43 |
|
* <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}. |
44 |
|
* The efficiency of {@code ForkJoinTask}s stems from a set of |
45 |
|
* restrictions (that are only partially statically enforceable) |
46 |
< |
* reflecting their intended use as computational tasks calculating |
47 |
< |
* pure functions or operating on purely isolated objects. The |
48 |
< |
* primary coordination mechanisms are {@link #fork}, that arranges |
46 |
> |
* reflecting their main use as computational tasks calculating pure |
47 |
> |
* functions or operating on purely isolated objects. The primary |
48 |
> |
* coordination mechanisms are {@link #fork}, that arranges |
49 |
|
* asynchronous execution, and {@link #join}, that doesn't proceed |
50 |
|
* until the task's result has been computed. Computations should |
51 |
< |
* avoid {@code synchronized} methods or blocks, and should minimize |
52 |
< |
* other blocking synchronization apart from joining other tasks or |
53 |
< |
* using synchronizers such as Phasers that are advertised to |
54 |
< |
* cooperate with fork/join scheduling. Tasks should also not perform |
55 |
< |
* blocking IO, and should ideally access variables that are |
56 |
< |
* completely independent of those accessed by other running |
57 |
< |
* tasks. Minor breaches of these restrictions, for example using |
58 |
< |
* shared output streams, may be tolerable in practice, but frequent |
59 |
< |
* use may result in poor performance, and the potential to |
60 |
< |
* indefinitely stall if the number of threads not waiting for IO or |
61 |
< |
* other external synchronization becomes exhausted. This usage |
62 |
< |
* restriction is in part enforced by not permitting checked |
63 |
< |
* exceptions such as {@code IOExceptions} to be thrown. However, |
64 |
< |
* computations may still encounter unchecked exceptions, that are |
65 |
< |
* rethrown to callers attempting to join them. These exceptions may |
66 |
< |
* additionally include {@link RejectedExecutionException} stemming |
67 |
< |
* from internal resource exhaustion, such as failure to allocate |
68 |
< |
* internal task queues. Rethrown exceptions behave in the same way as |
69 |
< |
* regular exceptions, but, when possible, contain stack traces (as |
70 |
< |
* displayed for example using {@code ex.printStackTrace()}) of both |
71 |
< |
* the thread that initiated the computation as well as the thread |
72 |
< |
* actually encountering the exception; minimally only the latter. |
51 |
> |
* ideally avoid {@code synchronized} methods or blocks, and should |
52 |
> |
* minimize other blocking synchronization apart from joining other |
53 |
> |
* tasks or using synchronizers such as Phasers that are advertised to |
54 |
> |
* cooperate with fork/join scheduling. Subdividable tasks should also |
55 |
> |
* not perform blocking IO, and should ideally access variables that |
56 |
> |
* are completely independent of those accessed by other running |
57 |
> |
* tasks. These guidelines are loosely enforced by not permitting |
58 |
> |
* checked exceptions such as {@code IOExceptions} to be |
59 |
> |
* thrown. However, computations may still encounter unchecked |
60 |
> |
* exceptions, that are rethrown to callers attempting to join |
61 |
> |
* them. These exceptions may additionally include {@link |
62 |
> |
* RejectedExecutionException} stemming from internal resource |
63 |
> |
* exhaustion, such as failure to allocate internal task |
64 |
> |
* queues. Rethrown exceptions behave in the same way as regular |
65 |
> |
* exceptions, but, when possible, contain stack traces (as displayed |
66 |
> |
* for example using {@code ex.printStackTrace()}) of both the thread |
67 |
> |
* that initiated the computation as well as the thread actually |
68 |
> |
* encountering the exception; minimally only the latter. |
69 |
> |
* |
70 |
> |
* <p>It is possible to define and use ForkJoinTasks that may block, |
71 |
> |
* but doing do requires three further considerations: (1) Completion |
72 |
> |
* of few if any <em>other</em> tasks should be dependent on a task |
73 |
> |
* that blocks on external synchronization or IO. Event-style async |
74 |
> |
* tasks that are never joined often fall into this category. (2) To |
75 |
> |
* minimize resource impact, tasks should be small; ideally performing |
76 |
> |
* only the (possibly) blocking action. (3) Unless the {@link |
77 |
> |
* ForkJoinPool.ManagedBlocker} API is used, or the number of possibly |
78 |
> |
* blocked tasks is known to be less than the pool's {@link |
79 |
> |
* ForkJoinPool#getParallelism} level, the pool cannot guarantee that |
80 |
> |
* enough threads will be available to ensure progress or good |
81 |
> |
* performance. |
82 |
|
* |
83 |
|
* <p>The primary method for awaiting completion and extracting |
84 |
|
* results of a task is {@link #join}, but there are several variants: |
94 |
|
* performs the most common form of parallel invocation: forking a set |
95 |
|
* of tasks and joining them all. |
96 |
|
* |
97 |
+ |
* <p>In the most typical usages, a fork-join pair act like a call |
98 |
+ |
* (fork) and return (join) from a parallel recursive function. As is |
99 |
+ |
* the case with other forms of recursive calls, returns (joins) |
100 |
+ |
* should be performed innermost-first. For example, {@code a.fork(); |
101 |
+ |
* b.fork(); b.join(); a.join();} is likely to be substantially more |
102 |
+ |
* efficient than joining {@code a} before {@code b}. |
103 |
+ |
* |
104 |
|
* <p>The execution status of tasks may be queried at several levels |
105 |
|
* of detail: {@link #isDone} is true if a task completed in any way |
106 |
|
* (including the case where a task was cancelled without executing); |
116 |
|
* <p>The ForkJoinTask class is not usually directly subclassed. |
117 |
|
* Instead, you subclass one of the abstract classes that support a |
118 |
|
* particular style of fork/join processing, typically {@link |
119 |
< |
* RecursiveAction} for computations that do not return results, or |
120 |
< |
* {@link RecursiveTask} for those that do. Normally, a concrete |
121 |
< |
* ForkJoinTask subclass declares fields comprising its parameters, |
122 |
< |
* established in a constructor, and then defines a {@code compute} |
123 |
< |
* method that somehow uses the control methods supplied by this base |
124 |
< |
* class. While these methods have {@code public} access (to allow |
125 |
< |
* instances of different task subclasses to call each other's |
126 |
< |
* methods), some of them may only be called from within other |
127 |
< |
* ForkJoinTasks (as may be determined using method {@link |
128 |
< |
* #inForkJoinPool}). Attempts to invoke them in other contexts |
129 |
< |
* result in exceptions or errors, possibly including |
130 |
< |
* {@code ClassCastException}. |
119 |
> |
* RecursiveAction} for most computations that do not return results, |
120 |
> |
* {@link RecursiveTask} for those that do, and {@link |
121 |
> |
* CountedCompleter} for those in which completed actions trigger |
122 |
> |
* other actions. Normally, a concrete ForkJoinTask subclass declares |
123 |
> |
* fields comprising its parameters, established in a constructor, and |
124 |
> |
* then defines a {@code compute} method that somehow uses the control |
125 |
> |
* methods supplied by this base class. While these methods have |
126 |
> |
* {@code public} access (to allow instances of different task |
127 |
> |
* subclasses to call each other's methods), some of them may only be |
128 |
> |
* called from within other ForkJoinTasks (as may be determined using |
129 |
> |
* method {@link #inForkJoinPool}). Attempts to invoke them in other |
130 |
> |
* contexts result in exceptions or errors, possibly including {@code |
131 |
> |
* ClassCastException}. |
132 |
|
* |
133 |
|
* <p>Method {@link #join} and its variants are appropriate for use |
134 |
|
* only when completion dependencies are acyclic; that is, the |
138 |
|
* supports other methods and techniques (for example the use of |
139 |
|
* {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that |
140 |
|
* may be of use in constructing custom subclasses for problems that |
141 |
< |
* are not statically structured as DAGs. |
141 |
> |
* are not statically structured as DAGs. To support such usages a |
142 |
> |
* ForkJoinTask may be atomically <em>tagged</em> with a {@code |
143 |
> |
* short} value using {@link #setForkJoinTaskTag} or {@link |
144 |
> |
* #compareAndSetForkJoinTaskTag} and checked using {@link |
145 |
> |
* #getForkJoinTaskTag}. The ForkJoinTask implementation does not |
146 |
> |
* use these {@code protected} methods or tags for any purpose, but |
147 |
> |
* they may be of use in the construction of specialized subclasses. |
148 |
> |
* For example, parallel graph traversals can use the supplied methods |
149 |
> |
* to avoid revisiting nodes/tasks that have already been processed. |
150 |
> |
* Also, completion based designs can use them to record that subtasks |
151 |
> |
* have completed. (Method names for tagging are bulky in part to |
152 |
> |
* encourage definition of methods that reflect their usage patterns.) |
153 |
|
* |
154 |
|
* <p>Most base support methods are {@code final}, to prevent |
155 |
|
* overriding of implementations that are intrinsically tied to the |
203 |
|
* The status field holds run control status bits packed into a |
204 |
|
* single int to minimize footprint and to ensure atomicity (via |
205 |
|
* CAS). Status is initially zero, and takes on nonnegative |
206 |
< |
* values until completed, upon which status holds value |
207 |
< |
* NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking |
208 |
< |
* waits by other threads have the SIGNAL bit set. Completion of |
209 |
< |
* a stolen task with SIGNAL set awakens any waiters via |
210 |
< |
* notifyAll. Even though suboptimal for some purposes, we use |
211 |
< |
* basic builtin wait/notify to take advantage of "monitor |
212 |
< |
* inflation" in JVMs that we would otherwise need to emulate to |
213 |
< |
* avoid adding further per-task bookkeeping overhead. We want |
214 |
< |
* these monitors to be "fat", i.e., not use biasing or thin-lock |
215 |
< |
* techniques, so use some odd coding idioms that tend to avoid |
216 |
< |
* them. |
206 |
> |
* values until completed, upon which status (anded with |
207 |
> |
* DONE_MASK) holds value NORMAL, CANCELLED, or EXCEPTIONAL. Tasks |
208 |
> |
* undergoing blocking waits by other threads have the SIGNAL bit |
209 |
> |
* set. Completion of a stolen task with SIGNAL set awakens any |
210 |
> |
* waiters via notifyAll. Even though suboptimal for some |
211 |
> |
* purposes, we use basic builtin wait/notify to take advantage of |
212 |
> |
* "monitor inflation" in JVMs that we would otherwise need to |
213 |
> |
* emulate to avoid adding further per-task bookkeeping overhead. |
214 |
> |
* We want these monitors to be "fat", i.e., not use biasing or |
215 |
> |
* thin-lock techniques, so use some odd coding idioms that tend |
216 |
> |
* to avoid them, mainly by arranging that every synchronized |
217 |
> |
* block performs a wait, notifyAll or both. |
218 |
> |
* |
219 |
> |
* These control bits occupy only (some of) the upper half (16 |
220 |
> |
* bits) of status field. The lower bits are used for user-defined |
221 |
> |
* tags. |
222 |
|
*/ |
223 |
|
|
224 |
|
/** The run status of this task */ |
225 |
|
volatile int status; // accessed directly by pool and workers |
226 |
< |
private static final int NORMAL = -1; |
227 |
< |
private static final int CANCELLED = -2; |
228 |
< |
private static final int EXCEPTIONAL = -3; |
229 |
< |
private static final int SIGNAL = 1; |
226 |
> |
static final int DONE_MASK = 0xf0000000; // mask out non-completion bits |
227 |
> |
static final int NORMAL = 0xf0000000; // must be negative |
228 |
> |
static final int CANCELLED = 0xc0000000; // must be < NORMAL |
229 |
> |
static final int EXCEPTIONAL = 0x80000000; // must be < CANCELLED |
230 |
> |
static final int SIGNAL = 0x00010000; // must be >= 1 << 16 |
231 |
> |
static final int SMASK = 0x0000ffff; // short bits for tags |
232 |
|
|
233 |
|
/** |
234 |
< |
* Marks completion and wakes up threads waiting to join this task, |
235 |
< |
* also clearing signal request bits. |
234 |
> |
* Marks completion and wakes up threads waiting to join this |
235 |
> |
* task. |
236 |
|
* |
237 |
|
* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL |
238 |
|
* @return completion status on exit |
241 |
|
for (int s;;) { |
242 |
|
if ((s = status) < 0) |
243 |
|
return s; |
244 |
< |
if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) { |
245 |
< |
if (s != 0) |
244 |
> |
if (U.compareAndSwapInt(this, STATUS, s, s | completion)) { |
245 |
> |
if ((s >>> 16) != 0) |
246 |
|
synchronized (this) { notifyAll(); } |
247 |
|
return completion; |
248 |
|
} |
250 |
|
} |
251 |
|
|
252 |
|
/** |
253 |
< |
* Tries to block a worker thread until completed or timed out. |
254 |
< |
* Uses Object.wait time argument conventions. |
255 |
< |
* May fail on contention or interrupt. |
253 |
> |
* Primary execution method for stolen tasks. Unless done, calls |
254 |
> |
* exec and records status if completed, but doesn't wait for |
255 |
> |
* completion otherwise. |
256 |
|
* |
257 |
< |
* @param millis if > 0, wait time. |
257 |
> |
* @return status on exit from this method |
258 |
|
*/ |
259 |
< |
final void tryAwaitDone(long millis) { |
260 |
< |
int s; |
261 |
< |
try { |
262 |
< |
if (((s = status) > 0 || |
263 |
< |
(s == 0 && |
264 |
< |
UNSAFE.compareAndSwapInt(this, statusOffset, 0, SIGNAL))) && |
265 |
< |
status > 0) { |
231 |
< |
synchronized (this) { |
232 |
< |
if (status > 0) |
233 |
< |
wait(millis); |
234 |
< |
} |
259 |
> |
final int doExec() { |
260 |
> |
int s; boolean completed; |
261 |
> |
if ((s = status) >= 0) { |
262 |
> |
try { |
263 |
> |
completed = exec(); |
264 |
> |
} catch (Throwable rex) { |
265 |
> |
return setExceptionalCompletion(rex); |
266 |
|
} |
267 |
< |
} catch (InterruptedException ie) { |
268 |
< |
// caller must check termination |
267 |
> |
if (completed) |
268 |
> |
s = setCompletion(NORMAL); |
269 |
|
} |
270 |
+ |
return s; |
271 |
+ |
} |
272 |
+ |
|
273 |
+ |
/** |
274 |
+ |
* Tries to set SIGNAL status unless already completed. Used by |
275 |
+ |
* ForkJoinPool. Other variants are directly incorporated into |
276 |
+ |
* externalAwaitDone etc. |
277 |
+ |
* |
278 |
+ |
* @return true if successful |
279 |
+ |
*/ |
280 |
+ |
final boolean trySetSignal() { |
281 |
+ |
int s = status; |
282 |
+ |
return s >= 0 && U.compareAndSwapInt(this, STATUS, s, s | SIGNAL); |
283 |
|
} |
284 |
|
|
285 |
|
/** |
287 |
|
* @return status upon completion |
288 |
|
*/ |
289 |
|
private int externalAwaitDone() { |
290 |
+ |
boolean interrupted = false; |
291 |
|
int s; |
292 |
< |
if ((s = status) >= 0) { |
293 |
< |
boolean interrupted = false; |
294 |
< |
synchronized (this) { |
295 |
< |
while ((s = status) >= 0) { |
251 |
< |
if (s == 0) |
252 |
< |
UNSAFE.compareAndSwapInt(this, statusOffset, |
253 |
< |
0, SIGNAL); |
254 |
< |
else { |
292 |
> |
while ((s = status) >= 0) { |
293 |
> |
if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { |
294 |
> |
synchronized (this) { |
295 |
> |
if (status >= 0) { |
296 |
|
try { |
297 |
|
wait(); |
298 |
|
} catch (InterruptedException ie) { |
299 |
|
interrupted = true; |
300 |
|
} |
301 |
|
} |
302 |
+ |
else |
303 |
+ |
notifyAll(); |
304 |
|
} |
305 |
|
} |
263 |
– |
if (interrupted) |
264 |
– |
Thread.currentThread().interrupt(); |
306 |
|
} |
307 |
+ |
if (interrupted) |
308 |
+ |
Thread.currentThread().interrupt(); |
309 |
|
return s; |
310 |
|
} |
311 |
|
|
312 |
|
/** |
313 |
< |
* Blocks a non-worker-thread until completion or interruption or timeout. |
313 |
> |
* Blocks a non-worker-thread until completion or interruption. |
314 |
|
*/ |
315 |
< |
private int externalInterruptibleAwaitDone(long millis) |
273 |
< |
throws InterruptedException { |
315 |
> |
private int externalInterruptibleAwaitDone() throws InterruptedException { |
316 |
|
int s; |
317 |
|
if (Thread.interrupted()) |
318 |
|
throw new InterruptedException(); |
319 |
< |
if ((s = status) >= 0) { |
320 |
< |
synchronized (this) { |
321 |
< |
while ((s = status) >= 0) { |
322 |
< |
if (s == 0) |
323 |
< |
UNSAFE.compareAndSwapInt(this, statusOffset, |
324 |
< |
0, SIGNAL); |
325 |
< |
else { |
284 |
< |
wait(millis); |
285 |
< |
if (millis > 0L) |
286 |
< |
break; |
287 |
< |
} |
319 |
> |
while ((s = status) >= 0) { |
320 |
> |
if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { |
321 |
> |
synchronized (this) { |
322 |
> |
if (status >= 0) |
323 |
> |
wait(); |
324 |
> |
else |
325 |
> |
notifyAll(); |
326 |
|
} |
327 |
|
} |
328 |
|
} |
330 |
|
} |
331 |
|
|
332 |
|
/** |
333 |
< |
* Primary execution method for stolen tasks. Unless done, calls |
334 |
< |
* exec and records status if completed, but doesn't wait for |
335 |
< |
* completion otherwise. |
336 |
< |
*/ |
299 |
< |
final void doExec() { |
300 |
< |
if (status >= 0) { |
301 |
< |
boolean completed; |
302 |
< |
try { |
303 |
< |
completed = exec(); |
304 |
< |
} catch (Throwable rex) { |
305 |
< |
setExceptionalCompletion(rex); |
306 |
< |
return; |
307 |
< |
} |
308 |
< |
if (completed) |
309 |
< |
setCompletion(NORMAL); // must be outside try block |
310 |
< |
} |
311 |
< |
} |
312 |
< |
|
313 |
< |
/** |
314 |
< |
* Primary mechanics for join, get, quietlyJoin. |
333 |
> |
* Implementation for join, get, quietlyJoin. Directly handles |
334 |
> |
* only cases of already-completed, external wait, and |
335 |
> |
* unfork+exec. Others are relayed to ForkJoinPool.awaitJoin. |
336 |
> |
* |
337 |
|
* @return status upon completion |
338 |
|
*/ |
339 |
|
private int doJoin() { |
340 |
< |
Thread t; ForkJoinWorkerThread w; int s; boolean completed; |
341 |
< |
if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) { |
342 |
< |
if ((s = status) < 0) |
343 |
< |
return s; |
344 |
< |
if ((w = (ForkJoinWorkerThread)t).unpushTask(this)) { |
345 |
< |
try { |
324 |
< |
completed = exec(); |
325 |
< |
} catch (Throwable rex) { |
326 |
< |
return setExceptionalCompletion(rex); |
327 |
< |
} |
328 |
< |
if (completed) |
329 |
< |
return setCompletion(NORMAL); |
340 |
> |
int s; Thread t; ForkJoinWorkerThread wt; ForkJoinPool.WorkQueue w; |
341 |
> |
if ((s = status) >= 0) { |
342 |
> |
if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) { |
343 |
> |
if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue). |
344 |
> |
tryUnpush(this) || (s = doExec()) >= 0) |
345 |
> |
s = wt.pool.awaitJoin(w, this); |
346 |
|
} |
347 |
< |
return w.joinTask(this); |
347 |
> |
else |
348 |
> |
s = externalAwaitDone(); |
349 |
|
} |
350 |
< |
else |
334 |
< |
return externalAwaitDone(); |
350 |
> |
return s; |
351 |
|
} |
352 |
|
|
353 |
|
/** |
354 |
< |
* Primary mechanics for invoke, quietlyInvoke. |
354 |
> |
* Implementation for invoke, quietlyInvoke. |
355 |
> |
* |
356 |
|
* @return status upon completion |
357 |
|
*/ |
358 |
|
private int doInvoke() { |
359 |
< |
int s; boolean completed; |
360 |
< |
if ((s = status) < 0) |
361 |
< |
return s; |
362 |
< |
try { |
363 |
< |
completed = exec(); |
364 |
< |
} catch (Throwable rex) { |
365 |
< |
return setExceptionalCompletion(rex); |
359 |
> |
int s; Thread t; ForkJoinWorkerThread wt; |
360 |
> |
if ((s = doExec()) >= 0) { |
361 |
> |
if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) |
362 |
> |
s = (wt = (ForkJoinWorkerThread)t).pool.awaitJoin(wt.workQueue, |
363 |
> |
this); |
364 |
> |
else |
365 |
> |
s = externalAwaitDone(); |
366 |
|
} |
367 |
< |
if (completed) |
351 |
< |
return setCompletion(NORMAL); |
352 |
< |
else |
353 |
< |
return doJoin(); |
367 |
> |
return s; |
368 |
|
} |
369 |
|
|
370 |
|
// Exception table support |
399 |
|
* any ForkJoinPool will call helpExpungeStaleExceptions when its |
400 |
|
* pool becomes isQuiescent. |
401 |
|
*/ |
402 |
< |
static final class ExceptionNode extends WeakReference<ForkJoinTask<?>>{ |
402 |
> |
static final class ExceptionNode extends WeakReference<ForkJoinTask<?>> { |
403 |
|
final Throwable ex; |
404 |
|
ExceptionNode next; |
405 |
|
final long thrower; // use id not ref to avoid weak cycles |
417 |
|
* @return status on exit |
418 |
|
*/ |
419 |
|
private int setExceptionalCompletion(Throwable ex) { |
420 |
< |
int h = System.identityHashCode(this); |
421 |
< |
final ReentrantLock lock = exceptionTableLock; |
422 |
< |
lock.lock(); |
423 |
< |
try { |
424 |
< |
expungeStaleExceptions(); |
425 |
< |
ExceptionNode[] t = exceptionTable; |
426 |
< |
int i = h & (t.length - 1); |
427 |
< |
for (ExceptionNode e = t[i]; ; e = e.next) { |
428 |
< |
if (e == null) { |
429 |
< |
t[i] = new ExceptionNode(this, ex, t[i]); |
430 |
< |
break; |
420 |
> |
int s; |
421 |
> |
if ((s = status) >= 0) { |
422 |
> |
int h = System.identityHashCode(this); |
423 |
> |
final ReentrantLock lock = exceptionTableLock; |
424 |
> |
lock.lock(); |
425 |
> |
try { |
426 |
> |
expungeStaleExceptions(); |
427 |
> |
ExceptionNode[] t = exceptionTable; |
428 |
> |
int i = h & (t.length - 1); |
429 |
> |
for (ExceptionNode e = t[i]; ; e = e.next) { |
430 |
> |
if (e == null) { |
431 |
> |
t[i] = new ExceptionNode(this, ex, t[i]); |
432 |
> |
break; |
433 |
> |
} |
434 |
> |
if (e.get() == this) // already present |
435 |
> |
break; |
436 |
|
} |
437 |
< |
if (e.get() == this) // already present |
438 |
< |
break; |
437 |
> |
} finally { |
438 |
> |
lock.unlock(); |
439 |
> |
} |
440 |
> |
s = setCompletion(EXCEPTIONAL); |
441 |
> |
} |
442 |
> |
ForkJoinTask<?> p = internalGetCompleter(); // propagate |
443 |
> |
if (p != null && p.status >= 0) |
444 |
> |
p.setExceptionalCompletion(ex); |
445 |
> |
return s; |
446 |
> |
} |
447 |
> |
|
448 |
> |
/** |
449 |
> |
* Exception propagation support for tasks with completers. |
450 |
> |
*/ |
451 |
> |
ForkJoinTask<?> internalGetCompleter() { |
452 |
> |
return null; |
453 |
> |
} |
454 |
> |
|
455 |
> |
/** |
456 |
> |
* Cancels, ignoring any exceptions thrown by cancel. Used during |
457 |
> |
* worker and pool shutdown. Cancel is spec'ed not to throw any |
458 |
> |
* exceptions, but if it does anyway, we have no recourse during |
459 |
> |
* shutdown, so guard against this case. |
460 |
> |
*/ |
461 |
> |
static final void cancelIgnoringExceptions(ForkJoinTask<?> t) { |
462 |
> |
if (t != null && t.status >= 0) { |
463 |
> |
try { |
464 |
> |
t.cancel(false); |
465 |
> |
} catch (Throwable ignore) { |
466 |
|
} |
421 |
– |
} finally { |
422 |
– |
lock.unlock(); |
467 |
|
} |
424 |
– |
return setCompletion(EXCEPTIONAL); |
468 |
|
} |
469 |
|
|
470 |
|
/** |
513 |
|
* @return the exception, or null if none |
514 |
|
*/ |
515 |
|
private Throwable getThrowableException() { |
516 |
< |
if (status != EXCEPTIONAL) |
516 |
> |
if ((status & DONE_MASK) != EXCEPTIONAL) |
517 |
|
return null; |
518 |
|
int h = System.identityHashCode(this); |
519 |
|
ExceptionNode e; |
531 |
|
Throwable ex; |
532 |
|
if (e == null || (ex = e.ex) == null) |
533 |
|
return null; |
534 |
< |
if (e.thrower != Thread.currentThread().getId()) { |
534 |
> |
if (false && e.thrower != Thread.currentThread().getId()) { |
535 |
|
Class<? extends Throwable> ec = ex.getClass(); |
536 |
|
try { |
537 |
|
Constructor<?> noArgCtor = null; |
598 |
|
} |
599 |
|
|
600 |
|
/** |
601 |
< |
* Report the result of invoke or join; called only upon |
559 |
< |
* non-normal return of internal versions. |
601 |
> |
* Throws exception, if any, associated with the given status. |
602 |
|
*/ |
603 |
< |
private V reportResult() { |
604 |
< |
int s; Throwable ex; |
605 |
< |
if ((s = status) == CANCELLED) |
606 |
< |
throw new CancellationException(); |
607 |
< |
if (s == EXCEPTIONAL && (ex = getThrowableException()) != null) |
608 |
< |
UNSAFE.throwException(ex); |
567 |
< |
return getRawResult(); |
603 |
> |
private void reportException(int s) { |
604 |
> |
Throwable ex = ((s == CANCELLED) ? new CancellationException() : |
605 |
> |
(s == EXCEPTIONAL) ? getThrowableException() : |
606 |
> |
null); |
607 |
> |
if (ex != null) |
608 |
> |
U.throwException(ex); |
609 |
|
} |
610 |
|
|
611 |
|
// public methods |
629 |
|
* @return {@code this}, to simplify usage |
630 |
|
*/ |
631 |
|
public final ForkJoinTask<V> fork() { |
632 |
< |
((ForkJoinWorkerThread) Thread.currentThread()) |
592 |
< |
.pushTask(this); |
632 |
> |
((ForkJoinWorkerThread)Thread.currentThread()).workQueue.push(this); |
633 |
|
return this; |
634 |
|
} |
635 |
|
|
645 |
|
* @return the computed result |
646 |
|
*/ |
647 |
|
public final V join() { |
648 |
< |
if (doJoin() != NORMAL) |
649 |
< |
return reportResult(); |
650 |
< |
else |
651 |
< |
return getRawResult(); |
648 |
> |
int s; |
649 |
> |
if ((s = doJoin() & DONE_MASK) != NORMAL) |
650 |
> |
reportException(s); |
651 |
> |
return getRawResult(); |
652 |
|
} |
653 |
|
|
654 |
|
/** |
660 |
|
* @return the computed result |
661 |
|
*/ |
662 |
|
public final V invoke() { |
663 |
< |
if (doInvoke() != NORMAL) |
664 |
< |
return reportResult(); |
665 |
< |
else |
666 |
< |
return getRawResult(); |
663 |
> |
int s; |
664 |
> |
if ((s = doInvoke() & DONE_MASK) != NORMAL) |
665 |
> |
reportException(s); |
666 |
> |
return getRawResult(); |
667 |
|
} |
668 |
|
|
669 |
|
/** |
690 |
|
* @throws NullPointerException if any task is null |
691 |
|
*/ |
692 |
|
public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) { |
693 |
+ |
int s1, s2; |
694 |
|
t2.fork(); |
695 |
< |
t1.invoke(); |
696 |
< |
t2.join(); |
695 |
> |
if ((s1 = t1.doInvoke() & DONE_MASK) != NORMAL) |
696 |
> |
t1.reportException(s1); |
697 |
> |
if ((s2 = t2.doJoin() & DONE_MASK) != NORMAL) |
698 |
> |
t2.reportException(s2); |
699 |
|
} |
700 |
|
|
701 |
|
/** |
743 |
|
} |
744 |
|
} |
745 |
|
if (ex != null) |
746 |
< |
UNSAFE.throwException(ex); |
746 |
> |
U.throwException(ex); |
747 |
|
} |
748 |
|
|
749 |
|
/** |
800 |
|
} |
801 |
|
} |
802 |
|
if (ex != null) |
803 |
< |
UNSAFE.throwException(ex); |
803 |
> |
U.throwException(ex); |
804 |
|
return tasks; |
805 |
|
} |
806 |
|
|
832 |
|
* @return {@code true} if this task is now cancelled |
833 |
|
*/ |
834 |
|
public boolean cancel(boolean mayInterruptIfRunning) { |
835 |
< |
return setCompletion(CANCELLED) == CANCELLED; |
793 |
< |
} |
794 |
< |
|
795 |
< |
/** |
796 |
< |
* Cancels, ignoring any exceptions thrown by cancel. Used during |
797 |
< |
* worker and pool shutdown. Cancel is spec'ed not to throw any |
798 |
< |
* exceptions, but if it does anyway, we have no recourse during |
799 |
< |
* shutdown, so guard against this case. |
800 |
< |
*/ |
801 |
< |
final void cancelIgnoringExceptions() { |
802 |
< |
try { |
803 |
< |
cancel(false); |
804 |
< |
} catch (Throwable ignore) { |
805 |
< |
} |
835 |
> |
return (setCompletion(CANCELLED) & DONE_MASK) == CANCELLED; |
836 |
|
} |
837 |
|
|
838 |
|
public final boolean isDone() { |
840 |
|
} |
841 |
|
|
842 |
|
public final boolean isCancelled() { |
843 |
< |
return status == CANCELLED; |
843 |
> |
return (status & DONE_MASK) == CANCELLED; |
844 |
|
} |
845 |
|
|
846 |
|
/** |
860 |
|
* exception and was not cancelled |
861 |
|
*/ |
862 |
|
public final boolean isCompletedNormally() { |
863 |
< |
return status == NORMAL; |
863 |
> |
return (status & DONE_MASK) == NORMAL; |
864 |
|
} |
865 |
|
|
866 |
|
/** |
871 |
|
* @return the exception, or {@code null} if none |
872 |
|
*/ |
873 |
|
public final Throwable getException() { |
874 |
< |
int s = status; |
874 |
> |
int s = status & DONE_MASK; |
875 |
|
return ((s >= NORMAL) ? null : |
876 |
|
(s == CANCELLED) ? new CancellationException() : |
877 |
|
getThrowableException()); |
921 |
|
} |
922 |
|
|
923 |
|
/** |
924 |
+ |
* Completes this task normally without setting a value. The most |
925 |
+ |
* recent value established by {@link #setRawResult} (or {@code |
926 |
+ |
* null} by default) will be returned as the result of subsequent |
927 |
+ |
* invocations of {@code join} and related operations. |
928 |
+ |
* |
929 |
+ |
* @since 1.8 |
930 |
+ |
*/ |
931 |
+ |
public final void quietlyComplete() { |
932 |
+ |
setCompletion(NORMAL); |
933 |
+ |
} |
934 |
+ |
|
935 |
+ |
/** |
936 |
|
* Waits if necessary for the computation to complete, and then |
937 |
|
* retrieves its result. |
938 |
|
* |
945 |
|
*/ |
946 |
|
public final V get() throws InterruptedException, ExecutionException { |
947 |
|
int s = (Thread.currentThread() instanceof ForkJoinWorkerThread) ? |
948 |
< |
doJoin() : externalInterruptibleAwaitDone(0L); |
948 |
> |
doJoin() : externalInterruptibleAwaitDone(); |
949 |
|
Throwable ex; |
950 |
< |
if (s == CANCELLED) |
950 |
> |
if ((s &= DONE_MASK) == CANCELLED) |
951 |
|
throw new CancellationException(); |
952 |
|
if (s == EXCEPTIONAL && (ex = getThrowableException()) != null) |
953 |
|
throw new ExecutionException(ex); |
970 |
|
*/ |
971 |
|
public final V get(long timeout, TimeUnit unit) |
972 |
|
throws InterruptedException, ExecutionException, TimeoutException { |
973 |
< |
Thread t = Thread.currentThread(); |
974 |
< |
if (t instanceof ForkJoinWorkerThread) { |
975 |
< |
ForkJoinWorkerThread w = (ForkJoinWorkerThread) t; |
976 |
< |
long nanos = unit.toNanos(timeout); |
977 |
< |
if (status >= 0) { |
978 |
< |
boolean completed = false; |
979 |
< |
if (w.unpushTask(this)) { |
980 |
< |
try { |
981 |
< |
completed = exec(); |
982 |
< |
} catch (Throwable rex) { |
983 |
< |
setExceptionalCompletion(rex); |
973 |
> |
if (Thread.interrupted()) |
974 |
> |
throw new InterruptedException(); |
975 |
> |
// Messy in part because we measure in nanosecs, but wait in millisecs |
976 |
> |
int s; long ns, ms; |
977 |
> |
if ((s = status) >= 0 && (ns = unit.toNanos(timeout)) > 0L) { |
978 |
> |
long deadline = System.nanoTime() + ns; |
979 |
> |
ForkJoinPool p = null; |
980 |
> |
ForkJoinPool.WorkQueue w = null; |
981 |
> |
Thread t = Thread.currentThread(); |
982 |
> |
if (t instanceof ForkJoinWorkerThread) { |
983 |
> |
ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t; |
984 |
> |
p = wt.pool; |
985 |
> |
w = wt.workQueue; |
986 |
> |
s = p.helpJoinOnce(w, this); // no retries on failure |
987 |
> |
} |
988 |
> |
boolean canBlock = false; |
989 |
> |
boolean interrupted = false; |
990 |
> |
try { |
991 |
> |
while ((s = status) >= 0) { |
992 |
> |
if (w != null && w.runState < 0) |
993 |
> |
cancelIgnoringExceptions(this); |
994 |
> |
else if (!canBlock) { |
995 |
> |
if (p == null || p.tryCompensate(this, null)) |
996 |
> |
canBlock = true; |
997 |
> |
} |
998 |
> |
else { |
999 |
> |
if ((ms = TimeUnit.NANOSECONDS.toMillis(ns)) > 0L && |
1000 |
> |
U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) { |
1001 |
> |
synchronized (this) { |
1002 |
> |
if (status >= 0) { |
1003 |
> |
try { |
1004 |
> |
wait(ms); |
1005 |
> |
} catch (InterruptedException ie) { |
1006 |
> |
if (p == null) |
1007 |
> |
interrupted = true; |
1008 |
> |
} |
1009 |
> |
} |
1010 |
> |
else |
1011 |
> |
notifyAll(); |
1012 |
> |
} |
1013 |
> |
} |
1014 |
> |
if ((s = status) < 0 || interrupted || |
1015 |
> |
(ns = deadline - System.nanoTime()) <= 0L) |
1016 |
> |
break; |
1017 |
|
} |
1018 |
|
} |
1019 |
< |
if (completed) |
1020 |
< |
setCompletion(NORMAL); |
1021 |
< |
else if (status >= 0 && nanos > 0) |
947 |
< |
w.pool.timedAwaitJoin(this, nanos); |
1019 |
> |
} finally { |
1020 |
> |
if (p != null && canBlock) |
1021 |
> |
p.incrementActiveCount(); |
1022 |
|
} |
1023 |
+ |
if (interrupted) |
1024 |
+ |
throw new InterruptedException(); |
1025 |
|
} |
1026 |
< |
else { |
951 |
< |
long millis = unit.toMillis(timeout); |
952 |
< |
if (millis > 0) |
953 |
< |
externalInterruptibleAwaitDone(millis); |
954 |
< |
} |
955 |
< |
int s = status; |
956 |
< |
if (s != NORMAL) { |
1026 |
> |
if ((s &= DONE_MASK) != NORMAL) { |
1027 |
|
Throwable ex; |
1028 |
|
if (s == CANCELLED) |
1029 |
|
throw new CancellationException(); |
1068 |
|
* ClassCastException}. |
1069 |
|
*/ |
1070 |
|
public static void helpQuiesce() { |
1071 |
< |
((ForkJoinWorkerThread) Thread.currentThread()) |
1072 |
< |
.helpQuiescePool(); |
1071 |
> |
ForkJoinWorkerThread wt = |
1072 |
> |
(ForkJoinWorkerThread)Thread.currentThread(); |
1073 |
> |
wt.pool.helpQuiescePool(wt.workQueue); |
1074 |
|
} |
1075 |
|
|
1076 |
|
/** |
1090 |
|
* setRawResult(null)}. |
1091 |
|
*/ |
1092 |
|
public void reinitialize() { |
1093 |
< |
if (status == EXCEPTIONAL) |
1093 |
> |
if ((status & DONE_MASK) == EXCEPTIONAL) |
1094 |
|
clearExceptionalCompletion(); |
1095 |
|
else |
1096 |
|
status = 0; |
1138 |
|
* @return {@code true} if unforked |
1139 |
|
*/ |
1140 |
|
public boolean tryUnfork() { |
1141 |
< |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1142 |
< |
.unpushTask(this); |
1141 |
> |
return ((ForkJoinWorkerThread)Thread.currentThread()) |
1142 |
> |
.workQueue.tryUnpush(this); |
1143 |
|
} |
1144 |
|
|
1145 |
|
/** |
1158 |
|
*/ |
1159 |
|
public static int getQueuedTaskCount() { |
1160 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1161 |
< |
.getQueueSize(); |
1161 |
> |
.workQueue.queueSize(); |
1162 |
|
} |
1163 |
|
|
1164 |
|
/** |
1180 |
|
* @return the surplus number of tasks, which may be negative |
1181 |
|
*/ |
1182 |
|
public static int getSurplusQueuedTaskCount() { |
1183 |
< |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1184 |
< |
.getEstimatedSurplusTaskCount(); |
1183 |
> |
/* |
1184 |
> |
* The aim of this method is to return a cheap heuristic guide |
1185 |
> |
* for task partitioning when programmers, frameworks, tools, |
1186 |
> |
* or languages have little or no idea about task granularity. |
1187 |
> |
* In essence by offering this method, we ask users only about |
1188 |
> |
* tradeoffs in overhead vs expected throughput and its |
1189 |
> |
* variance, rather than how finely to partition tasks. |
1190 |
> |
* |
1191 |
> |
* In a steady state strict (tree-structured) computation, |
1192 |
> |
* each thread makes available for stealing enough tasks for |
1193 |
> |
* other threads to remain active. Inductively, if all threads |
1194 |
> |
* play by the same rules, each thread should make available |
1195 |
> |
* only a constant number of tasks. |
1196 |
> |
* |
1197 |
> |
* The minimum useful constant is just 1. But using a value of |
1198 |
> |
* 1 would require immediate replenishment upon each steal to |
1199 |
> |
* maintain enough tasks, which is infeasible. Further, |
1200 |
> |
* partitionings/granularities of offered tasks should |
1201 |
> |
* minimize steal rates, which in general means that threads |
1202 |
> |
* nearer the top of computation tree should generate more |
1203 |
> |
* than those nearer the bottom. In perfect steady state, each |
1204 |
> |
* thread is at approximately the same level of computation |
1205 |
> |
* tree. However, producing extra tasks amortizes the |
1206 |
> |
* uncertainty of progress and diffusion assumptions. |
1207 |
> |
* |
1208 |
> |
* So, users will want to use values larger, but not much |
1209 |
> |
* larger than 1 to both smooth over transient shortages and |
1210 |
> |
* hedge against uneven progress; as traded off against the |
1211 |
> |
* cost of extra task overhead. We leave the user to pick a |
1212 |
> |
* threshold value to compare with the results of this call to |
1213 |
> |
* guide decisions, but recommend values such as 3. |
1214 |
> |
* |
1215 |
> |
* When all threads are active, it is on average OK to |
1216 |
> |
* estimate surplus strictly locally. In steady-state, if one |
1217 |
> |
* thread is maintaining say 2 surplus tasks, then so are |
1218 |
> |
* others. So we can just use estimated queue length. |
1219 |
> |
* However, this strategy alone leads to serious mis-estimates |
1220 |
> |
* in some non-steady-state conditions (ramp-up, ramp-down, |
1221 |
> |
* other stalls). We can detect many of these by further |
1222 |
> |
* considering the number of "idle" threads, that are known to |
1223 |
> |
* have zero queued tasks, so compensate by a factor of |
1224 |
> |
* (#idle/#active) threads. |
1225 |
> |
*/ |
1226 |
> |
ForkJoinWorkerThread wt = |
1227 |
> |
(ForkJoinWorkerThread)Thread.currentThread(); |
1228 |
> |
return wt.workQueue.queueSize() - wt.pool.idlePerActive(); |
1229 |
|
} |
1230 |
|
|
1231 |
|
// Extension methods |
1251 |
|
protected abstract void setRawResult(V value); |
1252 |
|
|
1253 |
|
/** |
1254 |
< |
* Immediately performs the base action of this task. This method |
1255 |
< |
* is designed to support extensions, and should not in general be |
1256 |
< |
* called otherwise. The return value controls whether this task |
1257 |
< |
* is considered to be done normally. It may return false in |
1254 |
> |
* Immediately performs the base action of this task and returns |
1255 |
> |
* true if, upon return from this method, this task is guaranteed |
1256 |
> |
* to have completed normally. This method may return false |
1257 |
> |
* otherwise, to indicate that this task is not necessarily |
1258 |
> |
* complete (or is not known to be complete), for example in |
1259 |
|
* asynchronous actions that require explicit invocations of |
1260 |
< |
* {@link #complete} to become joinable. It may also throw an |
1261 |
< |
* (unchecked) exception to indicate abnormal exit. |
1260 |
> |
* completion methods. This method may also throw an (unchecked) |
1261 |
> |
* exception to indicate abnormal exit. This method is designed to |
1262 |
> |
* support extensions, and should not in general be called |
1263 |
> |
* otherwise. |
1264 |
|
* |
1265 |
< |
* @return {@code true} if completed normally |
1265 |
> |
* @return {@code true} if this task is known to have completed normally |
1266 |
|
*/ |
1267 |
|
protected abstract boolean exec(); |
1268 |
|
|
1285 |
|
* @return the next task, or {@code null} if none are available |
1286 |
|
*/ |
1287 |
|
protected static ForkJoinTask<?> peekNextLocalTask() { |
1288 |
< |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1171 |
< |
.peekTask(); |
1288 |
> |
return ((ForkJoinWorkerThread) Thread.currentThread()).workQueue.peek(); |
1289 |
|
} |
1290 |
|
|
1291 |
|
/** |
1304 |
|
*/ |
1305 |
|
protected static ForkJoinTask<?> pollNextLocalTask() { |
1306 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1307 |
< |
.pollLocalTask(); |
1307 |
> |
.workQueue.nextLocalTask(); |
1308 |
|
} |
1309 |
|
|
1310 |
|
/** |
1326 |
|
* @return a task, or {@code null} if none are available |
1327 |
|
*/ |
1328 |
|
protected static ForkJoinTask<?> pollTask() { |
1329 |
< |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1330 |
< |
.pollTask(); |
1329 |
> |
ForkJoinWorkerThread wt = |
1330 |
> |
(ForkJoinWorkerThread)Thread.currentThread(); |
1331 |
> |
return wt.pool.nextTaskFor(wt.workQueue); |
1332 |
> |
} |
1333 |
> |
|
1334 |
> |
// tag operations |
1335 |
> |
|
1336 |
> |
/** |
1337 |
> |
* Returns the tag for this task. |
1338 |
> |
* |
1339 |
> |
* @return the tag for this task |
1340 |
> |
* @since 1.8 |
1341 |
> |
*/ |
1342 |
> |
public final short getForkJoinTaskTag() { |
1343 |
> |
return (short)status; |
1344 |
> |
} |
1345 |
> |
|
1346 |
> |
/** |
1347 |
> |
* Atomically sets the tag value for this task. |
1348 |
> |
* |
1349 |
> |
* @param tag the tag value |
1350 |
> |
* @return the previous value of the tag |
1351 |
> |
* @since 1.8 |
1352 |
> |
*/ |
1353 |
> |
public final short setForkJoinTaskTag(short tag) { |
1354 |
> |
for (int s;;) { |
1355 |
> |
if (U.compareAndSwapInt(this, STATUS, s = status, |
1356 |
> |
(s & ~SMASK) | (tag & SMASK))) |
1357 |
> |
return (short)s; |
1358 |
> |
} |
1359 |
> |
} |
1360 |
> |
|
1361 |
> |
/** |
1362 |
> |
* Atomically conditionally sets the tag value for this task. |
1363 |
> |
* Among other applications, tags can be used as visit markers |
1364 |
> |
* in tasks operating on graphs, as in methods that check: {@code |
1365 |
> |
* if (task.compareAndSetForkJoinTaskTag((short)0, (short)1))} |
1366 |
> |
* before processing, otherwise exiting because the node has |
1367 |
> |
* already been visited. |
1368 |
> |
* |
1369 |
> |
* @param e the expected tag value |
1370 |
> |
* @param tag the new tag value |
1371 |
> |
* @return true if successful; i.e., the current value was |
1372 |
> |
* equal to e and is now tag. |
1373 |
> |
* @since 1.8 |
1374 |
> |
*/ |
1375 |
> |
public final boolean compareAndSetForkJoinTaskTag(short e, short tag) { |
1376 |
> |
for (int s;;) { |
1377 |
> |
if ((short)(s = status) != e) |
1378 |
> |
return false; |
1379 |
> |
if (U.compareAndSwapInt(this, STATUS, s, |
1380 |
> |
(s & ~SMASK) | (tag & SMASK))) |
1381 |
> |
return true; |
1382 |
> |
} |
1383 |
|
} |
1384 |
|
|
1385 |
|
/** |
1390 |
|
static final class AdaptedRunnable<T> extends ForkJoinTask<T> |
1391 |
|
implements RunnableFuture<T> { |
1392 |
|
final Runnable runnable; |
1224 |
– |
final T resultOnCompletion; |
1393 |
|
T result; |
1394 |
|
AdaptedRunnable(Runnable runnable, T result) { |
1395 |
|
if (runnable == null) throw new NullPointerException(); |
1396 |
|
this.runnable = runnable; |
1397 |
< |
this.resultOnCompletion = result; |
1397 |
> |
this.result = result; // OK to set this even before completion |
1398 |
|
} |
1399 |
< |
public T getRawResult() { return result; } |
1400 |
< |
public void setRawResult(T v) { result = v; } |
1401 |
< |
public boolean exec() { |
1402 |
< |
runnable.run(); |
1403 |
< |
result = resultOnCompletion; |
1404 |
< |
return true; |
1399 |
> |
public final T getRawResult() { return result; } |
1400 |
> |
public final void setRawResult(T v) { result = v; } |
1401 |
> |
public final boolean exec() { runnable.run(); return true; } |
1402 |
> |
public final void run() { invoke(); } |
1403 |
> |
private static final long serialVersionUID = 5232453952276885070L; |
1404 |
> |
} |
1405 |
> |
|
1406 |
> |
/** |
1407 |
> |
* Adaptor for Runnables without results |
1408 |
> |
*/ |
1409 |
> |
static final class AdaptedRunnableAction extends ForkJoinTask<Void> |
1410 |
> |
implements RunnableFuture<Void> { |
1411 |
> |
final Runnable runnable; |
1412 |
> |
AdaptedRunnableAction(Runnable runnable) { |
1413 |
> |
if (runnable == null) throw new NullPointerException(); |
1414 |
> |
this.runnable = runnable; |
1415 |
|
} |
1416 |
< |
public void run() { invoke(); } |
1416 |
> |
public final Void getRawResult() { return null; } |
1417 |
> |
public final void setRawResult(Void v) { } |
1418 |
> |
public final boolean exec() { runnable.run(); return true; } |
1419 |
> |
public final void run() { invoke(); } |
1420 |
|
private static final long serialVersionUID = 5232453952276885070L; |
1421 |
|
} |
1422 |
|
|
1431 |
|
if (callable == null) throw new NullPointerException(); |
1432 |
|
this.callable = callable; |
1433 |
|
} |
1434 |
< |
public T getRawResult() { return result; } |
1435 |
< |
public void setRawResult(T v) { result = v; } |
1436 |
< |
public boolean exec() { |
1434 |
> |
public final T getRawResult() { return result; } |
1435 |
> |
public final void setRawResult(T v) { result = v; } |
1436 |
> |
public final boolean exec() { |
1437 |
|
try { |
1438 |
|
result = callable.call(); |
1439 |
|
return true; |
1445 |
|
throw new RuntimeException(ex); |
1446 |
|
} |
1447 |
|
} |
1448 |
< |
public void run() { invoke(); } |
1448 |
> |
public final void run() { invoke(); } |
1449 |
|
private static final long serialVersionUID = 2838392045355241008L; |
1450 |
|
} |
1451 |
|
|
1458 |
|
* @return the task |
1459 |
|
*/ |
1460 |
|
public static ForkJoinTask<?> adapt(Runnable runnable) { |
1461 |
< |
return new AdaptedRunnable<Void>(runnable, null); |
1461 |
> |
return new AdaptedRunnableAction(runnable); |
1462 |
|
} |
1463 |
|
|
1464 |
|
/** |
1492 |
|
private static final long serialVersionUID = -7721805057305804111L; |
1493 |
|
|
1494 |
|
/** |
1495 |
< |
* Saves the state to a stream (that is, serializes it). |
1495 |
> |
* Saves this task to a stream (that is, serializes it). |
1496 |
|
* |
1497 |
|
* @serialData the current run status and the exception thrown |
1498 |
|
* during execution, or {@code null} if none |
1318 |
– |
* @param s the stream |
1499 |
|
*/ |
1500 |
|
private void writeObject(java.io.ObjectOutputStream s) |
1501 |
|
throws java.io.IOException { |
1504 |
|
} |
1505 |
|
|
1506 |
|
/** |
1507 |
< |
* Reconstitutes the instance from a stream (that is, deserializes it). |
1328 |
< |
* |
1329 |
< |
* @param s the stream |
1507 |
> |
* Reconstitutes this task from a stream (that is, deserializes it). |
1508 |
|
*/ |
1509 |
|
private void readObject(java.io.ObjectInputStream s) |
1510 |
|
throws java.io.IOException, ClassNotFoundException { |
1515 |
|
} |
1516 |
|
|
1517 |
|
// Unsafe mechanics |
1518 |
< |
private static final sun.misc.Unsafe UNSAFE; |
1519 |
< |
private static final long statusOffset; |
1518 |
> |
private static final sun.misc.Unsafe U; |
1519 |
> |
private static final long STATUS; |
1520 |
|
static { |
1521 |
|
exceptionTableLock = new ReentrantLock(); |
1522 |
|
exceptionTableRefQueue = new ReferenceQueue<Object>(); |
1523 |
|
exceptionTable = new ExceptionNode[EXCEPTION_MAP_CAPACITY]; |
1524 |
|
try { |
1525 |
< |
UNSAFE = getUnsafe(); |
1526 |
< |
statusOffset = UNSAFE.objectFieldOffset |
1525 |
> |
U = getUnsafe(); |
1526 |
> |
STATUS = U.objectFieldOffset |
1527 |
|
(ForkJoinTask.class.getDeclaredField("status")); |
1528 |
|
} catch (Exception e) { |
1529 |
|
throw new Error(e); |