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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 1.49 by dl, Wed Jul 7 19:52:31 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	+	/*
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	<	* Status field holding all run status. We pack this into a single
152	<	* int both to minimize footprint overhead and to ensure atomicity
153	<	* (updates are via CAS).
154	<	*
155	<	* Status is initially zero, and takes on nonnegative values until
156	<	* completed, upon which status holds COMPLETED. CANCELLED, or
157	<	* EXCEPTIONAL, which use the top 3 bits.  Tasks undergoing
158	<	* blocking waits by other threads have SIGNAL_MASK bits set --
159	<	* bit 15 for external (nonFJ) waits, and the rest a count of
160	<	* waiting FJ threads.  (This representation relies on
161	<	* ForkJoinPool max thread limits). Completion of a stolen task
162	<	* with SIGNAL_MASK bits set awakens waiter via notifyAll. Even
163	<	* though suboptimal for some purposes, we use basic builtin
164	<	* wait/notify to take advantage of "monitor inflation" in JVMs
165	<	* that we would otherwise need to emulate to avoid adding further
166	<	* per-task bookkeeping overhead. Note that bits 16-28 are
167	<	* currently unused. Also value 0x80000000 is available as spare
168	<	* completion value.
169	<	*/
170	<	volatile int status; // accessed directy by pool and workers
115	<
116	<	static final int COMPLETION_MASK      = 0xe0000000;
117	<	static final int NORMAL               = 0xe0000000; // == mask
118	<	static final int CANCELLED            = 0xc0000000;
119	<	static final int EXCEPTIONAL          = 0xa0000000;
120	<	static final int SIGNAL_MASK          = 0x0000ffff;
121	<	static final int INTERNAL_SIGNAL_MASK = 0x00007fff;
122	<	static final int EXTERNAL_SIGNAL      = 0x00008000; // top bit of low word
151	>	* Run control status bits packed into a single int to minimize
152	>	* footprint and to ensure atomicity (via CAS).  Status is
153	>	* initially zero, and takes on nonnegative values until
154	>	* completed, upon which status holds value COMPLETED. CANCELLED,
155	>	* or EXCEPTIONAL. Tasks undergoing blocking waits by other
156	>	* threads have the SIGNAL bit set.  Completion of a stolen task
157	>	* with SIGNAL set awakens any waiters via notifyAll. Even though
158	>	* suboptimal for some purposes, we use basic builtin wait/notify
159	>	* to take advantage of "monitor inflation" in JVMs that we would
160	>	* otherwise need to emulate to avoid adding further per-task
161	>	* bookkeeping overhead.  We want these monitors to be "fat",
162	>	* i.e., not use biasing or thin-lock techniques, so use some odd
163	>	* coding idioms that tend to avoid them.
164	>	*/
165	>	volatile int status; // accessed directly by pool and workers
166	>
167	>	private static final int NORMAL      = -1;
168	>	private static final int CANCELLED   = -2;
169	>	private static final int EXCEPTIONAL = -3;
170	>	private static final int SIGNAL      =  1;
171
172		/**
173		* Table of exceptions thrown by tasks, to enable reporting by
174		* callers. Because exceptions are rare, we don't directly keep
175	<	* them with task objects, but instead us a weak ref table.  Note
175	>	* them with task objects, but instead use a weak ref table.  Note
176		* that cancellation exceptions don't appear in the table, but are
177		* instead recorded as status values.
178	<	* Todo: Use ConcurrentReferenceHashMap
178	>	* TODO: Use ConcurrentReferenceHashMap
179		*/
180		static final Map<ForkJoinTask<?>, Throwable> exceptionMap =
181		Collections.synchronizedMap
182		(new WeakHashMap<ForkJoinTask<?>, Throwable>());
183
184	<	// 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	<	}
184	>	// Maintaining completion status
185
186		/**
187	<	* Workaround for not being able to rethrow unchecked exceptions.
188	<	*/
189	<	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.
187	>	* Marks completion and wakes up threads waiting to join this task,
188	>	* also clearing signal request bits.
189	>	*
190		* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
191	+	* @return status on exit
192		*/
193	<	final void setCompletion(int completion) {
175	<	ForkJoinPool pool = getWorkerPool();
176	<	if (pool != null) {
177	<	int s; // Clear signal bits while setting completion status
178	<	do;while ((s = status) >= 0 && !casStatus(s, completion));
179	<
180	<	if ((s & SIGNAL_MASK) != 0) {
181	<	if ((s &= INTERNAL_SIGNAL_MASK) != 0)
182	<	pool.updateRunningCount(s);
183	<	synchronized(this) { notifyAll(); }
184	<	}
185	<	}
186	<	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) {
193	>	private int setCompletion(int completion) {
194		int s;
195	<	do;while ((s = status) >= 0 &&
196	<	!casStatus(s, (s & SIGNAL_MASK) | completion));
197	<	synchronized(this) { notifyAll(); }
198	<	}
199	<
200	<	/**
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);
209	<	}
210	<
211	<	// internal waiting and notification
212	<
213	<	/**
214	<	* Performs the actual monitor wait for awaitDone
215	<	*/
216	<	private void doAwaitDone() {
217	<	// Minimize lock bias and in/de-flation effects by maximizing
218	<	// chances of waiting inside sync
219	<	try {
220	<	while (status >= 0)
221	<	synchronized(this) { if (status >= 0) wait(); }
222	<	} catch (InterruptedException ie) {
223	<	onInterruptedWait();
195	>	while ((s = status) >= 0) {
196	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) {
197	>	if (s == SIGNAL)
198	>	synchronized (this) { notifyAll(); }
199	>	return completion;
200	>	}
201		}
202	+	return s;
203		}
204
205		/**
206	<	* Performs the actual monitor wait for awaitDone
206	>	* Record exception and set exceptional completion
207	>	* @return status on exit
208		*/
209	<	private void doAwaitDone(long startTime, long nanos) {
210	<	synchronized(this) {
211	<	try {
233	<	while (status >= 0) {
234	<	long nt = nanos - System.nanoTime() - startTime;
235	<	if (nt <= 0)
236	<	break;
237	<	wait(nt / 1000000, (int)(nt % 1000000));
238	<	}
239	<	} catch (InterruptedException ie) {
240	<	onInterruptedWait();
241	<	}
242	<	}
209	>	private int setExceptionalCompletion(Throwable rex) {
210	>	exceptionMap.put(this, rex);
211	>	return setCompletion(EXCEPTIONAL);
212		}
213
245	–	// Awaiting completion
246	–
214		/**
215	<	* Sets status to indicate there is joiner, then waits for join,
249	<	* surrounded with pool notifications.
250	<	* @return status upon exit
215	>	* Blocks a worker thread until completion. Called only by pool.
216		*/
217	<	final int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) {
253	<	ForkJoinPool pool = w == null? null : w.pool;
217	>	final int internalAwaitDone() {
218		int s;
219		while ((s = status) >= 0) {
220	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
221	<	if (pool == null || !pool.preJoin(this, maintainParallelism))
222	<	doAwaitDone();
223	<	if (((s = status) & INTERNAL_SIGNAL_MASK) != 0)
224	<	adjustPoolCountsOnUnblock(pool);
225	<	break;
220	>	synchronized(this) {
221	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, SIGNAL)) {
222	>	do {
223	>	try {
224	>	wait();
225	>	} catch (InterruptedException ie) {
226	>	cancelIfTerminating();
227	>	}
228	>	} while ((s = status) >= 0);
229	>	break;
230	>	}
231		}
232		}
233		return s;
234		}
235
236		/**
237	<	* Timed version of awaitDone
238	<	* @return status upon exit
237	>	* Blocks a non-worker-thread until completion.
238	>	* @return status on exit
239		*/
240	<	final int awaitDone(ForkJoinWorkerThread w, long nanos) {
272	<	ForkJoinPool pool = w == null? null : w.pool;
240	>	private int externalAwaitDone() {
241		int s;
242		while ((s = status) >= 0) {
243	<	if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) {
244	<	long startTime = System.nanoTime();
245	<	if (pool == null || !pool.preJoin(this, false))
246	<	doAwaitDone(startTime, nanos);
247	<	if ((s = status) >= 0) {
248	<	adjustPoolCountsOnCancelledWait(pool);
249	<	s = status;
243	>	synchronized(this) {
244	>	if (UNSAFE.compareAndSwapInt(this, statusOffset, s, SIGNAL)){
245	>	boolean interrupted = false;
246	>	do {
247	>	try {
248	>	wait();
249	>	} catch (InterruptedException ie) {
250	>	interrupted = true;
251	>	}
252	>	} while ((s = status) >= 0);
253	>	if (interrupted)
254	>	Thread.currentThread().interrupt();
255	>	break;
256		}
283	–	if (s < 0 && (s & INTERNAL_SIGNAL_MASK) != 0)
284	–	adjustPoolCountsOnUnblock(pool);
285	–	break;
257		}
258		}
259		return s;
260		}
261
262		/**
263	<	* Notify pool that thread is unblocked. Called by signalled
264	<	* threads when woken by non-FJ threads (which is atypical).
263	>	* Unless done, calls exec and records status if completed, but
264	>	* doesn't wait for completion otherwise. Primary execution method
265	>	* for ForkJoinWorkerThread.
266		*/
267	<	private void adjustPoolCountsOnUnblock(ForkJoinPool pool) {
268	<	int s;
269	<	do;while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK));
270	<	if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0)
271	<	pool.updateRunningCount(s);
267	>	final void tryExec() {
268	>	try {
269	>	if (status < 0 || !exec())
270	>	return;
271	>	} catch (Throwable rex) {
272	>	setExceptionalCompletion(rex);
273	>	return;
274	>	}
275	>	setCompletion(NORMAL); // must be outside try block
276		}
277
278		/**
279	<	* Notify pool to adjust counts on cancelled or timed out wait
279	>	* If not done and this task is next in worker queue, runs it,
280	>	* else waits for it.
281	>	* @return status on exit
282		*/
283	<	private void adjustPoolCountsOnCancelledWait(ForkJoinPool pool) {
284	<	if (pool != null) {
285	<	int s;
286	<	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() {
283	>	private int doJoin() {
284	>	int stat;
285	>	if ((stat = status) < 0)
286	>	return stat;
287		Thread t = Thread.currentThread();
288	+	ForkJoinWorkerThread w;
289		if (t instanceof ForkJoinWorkerThread) {
290	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)t;
291	<	if (w.isTerminating())
292	<	cancelIgnoreExceptions();
293	<	}
294	<	else { // re-interrupt
295	<	try {
296	<	t.interrupt();
297	<	} catch (SecurityException ignore) {
290	>	if ((w = (ForkJoinWorkerThread) t).unpushTask(this)) {
291	>	boolean completed;
292	>	try {
293	>	completed = exec();
294	>	} catch (Throwable rex) {
295	>	return setExceptionalCompletion(rex);
296	>	}
297	>	if (completed)
298	>	return setCompletion(NORMAL);
299		}
300	+	w.joinTask(this);
301	+	return status;
302		}
303	<	}
331	<
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	<
392	<	/**
393	<	* Calls exec, recording completion, and rethrowing exception if
394	<	* encountered. Caller should normally check status before calling
395	<	* @return true if completed normally
396	<	*/
397	<	private boolean tryExec() {
398	<	try { // try block must contain only call to exec
399	<	if (!exec())
400	<	return false;
401	<	} catch (Throwable rex) {
402	<	setDoneExceptionally(rex);
403	<	rethrowException(rex);
404	<	return false; // not reached
405	<	}
406	<	setNormalCompletion();
407	<	return true;
303	>	return externalAwaitDone();
304		}
305
306		/**
307	<	* Main execution method used by worker threads. Invokes
308	<	* base computation unless already complete
307	>	* Unless done, calls exec and records status if completed, or
308	>	* waits for completion otherwise.
309	>	* @return status on exit
310		*/
311	<	final void quietlyExec() {
312	<	if (status >= 0) {
311	>	private int doInvoke() {
312	>	int stat;
313	>	if ((stat = status) >= 0) {
314	>	boolean completed;
315		try {
316	<	if (!exec())
317	<	return;
318	<	} catch(Throwable rex) {
420	<	setDoneExceptionally(rex);
421	<	return;
316	>	completed = exec();
317	>	} catch (Throwable rex) {
318	>	return setExceptionalCompletion(rex);
319		}
320	<	setNormalCompletion();
321	<	}
322	<	}
323	<
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;
320	>	if (completed)
321	>	stat = setCompletion(NORMAL);
322	>	else
323	>	stat = doJoin();
324		}
325	<	setNormalCompletion();
441	<	return true;
325	>	return stat;
326		}
327
328		/**
329	<	* Cancel, ignoring any exceptions it throws
329	>	* Returns result or throws exception associated with given status.
330	>	* @param s the status
331		*/
332	<	final void cancelIgnoreExceptions() {
333	<	try {
334	<	cancel(false);
335	<	} catch(Throwable ignore) {
336	<	}
332	>	private V reportResult(int s) {
333	>	Throwable ex;
334	>	if (s < NORMAL && (ex = getException()) != null)
335	>	UNSAFE.throwException(ex);
336	>	return getRawResult();
337		}
338
339		// public methods
#	Line 456 | Line 341 | public abstract class ForkJoinTask<V> im
341		/**
342		* Arranges to asynchronously execute this task.  While it is not
343		* necessarily enforced, it is a usage error to fork a task more
344	<	* than once unless it has completed and been reinitialized.  This
345	<	* method may be invoked only from within other ForkJoinTask
346	<	* computations. Attempts to invoke in other contexts result in
347	<	* exceptions or errors including ClassCastException.
344	>	* than once unless it has completed and been reinitialized.
345	>	* Subsequent modifications to the state of this task or any data
346	>	* it operates on are not necessarily consistently observable by
347	>	* any thread other than the one executing it unless preceded by a
348	>	* call to {@link #join} or related methods, or a call to {@link
349	>	* #isDone} returning {@code true}.
350	>	*
351	>	* <p>This method may be invoked only from within {@code
352	>	* ForkJoinTask} computations (as may be determined using method
353	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
354	>	* result in exceptions or errors, possibly including {@code
355	>	* ClassCastException}.
356	>	*
357	>	* @return {@code this}, to simplify usage
358		*/
359	<	public final void fork() {
360	<	((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this);
359	>	public final ForkJoinTask<V> fork() {
360	>	((ForkJoinWorkerThread) Thread.currentThread())
361	>	.pushTask(this);
362	>	return this;
363		}
364
365		/**
366	<	* Returns the result of the computation when it is ready.
367	<	* This method differs from <tt>get</tt> in that abnormal
368	<	* completion results in RuntimeExceptions or Errors, not
369	<	* ExecutionExceptions.
366	>	* Returns the result of the computation when it {@link #isDone is done}.
367	>	* This method differs from {@link #get()} in that
368	>	* abnormal completion results in {@code RuntimeException} or
369	>	* {@code Error}, not {@code ExecutionException}.
370		*
371		* @return the computed result
372		*/
373		public final V join() {
374	<	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();
374	>	return reportResult(doJoin());
375		}
376
377		/**
378	<	* Possibly executes other tasks until this task is ready, then
379	<	* returns the result of the computation.  This method may be more
380	<	* efficient than <tt>join</tt>, but is only applicable when there
381	<	* 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).
378	>	* Commences performing this task, awaits its completion if
379	>	* necessary, and return its result, or throws an (unchecked)
380	>	* exception if the underlying computation did so.
381	>	*
382		* @return the computed result
383		*/
384	<	public final V helpJoin() {
385	<	ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread());
510	<	if (status < 0 || !w.unpushTask(this) || !tryExec())
511	<	reportException(w.helpJoinTask(this));
512	<	return getRawResult();
384	>	public final V invoke() {
385	>	return reportResult(doInvoke());
386		}
387
388		/**
389	<	* Performs this task, awaits its completion if necessary, and
390	<	* return its result.
391	<	* @throws Throwable (a RuntimeException, Error, or unchecked
392	<	* exception) if the underlying computation did so.
393	<	* @return the computed result
389	>	* Forks the given tasks, returning when {@code isDone} holds for
390	>	* each task or an (unchecked) exception is encountered, in which
391	>	* case the exception is rethrown.  If either task encounters an
392	>	* exception, the other one may be, but is not guaranteed to be,
393	>	* cancelled.  If both tasks throw an exception, then this method
394	>	* throws one of them.  The individual status of each task may be
395	>	* checked using {@link #getException()} and related methods.
396	>	*
397	>	* <p>This method may be invoked only from within {@code
398	>	* ForkJoinTask} computations (as may be determined using method
399	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
400	>	* result in exceptions or errors, possibly including {@code
401	>	* ClassCastException}.
402	>	*
403	>	* @param t1 the first task
404	>	* @param t2 the second task
405	>	* @throws NullPointerException if any task is null
406		*/
407	<	public final V invoke() {
408	<	if (status >= 0 && tryExec())
409	<	return getRawResult();
410	<	else
526	<	return join();
407	>	public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) {
408	>	t2.fork();
409	>	t1.invoke();
410	>	t2.join();
411		}
412
413		/**
414	<	* Joins this task, without returning its result or throwing an
415	<	* exception. This method may be useful when processing
416	<	* collections of tasks when some have been cancelled or otherwise
417	<	* known to have aborted.
414	>	* Forks the given tasks, returning when {@code isDone} holds for
415	>	* each task or an (unchecked) exception is encountered, in which
416	>	* case the exception is rethrown. If any task encounters an
417	>	* exception, others may be, but are not guaranteed to be,
418	>	* cancelled.  If more than one task encounters an exception, then
419	>	* this method throws any one of these exceptions.  The individual
420	>	* status of each task may be checked using {@link #getException()}
421	>	* and related methods.
422	>	*
423	>	* <p>This method may be invoked only from within {@code
424	>	* ForkJoinTask} computations (as may be determined using method
425	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
426	>	* result in exceptions or errors, possibly including {@code
427	>	* ClassCastException}.
428	>	*
429	>	* @param tasks the tasks
430	>	* @throws NullPointerException if any task is null
431		*/
432	<	public final void quietlyJoin() {
433	<	if (status >= 0) {
434	<	ForkJoinWorkerThread w = getWorker();
435	<	if (w == null || !w.unpushTask(this) || !tryQuietlyInvoke())
436	<	awaitDone(w, true);
432	>	public static void invokeAll(ForkJoinTask<?>... tasks) {
433	>	Throwable ex = null;
434	>	int last = tasks.length - 1;
435	>	for (int i = last; i >= 0; --i) {
436	>	ForkJoinTask<?> t = tasks[i];
437	>	if (t == null) {
438	>	if (ex == null)
439	>	ex = new NullPointerException();
440	>	}
441	>	else if (i != 0)
442	>	t.fork();
443	>	else if (t.doInvoke() < NORMAL && ex == null)
444	>	ex = t.getException();
445	>	}
446	>	for (int i = 1; i <= last; ++i) {
447	>	ForkJoinTask<?> t = tasks[i];
448	>	if (t != null) {
449	>	if (ex != null)
450	>	t.cancel(false);
451	>	else if (t.doJoin() < NORMAL && ex == null)
452	>	ex = t.getException();
453	>	}
454		}
455	+	if (ex != null)
456	+	UNSAFE.throwException(ex);
457		}
458
459		/**
460	<	* Possibly executes other tasks until this task is ready.
460	>	* Forks all tasks in the specified collection, returning when
461	>	* {@code isDone} holds for each task or an (unchecked) exception
462	>	* is encountered.  If any task encounters an exception, others
463	>	* may be, but are not guaranteed to be, cancelled.  If more than
464	>	* one task encounters an exception, then this method throws any
465	>	* one of these exceptions.  The individual status of each task
466	>	* may be checked using {@link #getException()} and related
467	>	* methods.  The behavior of this operation is undefined if the
468	>	* specified collection is modified while the operation is in
469	>	* progress.
470	>	*
471	>	* <p>This method may be invoked only from within {@code
472	>	* ForkJoinTask} computations (as may be determined using method
473	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
474	>	* result in exceptions or errors, possibly including {@code
475	>	* ClassCastException}.
476	>	*
477	>	* @param tasks the collection of tasks
478	>	* @return the tasks argument, to simplify usage
479	>	* @throws NullPointerException if tasks or any element are null
480		*/
481	<	public final void quietlyHelpJoin() {
482	<	if (status >= 0) {
483	<	ForkJoinWorkerThread w =
484	<	(ForkJoinWorkerThread)(Thread.currentThread());
550	<	if (!w.unpushTask(this) || !tryQuietlyInvoke())
551	<	w.helpJoinTask(this);
481	>	public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) {
482	>	if (!(tasks instanceof RandomAccess) || !(tasks instanceof List<?>)) {
483	>	invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()]));
484	>	return tasks;
485		}
486	+	@SuppressWarnings("unchecked")
487	+	List<? extends ForkJoinTask<?>> ts =
488	+	(List<? extends ForkJoinTask<?>>) tasks;
489	+	Throwable ex = null;
490	+	int last = ts.size() - 1;
491	+	for (int i = last; i >= 0; --i) {
492	+	ForkJoinTask<?> t = ts.get(i);
493	+	if (t == null) {
494	+	if (ex == null)
495	+	ex = new NullPointerException();
496	+	}
497	+	else if (i != 0)
498	+	t.fork();
499	+	else if (t.doInvoke() < NORMAL && ex == null)
500	+	ex = t.getException();
501	+	}
502	+	for (int i = 1; i <= last; ++i) {
503	+	ForkJoinTask<?> t = ts.get(i);
504	+	if (t != null) {
505	+	if (ex != null)
506	+	t.cancel(false);
507	+	else if (t.doJoin() < NORMAL && ex == null)
508	+	ex = t.getException();
509	+	}
510	+	}
511	+	if (ex != null)
512	+	UNSAFE.throwException(ex);
513	+	return tasks;
514		}
515
516		/**
517	<	* Performs this task and awaits its completion if necessary,
518	<	* without returning its result or throwing an exception. This
519	<	* method may be useful when processing collections of tasks when
520	<	* some have been cancelled or otherwise known to have aborted.
517	>	* Attempts to cancel execution of this task. This attempt will
518	>	* fail if the task has already completed, has already been
519	>	* cancelled, or could not be cancelled for some other reason. If
520	>	* successful, and this task has not started when cancel is
521	>	* called, execution of this task is suppressed, {@link
522	>	* #isCancelled} will report true, and {@link #join} will result
523	>	* in a {@code CancellationException} being thrown.
524	>	*
525	>	* <p>This method may be overridden in subclasses, but if so, must
526	>	* still ensure that these minimal properties hold. In particular,
527	>	* the {@code cancel} method itself must not throw exceptions.
528	>	*
529	>	* <p>This method is designed to be invoked by <em>other</em>
530	>	* tasks. To terminate the current task, you can just return or
531	>	* throw an unchecked exception from its computation method, or
532	>	* invoke {@link #completeExceptionally}.
533	>	*
534	>	* @param mayInterruptIfRunning this value is ignored in the
535	>	* default implementation because tasks are not
536	>	* cancelled via interruption
537	>	*
538	>	* @return {@code true} if this task is now cancelled
539		*/
540	<	public final void quietlyInvoke() {
541	<	if (status >= 0 && !tryQuietlyInvoke())
542	<	quietlyJoin();
540	>	public boolean cancel(boolean mayInterruptIfRunning) {
541	>	setCompletion(CANCELLED);
542	>	return status == CANCELLED;
543		}
544
545		/**
546	<	* Returns true if the computation performed by this task has
547	<	* completed (or has been cancelled).
569	<	* @return true if this computation has completed
546	>	* Cancels, ignoring any exceptions it throws. Used during worker
547	>	* and pool shutdown.
548		*/
549	<	public final boolean isDone() {
550	<	return status < 0;
549	>	final void cancelIgnoringExceptions() {
550	>	try {
551	>	cancel(false);
552	>	} catch (Throwable ignore) {
553	>	}
554		}
555
556		/**
557	<	* Returns true if this task was cancelled.
577	<	* @return true if this task was cancelled
557	>	* Cancels ignoring exceptions if worker is terminating
558		*/
559	+	private void cancelIfTerminating() {
560	+	Thread t = Thread.currentThread();
561	+	if ((t instanceof ForkJoinWorkerThread) &&
562	+	((ForkJoinWorkerThread) t).isTerminating()) {
563	+	try {
564	+	cancel(false);
565	+	} catch (Throwable ignore) {
566	+	}
567	+	}
568	+	}
569	+
570	+	public final boolean isDone() {
571	+	return status < 0;
572	+	}
573	+
574		public final boolean isCancelled() {
575	<	return (status & COMPLETION_MASK) == CANCELLED;
575	>	return status == CANCELLED;
576		}
577
578		/**
579	<	* Returns true if this task threw an exception or was cancelled
580	<	* @return true if this task threw an exception or was cancelled
579	>	* Returns {@code true} if this task threw an exception or was cancelled.
580	>	*
581	>	* @return {@code true} if this task threw an exception or was cancelled
582		*/
583	<	public final boolean completedAbnormally() {
584	<	return (status & COMPLETION_MASK) < NORMAL;
583	>	public final boolean isCompletedAbnormally() {
584	>	return status < NORMAL;
585		}
586
587		/**
588	<	* Returns the exception thrown by the base computation, or a
589	<	* CancellationException if cancelled, or null if none or if the
590	<	* method has not yet completed.
591	<	* @return the exception, or null if none
588	>	* Returns {@code true} if this task completed without throwing an
589	>	* exception and was not cancelled.
590	>	*
591	>	* @return {@code true} if this task completed without throwing an
592	>	* exception and was not cancelled
593		*/
594	<	public final Throwable getException() {
595	<	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);
594	>	public final boolean isCompletedNormally() {
595	>	return status == NORMAL;
596		}
597
598		/**
599	<	* Asserts that the results of this task's computation will not be
600	<	* used. If a cancellation occurs before this task is processed,
601	<	* 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.
599	>	* Returns the exception thrown by the base computation, or a
600	>	* {@code CancellationException} if cancelled, or {@code null} if
601	>	* none or if the method has not yet completed.
602		*
603	<	* @return true if this task is now cancelled
603	>	* @return the exception, or {@code null} if none
604		*/
605	<	public boolean cancel(boolean mayInterruptIfRunning) {
606	<	setCompletion(CANCELLED);
607	<	return (status & COMPLETION_MASK) == CANCELLED;
605	>	public final Throwable getException() {
606	>	int s = status;
607	>	return ((s >= NORMAL)    ? null :
608	>	(s == CANCELLED) ? new CancellationException() :
609	>	exceptionMap.get(this));
610		}
611
612		/**
613		* Completes this task abnormally, and if not already aborted or
614		* cancelled, causes it to throw the given exception upon
615	<	* <tt>join</tt> and related operations. This method may be used
615	>	* {@code join} and related operations. This method may be used
616		* to induce exceptions in asynchronous tasks, or to force
617	<	* completion of tasks that would not otherwise complete.  This
618	<	* method is overridable, but overridden versions must invoke
619	<	* <tt>super</tt> implementation to maintain guarantees.
620	<	* @param ex the exception to throw. If this exception is
621	<	* not a RuntimeException or Error, the actual exception thrown
622	<	* will be a RuntimeException with cause ex.
617	>	* completion of tasks that would not otherwise complete.  Its use
618	>	* in other situations is discouraged.  This method is
619	>	* overridable, but overridden versions must invoke {@code super}
620	>	* implementation to maintain guarantees.
621	>	*
622	>	* @param ex the exception to throw. If this exception is not a
623	>	* {@code RuntimeException} or {@code Error}, the actual exception
624	>	* thrown will be a {@code RuntimeException} with cause {@code ex}.
625		*/
626		public void completeExceptionally(Throwable ex) {
627	<	setDoneExceptionally((ex instanceof RuntimeException) ||
628	<	(ex instanceof Error)? ex :
629	<	new RuntimeException(ex));
627	>	setExceptionalCompletion((ex instanceof RuntimeException) ||
628	>	(ex instanceof Error) ? ex :
629	>	new RuntimeException(ex));
630		}
631
632		/**
633		* Completes this task, and if not already aborted or cancelled,
634	<	* returning a <tt>null</tt> result upon <tt>join</tt> and related
634	>	* returning a {@code null} result upon {@code join} and related
635		* operations. This method may be used to provide results for
636		* asynchronous tasks, or to provide alternative handling for
637	<	* tasks that would not otherwise complete normally.
637	>	* tasks that would not otherwise complete normally. Its use in
638	>	* other situations is discouraged. This method is
639	>	* overridable, but overridden versions must invoke {@code super}
640	>	* implementation to maintain guarantees.
641		*
642	<	* @param value the result value for this task.
642	>	* @param value the result value for this task
643		*/
644		public void complete(V value) {
645		try {
646		setRawResult(value);
647	<	} catch(Throwable rex) {
648	<	setDoneExceptionally(rex);
647	>	} catch (Throwable rex) {
648	>	setExceptionalCompletion(rex);
649		return;
650		}
651	<	setNormalCompletion();
651	>	setCompletion(NORMAL);
652	>	}
653	>
654	>	public final V get() throws InterruptedException, ExecutionException {
655	>	int s = doJoin();
656	>	if (Thread.interrupted())
657	>	throw new InterruptedException();
658	>	if (s < NORMAL) {
659	>	Throwable ex;
660	>	if (s == CANCELLED)
661	>	throw new CancellationException();
662	>	if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
663	>	throw new ExecutionException(ex);
664	>	}
665	>	return getRawResult();
666	>	}
667	>
668	>	public final V get(long timeout, TimeUnit unit)
669	>	throws InterruptedException, ExecutionException, TimeoutException {
670	>	Thread t = Thread.currentThread();
671	>	ForkJoinPool pool;
672	>	if (t instanceof ForkJoinWorkerThread) {
673	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) t;
674	>	if (status >= 0 && w.unpushTask(this))
675	>	tryExec();
676	>	pool = w.pool;
677	>	}
678	>	else
679	>	pool = null;
680	>	/*
681	>	* Timed wait loop intermixes cases for fj (pool != null) and
682	>	* non FJ threads. For FJ, decrement pool count but don't try
683	>	* for replacement; increment count on completion. For non-FJ,
684	>	* deal with interrupts. This is messy, but a little less so
685	>	* than is splitting the FJ and nonFJ cases.
686	>	*/
687	>	boolean interrupted = false;
688	>	boolean dec = false; // true if pool count decremented
689	>	for (;;) {
690	>	if (Thread.interrupted() && pool == null) {
691	>	interrupted = true;
692	>	break;
693	>	}
694	>	int s = status;
695	>	if (s < 0)
696	>	break;
697	>	if (UNSAFE.compareAndSwapInt(this, statusOffset,
698	>	s, s | SIGNAL)) {
699	>	long startTime = System.nanoTime();
700	>	long nanos = unit.toNanos(timeout);
701	>	long nt; // wait time
702	>	while (status >= 0 &&
703	>	(nt = nanos - (System.nanoTime() - startTime)) > 0) {
704	>	if (pool != null && !dec)
705	>	dec = pool.tryDecrementRunningCount();
706	>	else {
707	>	long ms = nt / 1000000;
708	>	int ns = (int) (nt % 1000000);
709	>	try {
710	>	synchronized(this) {
711	>	if (status >= 0)
712	>	wait(ms, ns);
713	>	}
714	>	} catch (InterruptedException ie) {
715	>	if (pool != null)
716	>	cancelIfTerminating();
717	>	else {
718	>	interrupted = true;
719	>	break;
720	>	}
721	>	}
722	>	}
723	>	}
724	>	break;
725	>	}
726	>	}
727	>	if (pool != null && dec)
728	>	pool.incrementRunningCount();
729	>	if (interrupted)
730	>	throw new InterruptedException();
731	>	int es = status;
732	>	if (es != NORMAL) {
733	>	Throwable ex;
734	>	if (es == CANCELLED)
735	>	throw new CancellationException();
736	>	if (es == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null)
737	>	throw new ExecutionException(ex);
738	>	throw new TimeoutException();
739	>	}
740	>	return getRawResult();
741	>	}
742	>
743	>	/**
744	>	* Joins this task, without returning its result or throwing an
745	>	* exception. This method may be useful when processing
746	>	* collections of tasks when some have been cancelled or otherwise
747	>	* known to have aborted.
748	>	*/
749	>	public final void quietlyJoin() {
750	>	doJoin();
751	>	}
752	>
753	>	/**
754	>	* Commences performing this task and awaits its completion if
755	>	* necessary, without returning its result or throwing an
756	>	* exception. This method may be useful when processing
757	>	* collections of tasks when some have been cancelled or otherwise
758	>	* known to have aborted.
759	>	*/
760	>	public final void quietlyInvoke() {
761	>	doInvoke();
762	>	}
763	>
764	>	/**
765	>	* Possibly executes tasks until the pool hosting the current task
766	>	* {@link ForkJoinPool#isQuiescent is quiescent}. This method may
767	>	* be of use in designs in which many tasks are forked, but none
768	>	* are explicitly joined, instead executing them until all are
769	>	* processed.
770	>	*
771	>	* <p>This method may be invoked only from within {@code
772	>	* ForkJoinTask} computations (as may be determined using method
773	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
774	>	* result in exceptions or errors, possibly including {@code
775	>	* ClassCastException}.
776	>	*/
777	>	public static void helpQuiesce() {
778	>	((ForkJoinWorkerThread) Thread.currentThread())
779	>	.helpQuiescePool();
780		}
781
782		/**
783		* Resets the internal bookkeeping state of this task, allowing a
784	<	* subsequent <tt>fork</tt>. This method allows repeated reuse of
784	>	* subsequent {@code fork}. This method allows repeated reuse of
785		* this task, but only if reuse occurs when this task has either
786		* never been forked, or has been forked, then completed and all
787		* outstanding joins of this task have also completed. Effects
788	<	* under any other usage conditions are not guaranteed, and are
789	<	* almost surely wrong. This method may be useful when executing
788	>	* under any other usage conditions are not guaranteed.
789	>	* This method may be useful when executing
790		* pre-constructed trees of subtasks in loops.
791		*/
792		public void reinitialize() {
793	<	if ((status & COMPLETION_MASK) == EXCEPTIONAL)
793	>	if (status == EXCEPTIONAL)
794		exceptionMap.remove(this);
795		status = 0;
796		}
797
798		/**
799	<	* Tries to unschedule this task for execution. This method will
800	<	* typically succeed if this task is the next task that would be
801	<	* executed by the current thread, and will typically fail (return
802	<	* false) otherwise. This method may be useful when arranging
803	<	* 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.
799	>	* Returns the pool hosting the current task execution, or null
800	>	* if this task is executing outside of any ForkJoinPool.
801	>	*
802	>	* @see #inForkJoinPool
803	>	* @return the pool, or {@code null} if none
804		*/
805	<	public static void invokeAll(ForkJoinTask<?>t1, ForkJoinTask<?> t2) {
806	<	t2.fork();
807	<	t1.invoke();
808	<	t2.join();
805	>	public static ForkJoinPool getPool() {
806	>	Thread t = Thread.currentThread();
807	>	return (t instanceof ForkJoinWorkerThread) ?
808	>	((ForkJoinWorkerThread) t).pool : null;
809		}
810
811		/**
812	<	* Forks the given tasks, returning when <tt>isDone</tt> holds for
813	<	* all of them. If any task encounters an exception, others may be
814	<	* cancelled.  This method may be invoked only from within other
815	<	* ForkJoinTask computations. Attempts to invoke in other contexts
816	<	* 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.
812	>	* Returns {@code true} if the current thread is executing as a
813	>	* ForkJoinPool computation.
814	>	*
815	>	* @return {@code true} if the current thread is executing as a
816	>	* ForkJoinPool computation, or false otherwise
817		*/
818	<	public static void invokeAll(ForkJoinTask<?>... tasks) {
819	<	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);
818	>	public static boolean inForkJoinPool() {
819	>	return Thread.currentThread() instanceof ForkJoinWorkerThread;
820		}
821
822		/**
823	<	* Forks all tasks in the collection, returning when
824	<	* <tt>isDone</tt> holds for all of them. If any task encounters
825	<	* an exception, others may be cancelled.  This method may be
826	<	* invoked only from within other ForkJoinTask
827	<	* computations. Attempts to invoke in other contexts result in
828	<	* exceptions or errors including ClassCastException.
829	<	* @param tasks the collection of tasks
830	<	* @throws NullPointerException if tasks or any element are null.
831	<	* @throws RuntimeException or Error if any task did so.
823	>	* Tries to unschedule this task for execution. This method will
824	>	* typically succeed if this task is the most recently forked task
825	>	* by the current thread, and has not commenced executing in
826	>	* another thread.  This method may be useful when arranging
827	>	* alternative local processing of tasks that could have been, but
828	>	* were not, stolen.
829	>	*
830	>	* <p>This method may be invoked only from within {@code
831	>	* ForkJoinTask} computations (as may be determined using method
832	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
833	>	* result in exceptions or errors, possibly including {@code
834	>	* ClassCastException}.
835	>	*
836	>	* @return {@code true} if unforked
837		*/
838	<	public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) {
839	<	if (!(tasks instanceof List)) {
840	<	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);
838	>	public boolean tryUnfork() {
839	>	return ((ForkJoinWorkerThread) Thread.currentThread())
840	>	.unpushTask(this);
841		}
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.
844	>	* Returns an estimate of the number of tasks that have been
845	>	* forked by the current worker thread but not yet executed. This
846	>	* value may be useful for heuristic decisions about whether to
847	>	* fork other tasks.
848	>	*
849	>	* <p>This method may be invoked only from within {@code
850	>	* ForkJoinTask} computations (as may be determined using method
851	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
852	>	* result in exceptions or errors, possibly including {@code
853	>	* ClassCastException}.
854	>	*
855	>	* @return the number of tasks
856		*/
857	<	public static void helpQuiesce() {
858	<	((ForkJoinWorkerThread)(Thread.currentThread())).
859	<	helpQuiescePool();
857	>	public static int getQueuedTaskCount() {
858	>	return ((ForkJoinWorkerThread) Thread.currentThread())
859	>	.getQueueSize();
860		}
861
862		/**
863	<	* Returns a estimate of how many more locally queued tasks are
863	>	* Returns an estimate of how many more locally queued tasks are
864		* held by the current worker thread than there are other worker
865	<	* threads that might want to steal them.  This value may be
866	<	* useful for heuristic decisions about whether to fork other
867	<	* tasks. In many usages of ForkJoinTasks, at steady state, each
868	<	* worker should aim to maintain a small constant surplus (for
869	<	* example, 3) of tasks, and to process computations locally if
870	<	* this threshold is exceeded.
865	>	* threads that might steal them.  This value may be useful for
866	>	* heuristic decisions about whether to fork other tasks. In many
867	>	* usages of ForkJoinTasks, at steady state, each worker should
868	>	* aim to maintain a small constant surplus (for example, 3) of
869	>	* tasks, and to process computations locally if this threshold is
870	>	* exceeded.
871	>	*
872	>	* <p>This method may be invoked only from within {@code
873	>	* ForkJoinTask} computations (as may be determined using method
874	>	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
875	>	* result in exceptions or errors, possibly including {@code
876	>	* ClassCastException}.
877	>	*
878		* @return the surplus number of tasks, which may be negative
879		*/
880	<	public static int surplus() {
881	<	return ((ForkJoinWorkerThread)(Thread.currentThread()))
880	>	public static int getSurplusQueuedTaskCount() {
881	>	return ((ForkJoinWorkerThread) Thread.currentThread())
882		.getEstimatedSurplusTaskCount();
883		}
884
885	<	// Extension kit
885	>	// Extension methods
886
887		/**
888	<	* Returns the result that would be returned by <tt>join</tt>, or
889	<	* null if this task is not known to have been completed.  This
890	<	* method is designed to aid debugging, as well as to support
891	<	* extensions. Its use in any other context is discouraged.
888	>	* Returns the result that would be returned by {@link #join}, even
889	>	* if this task completed abnormally, or {@code null} if this task
890	>	* is not known to have been completed.  This method is designed
891	>	* to aid debugging, as well as to support extensions. Its use in
892	>	* any other context is discouraged.
893		*
894	<	* @return the result, or null if not completed.
894	>	* @return the result, or {@code null} if not completed
895		*/
896		public abstract V getRawResult();
897
#	Line 865 | Line 910 | public abstract class ForkJoinTask<V> im
910		* called otherwise. The return value controls whether this task
911		* is considered to be done normally. It may return false in
912		* asynchronous actions that require explicit invocations of
913	<	* <tt>complete</tt> to become joinable. It may throw exceptions
914	<	* to indicate abnormal exit.
915	<	* @return true if completed normally
916	<	* @throws Error or RuntimeException if encountered during computation
913	>	* {@link #complete} to become joinable. It may also throw an
914	>	* (unchecked) exception to indicate abnormal exit.
915	>	*
916	>	* @return {@code true} if completed normally
917		*/
918		protected abstract boolean exec();
919
920	+	/**
921	+	* Returns, but does not unschedule or execute, a task queued by
922	+	* the current thread but not yet executed, if one is immediately
923	+	* available. There is no guarantee that this task will actually
924	+	* be polled or executed next. Conversely, this method may return
925	+	* null even if a task exists but cannot be accessed without
926	+	* contention with other threads.  This method is designed
927	+	* primarily to support extensions, and is unlikely to be useful
928	+	* otherwise.
929	+	*
930	+	* <p>This method may be invoked only from within {@code
931	+	* ForkJoinTask} computations (as may be determined using method
932	+	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
933	+	* result in exceptions or errors, possibly including {@code
934	+	* ClassCastException}.
935	+	*
936	+	* @return the next task, or {@code null} if none are available
937	+	*/
938	+	protected static ForkJoinTask<?> peekNextLocalTask() {
939	+	return ((ForkJoinWorkerThread) Thread.currentThread())
940	+	.peekTask();
941	+	}
942	+
943	+	/**
944	+	* Unschedules and returns, without executing, the next task
945	+	* queued by the current thread but not yet executed.  This method
946	+	* is designed primarily to support extensions, and is unlikely to
947	+	* be useful otherwise.
948	+	*
949	+	* <p>This method may be invoked only from within {@code
950	+	* ForkJoinTask} computations (as may be determined using method
951	+	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
952	+	* result in exceptions or errors, possibly including {@code
953	+	* ClassCastException}.
954	+	*
955	+	* @return the next task, or {@code null} if none are available
956	+	*/
957	+	protected static ForkJoinTask<?> pollNextLocalTask() {
958	+	return ((ForkJoinWorkerThread) Thread.currentThread())
959	+	.pollLocalTask();
960	+	}
961	+
962	+	/**
963	+	* Unschedules and returns, without executing, the next task
964	+	* queued by the current thread but not yet executed, if one is
965	+	* available, or if not available, a task that was forked by some
966	+	* other thread, if available. Availability may be transient, so a
967	+	* {@code null} result does not necessarily imply quiescence
968	+	* of the pool this task is operating in.  This method is designed
969	+	* primarily to support extensions, and is unlikely to be useful
970	+	* otherwise.
971	+	*
972	+	* <p>This method may be invoked only from within {@code
973	+	* ForkJoinTask} computations (as may be determined using method
974	+	* {@link #inForkJoinPool}).  Attempts to invoke in other contexts
975	+	* result in exceptions or errors, possibly including {@code
976	+	* ClassCastException}.
977	+	*
978	+	* @return a task, or {@code null} if none are available
979	+	*/
980	+	protected static ForkJoinTask<?> pollTask() {
981	+	return ((ForkJoinWorkerThread) Thread.currentThread())
982	+	.pollTask();
983	+	}
984	+
985	+	/**
986	+	* Adaptor for Runnables. This implements RunnableFuture
987	+	* to be compliant with AbstractExecutorService constraints
988	+	* when used in ForkJoinPool.
989	+	*/
990	+	static final class AdaptedRunnable<T> extends ForkJoinTask<T>
991	+	implements RunnableFuture<T> {
992	+	final Runnable runnable;
993	+	final T resultOnCompletion;
994	+	T result;
995	+	AdaptedRunnable(Runnable runnable, T result) {
996	+	if (runnable == null) throw new NullPointerException();
997	+	this.runnable = runnable;
998	+	this.resultOnCompletion = result;
999	+	}
1000	+	public T getRawResult() { return result; }
1001	+	public void setRawResult(T v) { result = v; }
1002	+	public boolean exec() {
1003	+	runnable.run();
1004	+	result = resultOnCompletion;
1005	+	return true;
1006	+	}
1007	+	public void run() { invoke(); }
1008	+	private static final long serialVersionUID = 5232453952276885070L;
1009	+	}
1010	+
1011	+	/**
1012	+	* Adaptor for Callables
1013	+	*/
1014	+	static final class AdaptedCallable<T> extends ForkJoinTask<T>
1015	+	implements RunnableFuture<T> {
1016	+	final Callable<? extends T> callable;
1017	+	T result;
1018	+	AdaptedCallable(Callable<? extends T> callable) {
1019	+	if (callable == null) throw new NullPointerException();
1020	+	this.callable = callable;
1021	+	}
1022	+	public T getRawResult() { return result; }
1023	+	public void setRawResult(T v) { result = v; }
1024	+	public boolean exec() {
1025	+	try {
1026	+	result = callable.call();
1027	+	return true;
1028	+	} catch (Error err) {
1029	+	throw err;
1030	+	} catch (RuntimeException rex) {
1031	+	throw rex;
1032	+	} catch (Exception ex) {
1033	+	throw new RuntimeException(ex);
1034	+	}
1035	+	}
1036	+	public void run() { invoke(); }
1037	+	private static final long serialVersionUID = 2838392045355241008L;
1038	+	}
1039	+
1040	+	/**
1041	+	* Returns a new {@code ForkJoinTask} that performs the {@code run}
1042	+	* method of the given {@code Runnable} as its action, and returns
1043	+	* a null result upon {@link #join}.
1044	+	*
1045	+	* @param runnable the runnable action
1046	+	* @return the task
1047	+	*/
1048	+	public static ForkJoinTask<?> adapt(Runnable runnable) {
1049	+	return new AdaptedRunnable<Void>(runnable, null);
1050	+	}
1051	+
1052	+	/**
1053	+	* Returns a new {@code ForkJoinTask} that performs the {@code run}
1054	+	* method of the given {@code Runnable} as its action, and returns
1055	+	* the given result upon {@link #join}.
1056	+	*
1057	+	* @param runnable the runnable action
1058	+	* @param result the result upon completion
1059	+	* @return the task
1060	+	*/
1061	+	public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) {
1062	+	return new AdaptedRunnable<T>(runnable, result);
1063	+	}
1064	+
1065	+	/**
1066	+	* Returns a new {@code ForkJoinTask} that performs the {@code call}
1067	+	* method of the given {@code Callable} as its action, and returns
1068	+	* its result upon {@link #join}, translating any checked exceptions
1069	+	* encountered into {@code RuntimeException}.
1070	+	*
1071	+	* @param callable the callable action
1072	+	* @return the task
1073	+	*/
1074	+	public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) {
1075	+	return new AdaptedCallable<T>(callable);
1076	+	}
1077	+
1078		// Serialization support
1079
1080		private static final long serialVersionUID = -7721805057305804111L;
1081
1082		/**
1083	<	* Save the state to a stream.
1083	>	* Saves the state to a stream.
1084		*
1085		* @serialData the current run status and the exception thrown
1086	<	* during execution, or null if none.
1086	>	* during execution, or {@code null} if none
1087		* @param s the stream
1088		*/
1089		private void writeObject(java.io.ObjectOutputStream s)
#	Line 890 | Line 1093 | public abstract class ForkJoinTask<V> im
1093		}
1094
1095		/**
1096	<	* Reconstitute the instance from a stream.
1096	>	* Reconstitutes the instance from a stream.
1097	>	*
1098		* @param s the stream
1099		*/
1100		private void readObject(java.io.ObjectInputStream s)
1101		throws java.io.IOException, ClassNotFoundException {
1102		s.defaultReadObject();
899	–	//        status &= ~INTERNAL_SIGNAL_MASK; //  todo: define policy
1103		Object ex = s.readObject();
1104		if (ex != null)
1105	<	setDoneExceptionally((Throwable)ex);
1105	>	setExceptionalCompletion((Throwable) ex);
1106	>	if (status < 0)
1107	>	synchronized (this) { notifyAll(); }
1108		}
1109
1110	<	// Temporary Unsafe mechanics for preliminary release
1110	>	// Unsafe mechanics
1111
1112	<	static final Unsafe _unsafe;
1113	<	static final long statusOffset;
1112	>	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1113	>	private static final long statusOffset =
1114	>	objectFieldOffset("status", ForkJoinTask.class);
1115
1116	<	static {
1116	>	private static long objectFieldOffset(String field, Class<?> klazz) {
1117		try {
1118	<	if (ForkJoinTask.class.getClassLoader() != null) {
1119	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1120	<	f.setAccessible(true);
1121	<	_unsafe = (Unsafe)f.get(null);
1122	<	}
1123	<	else
1124	<	_unsafe = Unsafe.getUnsafe();
919	<	statusOffset = _unsafe.objectFieldOffset
920	<	(ForkJoinTask.class.getDeclaredField("status"));
921	<	} catch (Exception ex) { throw new Error(ex); }
1118	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
1119	>	} catch (NoSuchFieldException e) {
1120	>	// Convert Exception to corresponding Error
1121	>	NoSuchFieldError error = new NoSuchFieldError(field);
1122	>	error.initCause(e);
1123	>	throw error;
1124	>	}
1125		}
1126
1127	+	/**
1128	+	* Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
1129	+	* Replace with a simple call to Unsafe.getUnsafe when integrating
1130	+	* into a jdk.
1131	+	*
1132	+	* @return a sun.misc.Unsafe
1133	+	*/
1134	+	private static sun.misc.Unsafe getUnsafe() {
1135	+	try {
1136	+	return sun.misc.Unsafe.getUnsafe();
1137	+	} catch (SecurityException se) {
1138	+	try {
1139	+	return java.security.AccessController.doPrivileged
1140	+	(new java.security
1141	+	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1142	+	public sun.misc.Unsafe run() throws Exception {
1143	+	java.lang.reflect.Field f = sun.misc
1144	+	.Unsafe.class.getDeclaredField("theUnsafe");
1145	+	f.setAccessible(true);
1146	+	return (sun.misc.Unsafe) f.get(null);
1147	+	}});
1148	+	} catch (java.security.PrivilegedActionException e) {
1149	+	throw new RuntimeException("Could not initialize intrinsics",
1150	+	e.getCause());
1151	+	}
1152	+	}
1153	+	}
1154		}

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