) >= 0) {
241	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
242	<	if (pool == null || !pool.preJoin(this, maintainParallelism))
243	<	doAwaitDone();
244	<	if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
245	<	adjustPoolCountsOnUnblock(pool);
246	<	break;
247	<	}
248	<	}
249	<	return s;
250	<	}
251	<
252	<	/**
253	<	* Timed version of awaitDone
269	<	* @return status upon exit
270	<	*/
271	<	final int awaitDone(ForkJoinWorkerThread w, long nanos) {
272	<	ForkJoinPool pool = w == null? null : w.pool;
273	<	int s;
274	<	while ((s = status) >= 0) {
275	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
276	<	long startTime = System.nanoTime();
277	<	if (pool == null || !pool.preJoin(this, false))
278	<	doAwaitDone(startTime, nanos);
279	<	if ((s = status) >= 0) {
280	<	adjustPoolCountsOnCancelledWait(pool);
281	<	s = status;
241	>	synchronized(this) {
242	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, SIGNAL)){
243	>	boolean interrupted = false;
244	>	while ((s = status) >= 0) {
245	>	try {
246	>	wait();
247	>	} catch (InterruptedException ie) {
248	>	interrupted = true;
249	>	}
250	>	}
251	>	if (interrupted)
252	>	Thread.currentThread().interrupt();
253	>	break;
254		}
283	–	if (s < 0 && (s & INTERNAL_SIGNAL_MASK) != 0)
284	–	adjustPoolCountsOnUnblock(pool);
285	–	break;
255		}
256		}
257		return s;
258		}
259
260		/**
261	<	* Notify pool that thread is unblocked. Called by signalled
262	<	* threads when woken by non-FJ threads (which is atypical).
261	>	* Unless done, calls exec and records status if completed, but
262	>	* doesn't wait for completion otherwise. Primary execution method
263	>	* for ForkJoinWorkerThread.
264		*/
265	<	private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
266	<	int s;
267	<	do;while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
268	<	if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
269	<	pool.updateRunningCount(s);
265	>	final void tryExec() {
266	>	try {
267	>	if (status < 0 || !exec())
268	>	return;
269	>	} catch (Throwable rex) {
270	>	setExceptionalCompletion(rex);
271	>	return;
272	>	}
273	>	setCompletion(NORMAL); // must be outside try block
274		}
275
276		/**
277	<	* Notify pool to adjust counts on cancelled or timed out wait
277	>	* If not done and this task is next in worker queue, runs it,
278	>	* else waits for it.
279	>	* @return status on exit
280		*/
281	<	private void adjustPoolCountsOnCancelledWait(ForkJoinPool pool) {
282	<	if (pool != null) {
283	<	int s;
284	<	while ((s = status) >= 0 && (s & INTERNAL_SIGNAL_MASK) != 0) {
309	<	if (casStatus(s, s - 1)) {
310	<	pool.updateRunningCount(1);
311	<	break;
312	<	}
313	<	}
314	<	}
315	<	}
316	<
317	<	private void onInterruptedWait() {
281	>	private int doJoin() {
282	>	int stat;
283	>	if ((stat = status) < 0)
284	>	return stat;
285		Thread t = Thread.currentThread();
286	+	ForkJoinWorkerThread w;
287		if (t instanceof ForkJoinWorkerThread) {
288	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)t;
289	<	if (w.isTerminating())
290	<	cancelIgnoreExceptions();
291	<	}
292	<	else { // re-interrupt
293	<	try {
294	<	t.interrupt();
295	<	} catch (SecurityException ignore) {
288	>	if ((w = (ForkJoinWorkerThread) t).unpushTask(this)) {
289	>	boolean completed;
290	>	try {
291	>	completed = exec();
292	>	} catch (Throwable rex) {
293	>	return setExceptionalCompletion(rex);
294	>	}
295	>	if (completed)
296	>	return setCompletion(NORMAL);
297		}
298	+	return w.joinTask(this);
299		}
300	+	return externalAwaitDone();
301		}
302
332	–	// Recording and reporting exceptions
333	–
334	–	private void setDoneExceptionally(Throwable rex) {
335	–	exceptionMap.put(this, rex);
336	–	setCompletion(EXCEPTIONAL);
337	–	}
338	–
339	–	/**
340	–	* Throws the exception associated with status s;
341	–	* @throws the exception
342	–	*/
343	–	private void reportException(int s) {
344	–	if ((s &= COMPLETION_MASK) < NORMAL) {
345	–	if (s == CANCELLED)
346	–	throw new CancellationException();
347	–	else
348	–	rethrowException(exceptionMap.get(this));
349	–	}
350	–	}
351	–
352	–	/**
353	–	* Returns result or throws exception using j.u.c.Future conventions
354	–	* Only call when isDone known to be true.
355	–	*/
356	–	private V reportFutureResult()
357	–	throws ExecutionException, InterruptedException {
358	–	int s = status & COMPLETION_MASK;
359	–	if (s < NORMAL) {
360	–	Throwable ex;
361	–	if (s == CANCELLED)
362	–	throw new CancellationException();
363	–	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
364	–	throw new ExecutionException(ex);
365	–	if (Thread.interrupted())
366	–	throw new InterruptedException();
367	–	}
368	–	return getRawResult();
369	–	}
370	–
371	–	/**
372	–	* Returns result or throws exception using j.u.c.Future conventions
373	–	* with timeouts
374	–	*/
375	–	private V reportTimedFutureResult()
376	–	throws InterruptedException, ExecutionException, TimeoutException {
377	–	Throwable ex;
378	–	int s = status & COMPLETION_MASK;
379	–	if (s == NORMAL)
380	–	return getRawResult();
381	–	if (s == CANCELLED)
382	–	throw new CancellationException();
383	–	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
384	–	throw new ExecutionException(ex);
385	–	if (Thread.interrupted())
386	–	throw new InterruptedException();
387	–	throw new TimeoutException();
388	–	}
389	–
390	–	// internal execution methods
391	–
303		/**
304	<	* Calls exec, recording completion, and rethrowing exception if
305	<	* encountered. Caller should normally check status before calling
306	<	* @return true if completed normally
304	>	* Unless done, calls exec and records status if completed, or
305	>	* waits for completion otherwise.
306	>	* @return status on exit
307		*/
308	<	private boolean tryExec() {
309	<	try { // try block must contain only call to exec
310	<	if (!exec())
311	<	return false;
401	<	} catch (Throwable rex) {
402	<	setDoneExceptionally(rex);
403	<	rethrowException(rex);
404	<	return false; // not reached
405	<	}
406	<	setNormalCompletion();
407	<	return true;
408	<	}
409	<
410	<	/**
411	<	* Main execution method used by worker threads. Invokes
412	<	* base computation unless already complete
413	<	*/
414	<	final void quietlyExec() {
415	<	if (status >= 0) {
308	>	private int doInvoke() {
309	>	int stat;
310	>	if ((stat = status) >= 0) {
311	>	boolean completed;
312		try {
313	<	if (!exec())
314	<	return;
315	<	} catch(Throwable rex) {
420	<	setDoneExceptionally(rex);
421	<	return;
313	>	completed = exec();
314	>	} catch (Throwable rex) {
315	>	return setExceptionalCompletion(rex);
316		}
317	<	setNormalCompletion();
424	<	}
425	<	}
426	<
427	<	/**
428	<	* Calls exec, recording but not rethrowing exception
429	<	* Caller should normally check status before calling
430	<	* @return true if completed normally
431	<	*/
432	<	private boolean tryQuietlyInvoke() {
433	<	try {
434	<	if (!exec())
435	<	return false;
436	<	} catch (Throwable rex) {
437	<	setDoneExceptionally(rex);
438	<	return false;
317	>	stat = completed ? setCompletion(NORMAL) : doJoin();
318		}
319	<	setNormalCompletion();
441	<	return true;
319	>	return stat;
320		}
321
322		/**
323	<	* Cancel, ignoring any exceptions it throws
323	>	* Returns result or throws exception associated with given status.
324	>	* @param s the status
325		*/
326	<	final void cancelIgnoreExceptions() {
327	<	try {
328	<	cancel(false);
329	<	} catch(Throwable ignore) {
330	<	}
326	>	private V reportResult(int s) {
327	>	Throwable ex;
328	>	if (s < NORMAL && (ex = getException()) != null)
329	>	UNSAFE.throwException(ex);
330	>	return getRawResult();
331		}
332
333		// public methods
#	Line 456 | Line 335 | public abstract class ForkJoinTask<V> im
335		/**
336		* Arranges to asynchronously execute this task.  While it is not
337		* necessarily enforced, it is a usage error to fork a task more
338	<	* than once unless it has completed and been reinitialized.  This
339	<	* method may be invoked only from within other ForkJoinTask
340	<	* computations. Attempts to invoke in other contexts result in
341	<	* exceptions or errors including ClassCastException.
338	>	* than once unless it has completed and been reinitialized.
339	>	* Subsequent modifications to the state of this task or any data
340	>	* it operates on are not necessarily consistently observable by
341	>	* any thread other than the one executing it unless preceded by a
342	>	* call to {@link #join} or related methods, or a call to {@link
343	>	* #isDone} returning {@code true}.
344	>	*
345	>	* <p>This method may be invoked only from within {@code
346	>	* ForkJoinTask} computations (as may be determined using method
347	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
348	>	* result in exceptions or errors, possibly including {@code
349	>	* ClassCastException}.
350	>	*
351	>	* @return {@code this}, to simplify usage
352		*/
353	<	public final void fork() {
354	<	((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this);
353	>	public final ForkJoinTask<V> fork() {
354	>	((ForkJoinWorkerThread) Thread.currentThread())
355	>	.pushTask(this);
356	>	return this;
357		}
358
359		/**
360	<	* Returns the result of the computation when it is ready.
361	<	* This method differs from <tt>get</tt> in that abnormal
362	<	* completion results in RuntimeExceptions or Errors, not
363	<	* ExecutionExceptions.
360	>	* Returns the result of the computation when it {@link #isDone is done}.
361	>	* This method differs from {@link #get()} in that
362	>	* abnormal completion results in {@code RuntimeException} or
363	>	* {@code Error}, not {@code ExecutionException}.
364		*
365		* @return the computed result
366		*/
367		public final V join() {
368	<	ForkJoinWorkerThread w = getWorker();
478	<	if (w == null || status < 0 || !w.unpushTask(this) || !tryExec())
479	<	reportException(awaitDone(w, true));
480	<	return getRawResult();
481	<	}
482	<
483	<	public final V get() throws InterruptedException, ExecutionException {
484	<	ForkJoinWorkerThread w = getWorker();
485	<	if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
486	<	awaitDone(w, true);
487	<	return reportFutureResult();
488	<	}
489	<
490	<	public final V get(long timeout, TimeUnit unit)
491	<	throws InterruptedException, ExecutionException, TimeoutException {
492	<	ForkJoinWorkerThread w = getWorker();
493	<	if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke())
494	<	awaitDone(w, unit.toNanos(timeout));
495	<	return reportTimedFutureResult();
368	>	return reportResult(doJoin());
369		}
370
371		/**
372	<	* Possibly executes other tasks until this task is ready, then
373	<	* returns the result of the computation.  This method may be more
374	<	* efficient than <tt>join</tt>, but is only applicable when there
375	<	* are no potemtial dependencies between continuation of the
503	<	* current task and that of any other task that might be executed
504	<	* while helping. (This usually holds for pure divide-and-conquer
505	<	* tasks).
372	>	* Commences performing this task, awaits its completion if
373	>	* necessary, and return its result, or throws an (unchecked)
374	>	* exception if the underlying computation did so.
375	>	*
376		* @return the computed result
377		*/
378	<	public final V helpJoin() {
379	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread());
510	<	if (status < 0 || !w.unpushTask(this) || !tryExec())
511	<	reportException(w.helpJoinTask(this));
512	<	return getRawResult();
378	>	public final V invoke() {
379	>	return reportResult(doInvoke());
380		}
381
382		/**
383	<	* Performs this task, awaits its completion if necessary, and
384	<	* return its result.
385	<	* @throws Throwable (a RuntimeException, Error, or unchecked
386	<	* exception) if the underlying computation did so.
387	<	* @return the computed result
383	>	* Forks the given tasks, returning when {@code isDone} holds for
384	>	* each task or an (unchecked) exception is encountered, in which
385	>	* case the exception is rethrown.  If either task encounters an
386	>	* exception, the other one may be, but is not guaranteed to be,
387	>	* cancelled.  If both tasks throw an exception, then this method
388	>	* throws one of them.  The individual status of each task may be
389	>	* checked using {@link #getException()} and related methods.
390	>	*
391	>	* <p>This method may be invoked only from within {@code
392	>	* ForkJoinTask} computations (as may be determined using method
393	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
394	>	* result in exceptions or errors, possibly including {@code
395	>	* ClassCastException}.
396	>	*
397	>	* @param t1 the first task
398	>	* @param t2 the second task
399	>	* @throws NullPointerException if any task is null
400		*/
401	<	public final V invoke() {
402	<	if (status >= 0 && tryExec())
403	<	return getRawResult();
404	<	else
526	<	return join();
401	>	public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) {
402	>	t2.fork();
403	>	t1.invoke();
404	>	t2.join();
405		}
406
407		/**
408	<	* Joins this task, without returning its result or throwing an
409	<	* exception. This method may be useful when processing
410	<	* collections of tasks when some have been cancelled or otherwise
411	<	* known to have aborted.
408	>	* Forks the given tasks, returning when {@code isDone} holds for
409	>	* each task or an (unchecked) exception is encountered, in which
410	>	* case the exception is rethrown. If any task encounters an
411	>	* exception, others may be, but are not guaranteed to be,
412	>	* cancelled.  If more than one task encounters an exception, then
413	>	* this method throws any one of these exceptions.  The individual
414	>	* status of each task may be checked using {@link #getException()}
415	>	* and related methods.
416	>	*
417	>	* <p>This method may be invoked only from within {@code
418	>	* ForkJoinTask} computations (as may be determined using method
419	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
420	>	* result in exceptions or errors, possibly including {@code
421	>	* ClassCastException}.
422	>	*
423	>	* @param tasks the tasks
424	>	* @throws NullPointerException if any task is null
425		*/
426	<	public final void quietlyJoin() {
427	<	if (status >= 0) {
428	<	ForkJoinWorkerThread w = getWorker();
429	<	if (w == null || !w.unpushTask(this) || !tryQuietlyInvoke())
430	<	awaitDone(w, true);
426	>	public static void invokeAll(ForkJoinTask<?>... tasks) {
427	>	Throwable ex = null;
428	>	int last = tasks.length - 1;
429	>	for (int i = last; i >= 0; --i) {
430	>	ForkJoinTask<?> t = tasks[i];
431	>	if (t == null) {
432	>	if (ex == null)
433	>	ex = new NullPointerException();
434	>	}
435	>	else if (i != 0)
436	>	t.fork();
437	>	else if (t.doInvoke() < NORMAL && ex == null)
438	>	ex = t.getException();
439	>	}
440	>	for (int i = 1; i <= last; ++i) {
441	>	ForkJoinTask<?> t = tasks[i];
442	>	if (t != null) {
443	>	if (ex != null)
444	>	t.cancel(false);
445	>	else if (t.doJoin() < NORMAL && ex == null)
446	>	ex = t.getException();
447	>	}
448		}
449	+	if (ex != null)
450	+	UNSAFE.throwException(ex);
451		}
452
453		/**
454	<	* Possibly executes other tasks until this task is ready.
454	>	* Forks all tasks in the specified collection, returning when
455	>	* {@code isDone} holds for each task or an (unchecked) exception
456	>	* is encountered.  If any task encounters an exception, others
457	>	* may be, but are not guaranteed to be, cancelled.  If more than
458	>	* one task encounters an exception, then this method throws any
459	>	* one of these exceptions.  The individual status of each task
460	>	* may be checked using {@link #getException()} and related
461	>	* methods.  The behavior of this operation is undefined if the
462	>	* specified collection is modified while the operation is in
463	>	* progress.
464	>	*
465	>	* <p>This method may be invoked only from within {@code
466	>	* ForkJoinTask} computations (as may be determined using method
467	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
468	>	* result in exceptions or errors, possibly including {@code
469	>	* ClassCastException}.
470	>	*
471	>	* @param tasks the collection of tasks
472	>	* @return the tasks argument, to simplify usage
473	>	* @throws NullPointerException if tasks or any element are null
474		*/
475	<	public final void quietlyHelpJoin() {
476	<	if (status >= 0) {
477	<	ForkJoinWorkerThread w =
478	<	(ForkJoinWorkerThread)(Thread.currentThread());
479	<	if (!w.unpushTask(this) || !tryQuietlyInvoke())
480	<	w.helpJoinTask(this);
475	>	public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) {
476	>	if (!(tasks instanceof RandomAccess) || !(tasks instanceof List<?>)) {
477	>	invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()]));
478	>	return tasks;
479	>	}
480	>	@SuppressWarnings("unchecked")
481	>	List<? extends ForkJoinTask<?>> ts =
482	>	(List<? extends ForkJoinTask<?>>) tasks;
483	>	Throwable ex = null;
484	>	int last = ts.size() - 1;
485	>	for (int i = last; i >= 0; --i) {
486	>	ForkJoinTask<?> t = ts.get(i);
487	>	if (t == null) {
488	>	if (ex == null)
489	>	ex = new NullPointerException();
490	>	}
491	>	else if (i != 0)
492	>	t.fork();
493	>	else if (t.doInvoke() < NORMAL && ex == null)
494	>	ex = t.getException();
495	>	}
496	>	for (int i = 1; i <= last; ++i) {
497	>	ForkJoinTask<?> t = ts.get(i);
498	>	if (t != null) {
499	>	if (ex != null)
500	>	t.cancel(false);
501	>	else if (t.doJoin() < NORMAL && ex == null)
502	>	ex = t.getException();
503	>	}
504		}
505	+	if (ex != null)
506	+	UNSAFE.throwException(ex);
507	+	return tasks;
508		}
509
510		/**
511	<	* Performs this task and awaits its completion if necessary,
512	<	* without returning its result or throwing an exception. This
513	<	* method may be useful when processing collections of tasks when
514	<	* some have been cancelled or otherwise known to have aborted.
511	>	* Attempts to cancel execution of this task. This attempt will
512	>	* fail if the task has already completed, has already been
513	>	* cancelled, or could not be cancelled for some other reason. If
514	>	* successful, and this task has not started when cancel is
515	>	* called, execution of this task is suppressed, {@link
516	>	* #isCancelled} will report true, and {@link #join} will result
517	>	* in a {@code CancellationException} being thrown.
518	>	*
519	>	* <p>This method may be overridden in subclasses, but if so, must
520	>	* still ensure that these minimal properties hold. In particular,
521	>	* the {@code cancel} method itself must not throw exceptions.
522	>	*
523	>	* <p>This method is designed to be invoked by <em>other</em>
524	>	* tasks. To terminate the current task, you can just return or
525	>	* throw an unchecked exception from its computation method, or
526	>	* invoke {@link #completeExceptionally}.
527	>	*
528	>	* @param mayInterruptIfRunning this value is ignored in the
529	>	* default implementation because tasks are not
530	>	* cancelled via interruption
531	>	*
532	>	* @return {@code true} if this task is now cancelled
533		*/
534	<	public final void quietlyInvoke() {
535	<	if (status >= 0 && !tryQuietlyInvoke())
563	<	quietlyJoin();
534	>	public boolean cancel(boolean mayInterruptIfRunning) {
535	>	return setCompletion(CANCELLED) == CANCELLED;
536		}
537
538		/**
539	<	* Returns true if the computation performed by this task has
540	<	* completed (or has been cancelled).
569	<	* @return true if this computation has completed
539	>	* Cancels, ignoring any exceptions it throws. Used during worker
540	>	* and pool shutdown.
541		*/
542	<	public final boolean isDone() {
543	<	return status < 0;
542	>	final void cancelIgnoringExceptions() {
543	>	try {
544	>	cancel(false);
545	>	} catch (Throwable ignore) {
546	>	}
547		}
548
549		/**
550	<	* Returns true if this task was cancelled.
577	<	* @return true if this task was cancelled
550	>	* Cancels ignoring exceptions if worker is terminating
551		*/
552	+	final void cancelIfTerminating() {
553	+	Thread t = Thread.currentThread();
554	+	if ((t instanceof ForkJoinWorkerThread) &&
555	+	((ForkJoinWorkerThread) t).isTerminating()) {
556	+	try {
557	+	cancel(false);
558	+	} catch (Throwable ignore) {
559	+	}
560	+	}
561	+	}
562	+
563	+	public final boolean isDone() {
564	+	return status < 0;
565	+	}
566	+
567		public final boolean isCancelled() {
568	<	return (status & COMPLETION_MASK) == CANCELLED;
568	>	return status == CANCELLED;
569		}
570
571		/**
572	<	* Returns true if this task threw an exception or was cancelled
573	<	* @return true if this task threw an exception or was cancelled
572	>	* Returns {@code true} if this task threw an exception or was cancelled.
573	>	*
574	>	* @return {@code true} if this task threw an exception or was cancelled
575		*/
576	<	public final boolean completedAbnormally() {
577	<	return (status & COMPLETION_MASK) < NORMAL;
576	>	public final boolean isCompletedAbnormally() {
577	>	return status < NORMAL;
578		}
579
580		/**
581	<	* Returns the exception thrown by the base computation, or a
582	<	* CancellationException if cancelled, or null if none or if the
583	<	* method has not yet completed.
584	<	* @return the exception, or null if none
581	>	* Returns {@code true} if this task completed without throwing an
582	>	* exception and was not cancelled.
583	>	*
584	>	* @return {@code true} if this task completed without throwing an
585	>	* exception and was not cancelled
586		*/
587	<	public final Throwable getException() {
588	<	int s = status & COMPLETION_MASK;
599	<	if (s >= NORMAL)
600	<	return null;
601	<	if (s == CANCELLED)
602	<	return new CancellationException();
603	<	return exceptionMap.get(this);
587	>	public final boolean isCompletedNormally() {
588	>	return status == NORMAL;
589		}
590
591		/**
592	<	* Asserts that the results of this task's computation will not be
593	<	* used. If a cancellation occurs before this task is processed,
594	<	* then its <tt>compute</tt> method will not be executed,
610	<	* <tt>isCancelled</tt> will report true, and <tt>join</tt> will
611	<	* result in a CancellationException being thrown. Otherwise, when
612	<	* cancellation races with completion, there are no guarantees
613	<	* about whether <tt>isCancelled</tt> will report true, whether
614	<	* <tt>join</tt> will return normally or via an exception, or
615	<	* whether these behaviors will remain consistent upon repeated
616	<	* invocation.
617	<	*
618	<	* <p>This method may be overridden in subclasses, but if so, must
619	<	* still ensure that these minimal properties hold. In particular,
620	<	* the cancel method itself must not throw exceptions.
621	<	*
622	<	* <p> This method is designed to be invoked by <em>other</em>
623	<	* tasks. To terminate the current task, you can just return or
624	<	* throw an unchecked exception from its computation method, or
625	<	* invoke <tt>completeExceptionally(someException)</tt>.
626	<	*
627	<	* @param mayInterruptIfRunning this value is ignored in the
628	<	* default implementation because tasks are not in general
629	<	* cancelled via interruption.
592	>	* Returns the exception thrown by the base computation, or a
593	>	* {@code CancellationException} if cancelled, or {@code null} if
594	>	* none or if the method has not yet completed.
595		*
596	<	* @return true if this task is now cancelled
596	>	* @return the exception, or {@code null} if none
597		*/
598	<	public boolean cancel(boolean mayInterruptIfRunning) {
599	<	setCompletion(CANCELLED);
600	<	return (status & COMPLETION_MASK) == CANCELLED;
598	>	public final Throwable getException() {
599	>	int s = status;
600	>	return ((s >= NORMAL)    ? null :
601	>	(s == CANCELLED) ? new CancellationException() :
602	>	exceptionMap.get(this));
603		}
604
605		/**
606		* Completes this task abnormally, and if not already aborted or
607		* cancelled, causes it to throw the given exception upon
608	<	* <tt>join</tt> and related operations. This method may be used
608	>	* {@code join} and related operations. This method may be used
609		* to induce exceptions in asynchronous tasks, or to force
610	<	* completion of tasks that would not otherwise complete.  This
611	<	* method is overridable, but overridden versions must invoke
612	<	* <tt>super</tt> implementation to maintain guarantees.
613	<	* @param ex the exception to throw. If this exception is
614	<	* not a RuntimeException or Error, the actual exception thrown
615	<	* will be a RuntimeException with cause ex.
610	>	* completion of tasks that would not otherwise complete.  Its use
611	>	* in other situations is discouraged.  This method is
612	>	* overridable, but overridden versions must invoke {@code super}
613	>	* implementation to maintain guarantees.
614	>	*
615	>	* @param ex the exception to throw. If this exception is not a
616	>	* {@code RuntimeException} or {@code Error}, the actual exception
617	>	* thrown will be a {@code RuntimeException} with cause {@code ex}.
618		*/
619		public void completeExceptionally(Throwable ex) {
620	<	setDoneExceptionally((ex instanceof RuntimeException) ||
621	<	(ex instanceof Error)? ex :
622	<	new RuntimeException(ex));
620	>	setExceptionalCompletion((ex instanceof RuntimeException) ||
621	>	(ex instanceof Error) ? ex :
622	>	new RuntimeException(ex));
623		}
624
625		/**
626		* Completes this task, and if not already aborted or cancelled,
627	<	* returning a <tt>null</tt> result upon <tt>join</tt> and related
627	>	* returning a {@code null} result upon {@code join} and related
628		* operations. This method may be used to provide results for
629		* asynchronous tasks, or to provide alternative handling for
630	<	* tasks that would not otherwise complete normally.
630	>	* tasks that would not otherwise complete normally. Its use in
631	>	* other situations is discouraged. This method is
632	>	* overridable, but overridden versions must invoke {@code super}
633	>	* implementation to maintain guarantees.
634		*
635	<	* @param value the result value for this task.
635	>	* @param value the result value for this task
636		*/
637		public void complete(V value) {
638		try {
639		setRawResult(value);
640	<	} catch(Throwable rex) {
641	<	setDoneExceptionally(rex);
640	>	} catch (Throwable rex) {
641	>	setExceptionalCompletion(rex);
642		return;
643		}
644	<	setNormalCompletion();
644	>	setCompletion(NORMAL);
645	>	}
646	>
647	>	public final V get() throws InterruptedException, ExecutionException {
648	>	int s = doJoin();
649	>	if (Thread.interrupted())
650	>	throw new InterruptedException();
651	>	if (s < NORMAL) {
652	>	Throwable ex;
653	>	if (s == CANCELLED)
654	>	throw new CancellationException();
655	>	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
656	>	throw new ExecutionException(ex);
657	>	}
658	>	return getRawResult();
659	>	}
660	>
661	>	public final V get(long timeout, TimeUnit unit)
662	>	throws InterruptedException, ExecutionException, TimeoutException {
663	>	Thread t = Thread.currentThread();
664	>	ForkJoinPool pool;
665	>	if (t instanceof ForkJoinWorkerThread) {
666	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) t;
667	>	if (status >= 0 && w.unpushTask(this))
668	>	tryExec();
669	>	pool = w.pool;
670	>	}
671	>	else
672	>	pool = null;
673	>	/*
674	>	* Timed wait loop intermixes cases for fj (pool != null) and
675	>	* non FJ threads. For FJ, decrement pool count but don't try
676	>	* for replacement; increment count on completion. For non-FJ,
677	>	* deal with interrupts. This is messy, but a little less so
678	>	* than is splitting the FJ and nonFJ cases.
679	>	*/
680	>	boolean interrupted = false;
681	>	boolean dec = false; // true if pool count decremented
682	>	for (;;) {
683	>	if (Thread.interrupted() && pool == null) {
684	>	interrupted = true;
685	>	break;
686	>	}
687	>	int s = status;
688	>	if (s < 0)
689	>	break;
690	>	if (UNSAFE.compareAndSwapInt(this, statusOffset,
691	>	s, s | SIGNAL)) {
692	>	long startTime = System.nanoTime();
693	>	long nanos = unit.toNanos(timeout);
694	>	long nt; // wait time
695	>	while (status >= 0 &&
696	>	(nt = nanos - (System.nanoTime() - startTime)) > 0) {
697	>	if (pool != null && !dec)
698	>	dec = pool.tryDecrementRunningCount();
699	>	else {
700	>	long ms = nt / 1000000;
701	>	int ns = (int) (nt % 1000000);
702	>	try {
703	>	synchronized(this) {
704	>	if (status >= 0)
705	>	wait(ms, ns);
706	>	}
707	>	} catch (InterruptedException ie) {
708	>	if (pool != null)
709	>	cancelIfTerminating();
710	>	else {
711	>	interrupted = true;
712	>	break;
713	>	}
714	>	}
715	>	}
716	>	}
717	>	break;
718	>	}
719	>	}
720	>	if (pool != null && dec)
721	>	pool.incrementRunningCount();
722	>	if (interrupted)
723	>	throw new InterruptedException();
724	>	int es = status;
725	>	if (es != NORMAL) {
726	>	Throwable ex;
727	>	if (es == CANCELLED)
728	>	throw new CancellationException();
729	>	if (es == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
730	>	throw new ExecutionException(ex);
731	>	throw new TimeoutException();
732	>	}
733	>	return getRawResult();
734	>	}
735	>
736	>	/**
737	>	* Joins this task, without returning its result or throwing an
738	>	* exception. This method may be useful when processing
739	>	* collections of tasks when some have been cancelled or otherwise
740	>	* known to have aborted.
741	>	*/
742	>	public final void quietlyJoin() {
743	>	doJoin();
744	>	}
745	>
746	>	/**
747	>	* Commences performing this task and awaits its completion if
748	>	* necessary, without returning its result or throwing an
749	>	* exception. This method may be useful when processing
750	>	* collections of tasks when some have been cancelled or otherwise
751	>	* known to have aborted.
752	>	*/
753	>	public final void quietlyInvoke() {
754	>	doInvoke();
755	>	}
756	>
757	>	/**
758	>	* Possibly executes tasks until the pool hosting the current task
759	>	* {@link ForkJoinPool#isQuiescent is quiescent}. This method may
760	>	* be of use in designs in which many tasks are forked, but none
761	>	* are explicitly joined, instead executing them until all are
762	>	* processed.
763	>	*
764	>	* <p>This method may be invoked only from within {@code
765	>	* ForkJoinTask} computations (as may be determined using method
766	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
767	>	* result in exceptions or errors, possibly including {@code
768	>	* ClassCastException}.
769	>	*/
770	>	public static void helpQuiesce() {
771	>	((ForkJoinWorkerThread) Thread.currentThread())
772	>	.helpQuiescePool();
773		}
774
775		/**
776		* Resets the internal bookkeeping state of this task, allowing a
777	<	* subsequent <tt>fork</tt>. This method allows repeated reuse of
777	>	* subsequent {@code fork}. This method allows repeated reuse of
778		* this task, but only if reuse occurs when this task has either
779		* never been forked, or has been forked, then completed and all
780		* outstanding joins of this task have also completed. Effects
781	<	* under any other usage conditions are not guaranteed, and are
782	<	* almost surely wrong. This method may be useful when executing
781	>	* under any other usage conditions are not guaranteed.
782	>	* This method may be useful when executing
783		* pre-constructed trees of subtasks in loops.
784		*/
785		public void reinitialize() {
786	<	if ((status & COMPLETION_MASK) == EXCEPTIONAL)
786	>	if (status == EXCEPTIONAL)
787		exceptionMap.remove(this);
788		status = 0;
789		}
790
791		/**
792	<	* Tries to unschedule this task for execution. This method will
793	<	* typically succeed if this task is the next task that would be
794	<	* executed by the current thread, and will typically fail (return
795	<	* false) otherwise. This method may be useful when arranging
796	<	* faster local processing of tasks that could have been, but were
697	<	* not, stolen.
698	<	* @return true if unforked
699	<	*/
700	<	public boolean tryUnfork() {
701	<	return ((ForkJoinWorkerThread)(Thread.currentThread())).unpushTask(this);
702	<	}
703	<
704	<	/**
705	<	* Forks both tasks, returning when <tt>isDone</tt> holds for both
706	<	* of them or an exception is encountered. This method may be
707	<	* invoked only from within other ForkJoinTask
708	<	* computations. Attempts to invoke in other contexts result in
709	<	* exceptions or errors including ClassCastException.
710	<	* @param t1 one task
711	<	* @param t2 the other task
712	<	* @throws NullPointerException if t1 or t2 are null
713	<	* @throws RuntimeException or Error if either task did so.
792	>	* Returns the pool hosting the current task execution, or null
793	>	* if this task is executing outside of any ForkJoinPool.
794	>	*
795	>	* @see #inForkJoinPool
796	>	* @return the pool, or {@code null} if none
797		*/
798	<	public static void invokeAll(ForkJoinTask<?>t1, ForkJoinTask<?> t2) {
799	<	t2.fork();
800	<	t1.invoke();
801	<	t2.join();
798	>	public static ForkJoinPool getPool() {
799	>	Thread t = Thread.currentThread();
800	>	return (t instanceof ForkJoinWorkerThread) ?
801	>	((ForkJoinWorkerThread) t).pool : null;
802		}
803
804		/**
805	<	* Forks the given tasks, returning when <tt>isDone</tt> holds for
806	<	* all of them. If any task encounters an exception, others may be
807	<	* cancelled.  This method may be invoked only from within other
808	<	* ForkJoinTask computations. Attempts to invoke in other contexts
809	<	* result in exceptions or errors including ClassCastException.
727	<	* @param tasks the array of tasks
728	<	* @throws NullPointerException if tasks or any element are null.
729	<	* @throws RuntimeException or Error if any task did so.
805	>	* Returns {@code true} if the current thread is executing as a
806	>	* ForkJoinPool computation.
807	>	*
808	>	* @return {@code true} if the current thread is executing as a
809	>	* ForkJoinPool computation, or false otherwise
810		*/
811	<	public static void invokeAll(ForkJoinTask<?>... tasks) {
812	<	Throwable ex = null;
733	<	int last = tasks.length - 1;
734	<	for (int i = last; i >= 0; --i) {
735	<	ForkJoinTask<?> t = tasks[i];
736	<	if (t == null) {
737	<	if (ex == null)
738	<	ex = new NullPointerException();
739	<	}
740	<	else if (i != 0)
741	<	t.fork();
742	<	else {
743	<	t.quietlyInvoke();
744	<	if (ex == null)
745	<	ex = t.getException();
746	<	}
747	<	}
748	<	for (int i = 1; i <= last; ++i) {
749	<	ForkJoinTask<?> t = tasks[i];
750	<	if (t != null) {
751	<	if (ex != null)
752	<	t.cancel(false);
753	<	else {
754	<	t.quietlyJoin();
755	<	if (ex == null)
756	<	ex = t.getException();
757	<	}
758	<	}
759	<	}
760	<	if (ex != null)
761	<	rethrowException(ex);
811	>	public static boolean inForkJoinPool() {
812	>	return Thread.currentThread() instanceof ForkJoinWorkerThread;
813		}
814
815		/**
816	<	* Forks all tasks in the collection, returning when
817	<	* <tt>isDone</tt> holds for all of them. If any task encounters
818	<	* an exception, others may be cancelled.  This method may be
819	<	* invoked only from within other ForkJoinTask
820	<	* computations. Attempts to invoke in other contexts result in
821	<	* exceptions or errors including ClassCastException.
822	<	* @param tasks the collection of tasks
823	<	* @throws NullPointerException if tasks or any element are null.
824	<	* @throws RuntimeException or Error if any task did so.
816	>	* Tries to unschedule this task for execution. This method will
817	>	* typically succeed if this task is the most recently forked task
818	>	* by the current thread, and has not commenced executing in
819	>	* another thread.  This method may be useful when arranging
820	>	* alternative local processing of tasks that could have been, but
821	>	* were not, stolen.
822	>	*
823	>	* <p>This method may be invoked only from within {@code
824	>	* ForkJoinTask} computations (as may be determined using method
825	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
826	>	* result in exceptions or errors, possibly including {@code
827	>	* ClassCastException}.
828	>	*
829	>	* @return {@code true} if unforked
830		*/
831	<	public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) {
832	<	if (!(tasks instanceof List)) {
833	<	invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()]));
778	<	return;
779	<	}
780	<	List<? extends ForkJoinTask<?>> ts =
781	<	(List<? extends ForkJoinTask<?>>)tasks;
782	<	Throwable ex = null;
783	<	int last = ts.size() - 1;
784	<	for (int i = last; i >= 0; --i) {
785	<	ForkJoinTask<?> t = ts.get(i);
786	<	if (t == null) {
787	<	if (ex == null)
788	<	ex = new NullPointerException();
789	<	}
790	<	else if (i != 0)
791	<	t.fork();
792	<	else {
793	<	t.quietlyInvoke();
794	<	if (ex == null)
795	<	ex = t.getException();
796	<	}
797	<	}
798	<	for (int i = 1; i <= last; ++i) {
799	<	ForkJoinTask<?> t = ts.get(i);
800	<	if (t != null) {
801	<	if (ex != null)
802	<	t.cancel(false);
803	<	else {
804	<	t.quietlyJoin();
805	<	if (ex == null)
806	<	ex = t.getException();
807	<	}
808	<	}
809	<	}
810	<	if (ex != null)
811	<	rethrowException(ex);
831	>	public boolean tryUnfork() {
832	>	return ((ForkJoinWorkerThread) Thread.currentThread())
833	>	.unpushTask(this);
834		}
835
836		/**
837	<	* Possibly executes tasks until the pool hosting the current task
838	<	* {@link ForkJoinPool#isQuiescent}. This method may be of use in
839	<	* designs in which many tasks are forked, but none are explicitly
840	<	* joined, instead executing them until all are processed.
837	>	* Returns an estimate of the number of tasks that have been
838	>	* forked by the current worker thread but not yet executed. This
839	>	* value may be useful for heuristic decisions about whether to
840	>	* fork other tasks.
841	>	*
842	>	* <p>This method may be invoked only from within {@code
843	>	* ForkJoinTask} computations (as may be determined using method
844	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
845	>	* result in exceptions or errors, possibly including {@code
846	>	* ClassCastException}.
847	>	*
848	>	* @return the number of tasks
849		*/
850	<	public static void helpQuiesce() {
851	<	((ForkJoinWorkerThread)(Thread.currentThread())).
852	<	helpQuiescePool();
850	>	public static int getQueuedTaskCount() {
851	>	return ((ForkJoinWorkerThread) Thread.currentThread())
852	>	.getQueueSize();
853		}
854
855		/**
856	<	* Returns a estimate of how many more locally queued tasks are
856	>	* Returns an estimate of how many more locally queued tasks are
857		* held by the current worker thread than there are other worker
858	<	* threads that might want to steal them.  This value may be
859	<	* useful for heuristic decisions about whether to fork other
860	<	* tasks. In many usages of ForkJoinTasks, at steady state, each
861	<	* worker should aim to maintain a small constant surplus (for
862	<	* example, 3) of tasks, and to process computations locally if
863	<	* this threshold is exceeded.
858	>	* threads that might steal them.  This value may be useful for
859	>	* heuristic decisions about whether to fork other tasks. In many
860	>	* usages of ForkJoinTasks, at steady state, each worker should
861	>	* aim to maintain a small constant surplus (for example, 3) of
862	>	* tasks, and to process computations locally if this threshold is
863	>	* exceeded.
864	>	*
865	>	* <p>This method may be invoked only from within {@code
866	>	* ForkJoinTask} computations (as may be determined using method
867	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
868	>	* result in exceptions or errors, possibly including {@code
869	>	* ClassCastException}.
870	>	*
871		* @return the surplus number of tasks, which may be negative
872		*/
873	<	public static int surplus() {
874	<	return ((ForkJoinWorkerThread)(Thread.currentThread()))
873	>	public static int getSurplusQueuedTaskCount() {
874	>	return ((ForkJoinWorkerThread) Thread.currentThread())
875		.getEstimatedSurplusTaskCount();
876		}
877
878	<	// Extension kit
878	>	// Extension methods
879
880		/**
881	<	* Returns the result that would be returned by <tt>join</tt>, or
882	<	* null if this task is not known to have been completed.  This
883	<	* method is designed to aid debugging, as well as to support
884	<	* extensions. Its use in any other context is discouraged.
881	>	* Returns the result that would be returned by {@link #join}, even
882	>	* if this task completed abnormally, or {@code null} if this task
883	>	* is not known to have been completed.  This method is designed
884	>	* to aid debugging, as well as to support extensions. Its use in
885	>	* any other context is discouraged.
886		*
887	<	* @return the result, or null if not completed.
887	>	* @return the result, or {@code null} if not completed
888		*/
889		public abstract V getRawResult();
890
#	Line 865 | Line 903 | public abstract class ForkJoinTask<V> im
903		* called otherwise. The return value controls whether this task
904		* is considered to be done normally. It may return false in
905		* asynchronous actions that require explicit invocations of
906	<	* <tt>complete</tt> to become joinable. It may throw exceptions
907	<	* to indicate abnormal exit.
908	<	* @return true if completed normally
909	<	* @throws Error or RuntimeException if encountered during computation
906	>	* {@link #complete} to become joinable. It may also throw an
907	>	* (unchecked) exception to indicate abnormal exit.
908	>	*
909	>	* @return {@code true} if completed normally
910		*/
911		protected abstract boolean exec();
912
913	+	/**
914	+	* Returns, but does not unschedule or execute, a task queued by
915	+	* the current thread but not yet executed, if one is immediately
916	+	* available. There is no guarantee that this task will actually
917	+	* be polled or executed next. Conversely, this method may return
918	+	* null even if a task exists but cannot be accessed without
919	+	* contention with other threads.  This method is designed
920	+	* primarily to support extensions, and is unlikely to be useful
921	+	* otherwise.
922	+	*
923	+	* <p>This method may be invoked only from within {@code
924	+	* ForkJoinTask} computations (as may be determined using method
925	+	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
926	+	* result in exceptions or errors, possibly including {@code
927	+	* ClassCastException}.
928	+	*
929	+	* @return the next task, or {@code null} if none are available
930	+	*/
931	+	protected static ForkJoinTask<?> peekNextLocalTask() {
932	+	return ((ForkJoinWorkerThread) Thread.currentThread())
933	+	.peekTask();
934	+	}
935	+
936	+	/**
937	+	* Unschedules and returns, without executing, the next task
938	+	* queued by the current thread but not yet executed.  This method
939	+	* is designed primarily to support extensions, and is unlikely to
940	+	* be useful otherwise.
941	+	*
942	+	* <p>This method may be invoked only from within {@code
943	+	* ForkJoinTask} computations (as may be determined using method
944	+	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
945	+	* result in exceptions or errors, possibly including {@code
946	+	* ClassCastException}.
947	+	*
948	+	* @return the next task, or {@code null} if none are available
949	+	*/
950	+	protected static ForkJoinTask<?> pollNextLocalTask() {
951	+	return ((ForkJoinWorkerThread) Thread.currentThread())
952	+	.pollLocalTask();
953	+	}
954	+
955	+	/**
956	+	* Unschedules and returns, without executing, the next task
957	+	* queued by the current thread but not yet executed, if one is
958	+	* available, or if not available, a task that was forked by some
959	+	* other thread, if available. Availability may be transient, so a
960	+	* {@code null} result does not necessarily imply quiescence
961	+	* of the pool this task is operating in.  This method is designed
962	+	* primarily to support extensions, and is unlikely to be useful
963	+	* otherwise.
964	+	*
965	+	* <p>This method may be invoked only from within {@code
966	+	* ForkJoinTask} computations (as may be determined using method
967	+	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
968	+	* result in exceptions or errors, possibly including {@code
969	+	* ClassCastException}.
970	+	*
971	+	* @return a task, or {@code null} if none are available
972	+	*/
973	+	protected static ForkJoinTask<?> pollTask() {
974	+	return ((ForkJoinWorkerThread) Thread.currentThread())
975	+	.pollTask();
976	+	}
977	+
978	+	/**
979	+	* Adaptor for Runnables. This implements RunnableFuture
980	+	* to be compliant with AbstractExecutorService constraints
981	+	* when used in ForkJoinPool.
982	+	*/
983	+	static final class AdaptedRunnable<T> extends ForkJoinTask<T>
984	+	implements RunnableFuture<T> {
985	+	final Runnable runnable;
986	+	final T resultOnCompletion;
987	+	T result;
988	+	AdaptedRunnable(Runnable runnable, T result) {
989	+	if (runnable == null) throw new NullPointerException();
990	+	this.runnable = runnable;
991	+	this.resultOnCompletion = result;
992	+	}
993	+	public T getRawResult() { return result; }
994	+	public void setRawResult(T v) { result = v; }
995	+	public boolean exec() {
996	+	runnable.run();
997	+	result = resultOnCompletion;
998	+	return true;
999	+	}
1000	+	public void run() { invoke(); }
1001	+	private static final long serialVersionUID = 5232453952276885070L;
1002	+	}
1003	+
1004	+	/**
1005	+	* Adaptor for Callables
1006	+	*/
1007	+	static final class AdaptedCallable<T> extends ForkJoinTask<T>
1008	+	implements RunnableFuture<T> {
1009	+	final Callable<? extends T> callable;
1010	+	T result;
1011	+	AdaptedCallable(Callable<? extends T> callable) {
1012	+	if (callable == null) throw new NullPointerException();
1013	+	this.callable = callable;
1014	+	}
1015	+	public T getRawResult() { return result; }
1016	+	public void setRawResult(T v) { result = v; }
1017	+	public boolean exec() {
1018	+	try {
1019	+	result = callable.call();
1020	+	return true;
1021	+	} catch (Error err) {
1022	+	throw err;
1023	+	} catch (RuntimeException rex) {
1024	+	throw rex;
1025	+	} catch (Exception ex) {
1026	+	throw new RuntimeException(ex);
1027	+	}
1028	+	}
1029	+	public void run() { invoke(); }
1030	+	private static final long serialVersionUID = 2838392045355241008L;
1031	+	}
1032	+
1033	+	/**
1034	+	* Returns a new {@code ForkJoinTask} that performs the {@code run}
1035	+	* method of the given {@code Runnable} as its action, and returns
1036	+	* a null result upon {@link #join}.
1037	+	*
1038	+	* @param runnable the runnable action
1039	+	* @return the task
1040	+	*/
1041	+	public static ForkJoinTask<?> adapt(Runnable runnable) {
1042	+	return new AdaptedRunnable<Void>(runnable, null);
1043	+	}
1044	+
1045	+	/**
1046	+	* Returns a new {@code ForkJoinTask} that performs the {@code run}
1047	+	* method of the given {@code Runnable} as its action, and returns
1048	+	* the given result upon {@link #join}.
1049	+	*
1050	+	* @param runnable the runnable action
1051	+	* @param result the result upon completion
1052	+	* @return the task
1053	+	*/
1054	+	public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) {
1055	+	return new AdaptedRunnable<T>(runnable, result);
1056	+	}
1057	+
1058	+	/**
1059	+	* Returns a new {@code ForkJoinTask} that performs the {@code call}
1060	+	* method of the given {@code Callable} as its action, and returns
1061	+	* its result upon {@link #join}, translating any checked exceptions
1062	+	* encountered into {@code RuntimeException}.
1063	+	*
1064	+	* @param callable the callable action
1065	+	* @return the task
1066	+	*/
1067	+	public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) {
1068	+	return new AdaptedCallable<T>(callable);
1069	+	}
1070	+
1071		// Serialization support
1072
1073		private static final long serialVersionUID = -7721805057305804111L;
1074
1075		/**
1076	<	* Save the state to a stream.
1076	>	* Saves the state to a stream.
1077		*
1078		* @serialData the current run status and the exception thrown
1079	<	* during execution, or null if none.
1079	>	* during execution, or {@code null} if none
1080		* @param s the stream
1081		*/
1082		private void writeObject(java.io.ObjectOutputStream s)
#	Line 890 | Line 1086 | public abstract class ForkJoinTask<V> im
1086		}
1087
1088		/**
1089	<	* Reconstitute the instance from a stream.
1089	>	* Reconstitutes the instance from a stream.
1090	>	*
1091		* @param s the stream
1092		*/
1093		private void readObject(java.io.ObjectInputStream s)
1094		throws java.io.IOException, ClassNotFoundException {
1095		s.defaultReadObject();
899	–	//        status &= ~INTERNAL_SIGNAL_MASK; //  todo: define policy
1096		Object ex = s.readObject();
1097		if (ex != null)
1098	<	setDoneExceptionally((Throwable)ex);
1098	>	setExceptionalCompletion((Throwable) ex);
1099		}
1100
1101	<	// Temporary Unsafe mechanics for preliminary release
1101	>	// Unsafe mechanics
1102
1103	<	static final Unsafe _unsafe;
1104	<	static final long statusOffset;
1103	>	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1104	>	private static final long statusOffset =
1105	>	objectFieldOffset("status", ForkJoinTask.class);
1106
1107	<	static {
1107	>	private static long objectFieldOffset(String field, Class<?> klazz) {
1108		try {
1109	<	if (ForkJoinTask.class.getClassLoader() != null) {
1110	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1111	<	f.setAccessible(true);
1112	<	_unsafe = (Unsafe)f.get(null);
1113	<	}
1114	<	else
1115	<	_unsafe = Unsafe.getUnsafe();
919	<	statusOffset = _unsafe.objectFieldOffset
920	<	(ForkJoinTask.class.getDeclaredField("status"));
921	<	} catch (Exception ex) { throw new Error(ex); }
1109	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
1110	>	} catch (NoSuchFieldException e) {
1111	>	// Convert Exception to corresponding Error
1112	>	NoSuchFieldError error = new NoSuchFieldError(field);
1113	>	error.initCause(e);
1114	>	throw error;
1115	>	}
1116		}
1117
1118	+	/**
1119	+	* Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
1120	+	* Replace with a simple call to Unsafe.getUnsafe when integrating
1121	+	* into a jdk.
1122	+	*
1123	+	* @return a sun.misc.Unsafe
1124	+	*/
1125	+	private static sun.misc.Unsafe getUnsafe() {
1126	+	try {
1127	+	return sun.misc.Unsafe.getUnsafe();
1128	+	} catch (SecurityException se) {
1129	+	try {
1130	+	return java.security.AccessController.doPrivileged
1131	+	(new java.security
1132	+	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1133	+	public sun.misc.Unsafe run() throws Exception {
1134	+	java.lang.reflect.Field f = sun.misc
1135	+	.Unsafe.class.getDeclaredField("theUnsafe");
1136	+	f.setAccessible(true);
1137	+	return (sun.misc.Unsafe) f.get(null);
1138	+	}});
1139	+	} catch (java.security.PrivilegedActionException e) {
1140	+	throw new RuntimeException("Could not initialize intrinsics",
1141	+	e.getCause());
1142	+	}
1143	+	}
1144	+	}
1145		}

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