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Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.84 by jsr166, Sat Jan 28 04:32:25 2012 UTC vs.
Revision 1.92 by dl, Wed Oct 31 12:49:24 2012 UTC

# Line 5 | Line 5
5   */
6  
7   package jsr166y;
8 +
9   import java.io.Serializable;
10   import java.util.Collection;
11   import java.util.List;
# Line 29 | Line 30 | import java.lang.reflect.Constructor;
30   * subtasks may be hosted by a small number of actual threads in a
31   * ForkJoinPool, at the price of some usage limitations.
32   *
33 < * <p>A "main" {@code ForkJoinTask} begins execution when submitted
34 < * to a {@link ForkJoinPool}.  Once started, it will usually in turn
35 < * start other subtasks.  As indicated by the name of this class,
36 < * many programs using {@code ForkJoinTask} employ only methods
37 < * {@link #fork} and {@link #join}, or derivatives such as {@link
33 > * <p>A "main" {@code ForkJoinTask} begins execution when it is
34 > * explicitly submitted to a {@link ForkJoinPool}, or, if not already
35 > * engaged in a ForkJoin computation, commenced in the {@link
36 > * ForkJoinPool#commonPool} via {@link #fork}, {@link #invoke}, or
37 > * related methods.  Once started, it will usually in turn start other
38 > * subtasks.  As indicated by the name of this class, many programs
39 > * using {@code ForkJoinTask} employ only methods {@link #fork} and
40 > * {@link #join}, or derivatives such as {@link
41   * #invokeAll(ForkJoinTask...) invokeAll}.  However, this class also
42   * provides a number of other methods that can come into play in
43 < * advanced usages, as well as extension mechanics that allow
44 < * support of new forms of fork/join processing.
43 > * advanced usages, as well as extension mechanics that allow support
44 > * of new forms of fork/join processing.
45   *
46   * <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}.
47   * The efficiency of {@code ForkJoinTask}s stems from a set of
# Line 70 | Line 74 | import java.lang.reflect.Constructor;
74   * but doing do requires three further considerations: (1) Completion
75   * of few if any <em>other</em> tasks should be dependent on a task
76   * that blocks on external synchronization or IO. Event-style async
77 < * tasks that are never joined often fall into this category.  (2) To
78 < * minimize resource impact, tasks should be small; ideally performing
79 < * only the (possibly) blocking action. (3) Unless the {@link
77 > * tasks that are never joined (for example, those subclassing {@link
78 > * CountedCompleter}) often fall into this category.  (2) To minimize
79 > * resource impact, tasks should be small; ideally performing only the
80 > * (possibly) blocking action. (3) Unless the {@link
81   * ForkJoinPool.ManagedBlocker} API is used, or the number of possibly
82   * blocked tasks is known to be less than the pool's {@link
83   * ForkJoinPool#getParallelism} level, the pool cannot guarantee that
# Line 115 | Line 120 | import java.lang.reflect.Constructor;
120   * <p>The ForkJoinTask class is not usually directly subclassed.
121   * Instead, you subclass one of the abstract classes that support a
122   * particular style of fork/join processing, typically {@link
123 < * RecursiveAction} for computations that do not return results, or
124 < * {@link RecursiveTask} for those that do.  Normally, a concrete
125 < * ForkJoinTask subclass declares fields comprising its parameters,
126 < * established in a constructor, and then defines a {@code compute}
127 < * method that somehow uses the control methods supplied by this base
128 < * class. While these methods have {@code public} access (to allow
129 < * instances of different task subclasses to call each other's
125 < * methods), some of them may only be called from within other
126 < * ForkJoinTasks (as may be determined using method {@link
127 < * #inForkJoinPool}).  Attempts to invoke them in other contexts
128 < * result in exceptions or errors, possibly including
129 < * {@code ClassCastException}.
123 > * RecursiveAction} for most computations that do not return results,
124 > * {@link RecursiveTask} for those that do, and {@link
125 > * CountedCompleter} for those in which completed actions trigger
126 > * other actions.  Normally, a concrete ForkJoinTask subclass declares
127 > * fields comprising its parameters, established in a constructor, and
128 > * then defines a {@code compute} method that somehow uses the control
129 > * methods supplied by this base class.
130   *
131   * <p>Method {@link #join} and its variants are appropriate for use
132   * only when completion dependencies are acyclic; that is, the
# Line 137 | Line 137 | import java.lang.reflect.Constructor;
137   * {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that
138   * may be of use in constructing custom subclasses for problems that
139   * are not statically structured as DAGs. To support such usages a
140 < * ForkJoinTask may be atomically <em>marked</em> using {@link
141 < * #markForkJoinTask} and checked for marking using {@link
142 < * #isMarkedForkJoinTask}. The ForkJoinTask implementation does not
143 < * use these {@code protected} methods or marks for any purpose, but
144 < * they may be of use in the construction of specialized subclasses.
145 < * For example, parallel graph traversals can use the supplied methods
146 < * to avoid revisiting nodes/tasks that have already been processed.
147 < * Also, completion based designs can use them to record that one
148 < * subtask has completed. (Method names for marking are bulky in part
149 < * to encourage definition of methods that reflect their usage
150 < * patterns.)
140 > * ForkJoinTask may be atomically <em>tagged</em> with a {@code short}
141 > * value using {@link #setForkJoinTaskTag} or {@link
142 > * #compareAndSetForkJoinTaskTag} and checked using {@link
143 > * #getForkJoinTaskTag}. The ForkJoinTask implementation does not use
144 > * these {@code protected} methods or tags for any purpose, but they
145 > * may be of use in the construction of specialized subclasses.  For
146 > * example, parallel graph traversals can use the supplied methods to
147 > * avoid revisiting nodes/tasks that have already been processed.
148 > * (Method names for tagging are bulky in part to encourage definition
149 > * of methods that reflect their usage patterns.)
150   *
151   * <p>Most base support methods are {@code final}, to prevent
152   * overriding of implementations that are intrinsically tied to the
# Line 197 | Line 196 | public abstract class ForkJoinTask<V> im
196       * methods in a way that flows well in javadocs.
197       */
198  
200    /**
201     * The number of times to try to help join a task without any
202     * apparent progress before giving up and blocking. The value is
203     * arbitrary but should be large enough to cope with transient
204     * stalls (due to GC etc) that can cause helping methods not to be
205     * able to proceed because other workers have not progressed to
206     * the point where subtasks can be found or taken.
207     */
208    private static final int HELP_RETRIES = 32;
209
199      /*
200       * The status field holds run control status bits packed into a
201       * single int to minimize footprint and to ensure atomicity (via
202       * CAS).  Status is initially zero, and takes on nonnegative
203 <     * values until completed, upon which status holds value
204 <     * NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking
205 <     * waits by other threads have the SIGNAL bit set.  Completion of
206 <     * a stolen task with SIGNAL set awakens any waiters via
207 <     * notifyAll. Even though suboptimal for some purposes, we use
208 <     * basic builtin wait/notify to take advantage of "monitor
209 <     * inflation" in JVMs that we would otherwise need to emulate to
210 <     * avoid adding further per-task bookkeeping overhead.  We want
211 <     * these monitors to be "fat", i.e., not use biasing or thin-lock
212 <     * techniques, so use some odd coding idioms that tend to avoid
213 <     * them.
203 >     * values until completed, upon which status (anded with
204 >     * DONE_MASK) holds value NORMAL, CANCELLED, or EXCEPTIONAL. Tasks
205 >     * undergoing blocking waits by other threads have the SIGNAL bit
206 >     * set.  Completion of a stolen task with SIGNAL set awakens any
207 >     * waiters via notifyAll. Even though suboptimal for some
208 >     * purposes, we use basic builtin wait/notify to take advantage of
209 >     * "monitor inflation" in JVMs that we would otherwise need to
210 >     * emulate to avoid adding further per-task bookkeeping overhead.
211 >     * We want these monitors to be "fat", i.e., not use biasing or
212 >     * thin-lock techniques, so use some odd coding idioms that tend
213 >     * to avoid them, mainly by arranging that every synchronized
214 >     * block performs a wait, notifyAll or both.
215 >     *
216 >     * These control bits occupy only (some of) the upper half (16
217 >     * bits) of status field. The lower bits are used for user-defined
218 >     * tags.
219       */
220  
221      /** The run status of this task */
222      volatile int status; // accessed directly by pool and workers
223 <    static final int NORMAL      = 0xfffffffc;  // negative with low 2 bits 0
224 <    static final int CANCELLED   = 0xfffffff8;  // must be < NORMAL
225 <    static final int EXCEPTIONAL = 0xfffffff4;  // must be < CANCELLED
226 <    static final int SIGNAL      = 0x00000001;
227 <    static final int MARKED      = 0x00000002;
223 >    static final int DONE_MASK   = 0xf0000000;  // mask out non-completion bits
224 >    static final int NORMAL      = 0xf0000000;  // must be negative
225 >    static final int CANCELLED   = 0xc0000000;  // must be < NORMAL
226 >    static final int EXCEPTIONAL = 0x80000000;  // must be < CANCELLED
227 >    static final int SIGNAL      = 0x00010000;  // must be >= 1 << 16
228 >    static final int SMASK       = 0x0000ffff;  // short bits for tags
229  
230      /**
231       * Marks completion and wakes up threads waiting to join this
232 <     * task, also clearing signal request bits. A specialization for
238 <     * NORMAL completion is in method doExec.
232 >     * task.
233       *
234       * @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
235       * @return completion status on exit
# Line 244 | Line 238 | public abstract class ForkJoinTask<V> im
238          for (int s;;) {
239              if ((s = status) < 0)
240                  return s;
241 <            if (U.compareAndSwapInt(this, STATUS, s, (s & ~SIGNAL)|completion)) {
242 <                if ((s & SIGNAL) != 0)
241 >            if (U.compareAndSwapInt(this, STATUS, s, s | completion)) {
242 >                if ((s >>> 16) != 0)
243                      synchronized (this) { notifyAll(); }
244                  return completion;
245              }
# Line 267 | Line 261 | public abstract class ForkJoinTask<V> im
261              } catch (Throwable rex) {
262                  return setExceptionalCompletion(rex);
263              }
264 <            while ((s = status) >= 0 && completed) {
265 <                if (U.compareAndSwapInt(this, STATUS, s, (s & ~SIGNAL)|NORMAL)) {
272 <                    if ((s & SIGNAL) != 0)
273 <                        synchronized (this) { notifyAll(); }
274 <                    return NORMAL;
275 <                }
276 <            }
264 >            if (completed)
265 >                s = setCompletion(NORMAL);
266          }
267          return s;
268      }
269  
270      /**
271 +     * Tries to set SIGNAL status unless already completed. Used by
272 +     * ForkJoinPool. Other variants are directly incorporated into
273 +     * externalAwaitDone etc.
274 +     *
275 +     * @return true if successful
276 +     */
277 +    final boolean trySetSignal() {
278 +        int s = status;
279 +        return s >= 0 && U.compareAndSwapInt(this, STATUS, s, s | SIGNAL);
280 +    }
281 +
282 +    /**
283       * Blocks a non-worker-thread until completion.
284       * @return status upon completion
285       */
286      private int externalAwaitDone() {
287          int s;
288 <        if ((s = status) >= 0) {
289 <            boolean interrupted = false;
290 <            synchronized (this) {
291 <                while ((s = status) >= 0) {
292 <                    if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
288 >        boolean interrupted = false;
289 >        if ((s = status) >= 0 && ForkJoinPool.tryUnsubmitFromCommonPool(this))
290 >            s = doExec();
291 >        while (s >= 0) {
292 >            if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
293 >                synchronized (this) {
294 >                    if (status >= 0) {
295                          try {
296                              wait();
297                          } catch (InterruptedException ie) {
298                              interrupted = true;
299                          }
300                      }
301 +                    else
302 +                        notifyAll();
303                  }
304              }
305 <            if (interrupted)
301 <                Thread.currentThread().interrupt();
305 >            s = status;
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)
310 <        throws InterruptedException {
311 <        int s;
315 >    private int externalInterruptibleAwaitDone() throws InterruptedException {
316          if (Thread.interrupted())
317              throw new InterruptedException();
318 <        if ((s = status) >= 0) {
319 <            synchronized (this) {
320 <                while ((s = status) >= 0) {
321 <                    if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
322 <                        wait(millis);
323 <                        if (millis > 0L)
324 <                            break;
325 <                    }
318 >        int s;
319 >        if ((s = status) >= 0 && ForkJoinPool.tryUnsubmitFromCommonPool(this))
320 >            s = doExec();
321 >        while (s >= 0) {
322 >            if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
323 >                synchronized (this) {
324 >                    if (status >= 0)
325 >                        wait();
326 >                    else
327 >                        notifyAll();
328                  }
329              }
330 +            s = status;
331          }
332          return s;
333      }
334  
328
335      /**
336       * Implementation for join, get, quietlyJoin. Directly handles
337       * only cases of already-completed, external wait, and
338 <     * unfork+exec.  Others are relayed to awaitJoin.
338 >     * unfork+exec.  Others are relayed to ForkJoinPool.awaitJoin.
339       *
340       * @return status upon completion
341       */
342      private int doJoin() {
343          int s; Thread t; ForkJoinWorkerThread wt; ForkJoinPool.WorkQueue w;
344 <        if ((s = status) >= 0) {
345 <            if (!((t = Thread.currentThread()) instanceof ForkJoinWorkerThread))
346 <                s = externalAwaitDone();
347 <            else if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue).
348 <                     tryUnpush(this) || (s = doExec()) >= 0)
349 <                s = awaitJoin(w, wt.pool);
344 <        }
345 <        return s;
346 <    }
347 <
348 <    /**
349 <     * Helps and/or blocks until joined.
350 <     *
351 <     * @param w the joiner
352 <     * @param p the pool
353 <     * @return status upon completion
354 <     */
355 <    private int awaitJoin(ForkJoinPool.WorkQueue w, ForkJoinPool p) {
356 <        int s;
357 <        ForkJoinTask<?> prevJoin = w.currentJoin;
358 <        w.currentJoin = this;
359 <        for (int k = HELP_RETRIES; (s = status) >= 0;) {
360 <            if ((w.queueSize() > 0) ?
361 <                w.tryRemoveAndExec(this) :        // self-help
362 <                p.tryHelpStealer(w, this))        // help process tasks
363 <                k = HELP_RETRIES;                 // reset if made progress
364 <            else if ((s = status) < 0)            // recheck
365 <                break;
366 <            else if (--k > 0) {
367 <                if ((k & 3) == 1)
368 <                    Thread.yield();               // occasionally yield
369 <            }
370 <            else if (k == 0)
371 <                p.tryPollForAndExec(w, this);     // uncommon self-help case
372 <            else if (p.tryCompensate()) {         // true if can block
373 <                try {
374 <                    int ss = status;
375 <                    if (ss >= 0 &&                // assert need signal
376 <                        U.compareAndSwapInt(this, STATUS, ss, ss | SIGNAL)) {
377 <                        synchronized (this) {
378 <                            if (status >= 0)      // block
379 <                                wait();
380 <                        }
381 <                    }
382 <                } catch (InterruptedException ignore) {
383 <                } finally {
384 <                    p.incrementActiveCount();     // re-activate
385 <                }
386 <            }
387 <        }
388 <        w.currentJoin = prevJoin;
389 <        return s;
344 >        return (s = status) < 0 ? s :
345 >            ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
346 >            (w = (wt = (ForkJoinWorkerThread)t).workQueue).
347 >            tryUnpush(this) && (s = doExec()) < 0 ? s :
348 >            wt.pool.awaitJoin(w, this) :
349 >            externalAwaitDone();
350      }
351  
352      /**
# Line 395 | Line 355 | public abstract class ForkJoinTask<V> im
355       * @return status upon completion
356       */
357      private int doInvoke() {
358 <        int s; Thread t;
359 <        if ((s = doExec()) >= 0) {
360 <            if (!((t = Thread.currentThread()) instanceof ForkJoinWorkerThread))
361 <                s = externalAwaitDone();
362 <            else {
403 <                ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
404 <                s = awaitJoin(wt.workQueue, wt.pool);
405 <            }
406 <        }
407 <        return s;
358 >        int s; Thread t; ForkJoinWorkerThread wt;
359 >        return (s = doExec()) < 0 ? s :
360 >            ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
361 >            (wt = (ForkJoinWorkerThread)t).pool.awaitJoin(wt.workQueue, this) :
362 >            externalAwaitDone();
363      }
364  
365      // Exception table support
# Line 439 | Line 394 | public abstract class ForkJoinTask<V> im
394       * any ForkJoinPool will call helpExpungeStaleExceptions when its
395       * pool becomes isQuiescent.
396       */
397 <    static final class ExceptionNode extends WeakReference<ForkJoinTask<?>>{
397 >    static final class ExceptionNode extends WeakReference<ForkJoinTask<?>> {
398          final Throwable ex;
399          ExceptionNode next;
400          final long thrower;  // use id not ref to avoid weak cycles
# Line 452 | Line 407 | public abstract class ForkJoinTask<V> im
407      }
408  
409      /**
410 <     * Records exception and sets exceptional completion.
410 >     * Records exception and sets status.
411       *
412       * @return status on exit
413       */
414 <    private int setExceptionalCompletion(Throwable ex) {
415 <        int h = System.identityHashCode(this);
416 <        final ReentrantLock lock = exceptionTableLock;
417 <        lock.lock();
418 <        try {
419 <            expungeStaleExceptions();
420 <            ExceptionNode[] t = exceptionTable;
421 <            int i = h & (t.length - 1);
422 <            for (ExceptionNode e = t[i]; ; e = e.next) {
423 <                if (e == null) {
424 <                    t[i] = new ExceptionNode(this, ex, t[i]);
425 <                    break;
414 >    final int recordExceptionalCompletion(Throwable ex) {
415 >        int s;
416 >        if ((s = status) >= 0) {
417 >            int h = System.identityHashCode(this);
418 >            final ReentrantLock lock = exceptionTableLock;
419 >            lock.lock();
420 >            try {
421 >                expungeStaleExceptions();
422 >                ExceptionNode[] t = exceptionTable;
423 >                int i = h & (t.length - 1);
424 >                for (ExceptionNode e = t[i]; ; e = e.next) {
425 >                    if (e == null) {
426 >                        t[i] = new ExceptionNode(this, ex, t[i]);
427 >                        break;
428 >                    }
429 >                    if (e.get() == this) // already present
430 >                        break;
431                  }
432 <                if (e.get() == this) // already present
433 <                    break;
432 >            } finally {
433 >                lock.unlock();
434              }
435 <        } finally {
476 <            lock.unlock();
435 >            s = setCompletion(EXCEPTIONAL);
436          }
437 <        return setCompletion(EXCEPTIONAL);
437 >        return s;
438 >    }
439 >
440 >    /**
441 >     * Records exception and possibly propagates
442 >     *
443 >     * @return status on exit
444 >     */
445 >    private int setExceptionalCompletion(Throwable ex) {
446 >        int s = recordExceptionalCompletion(ex);
447 >        if ((s & DONE_MASK) == EXCEPTIONAL)
448 >            internalPropagateException(ex);
449 >        return s;
450 >    }
451 >
452 >    /**
453 >     * Hook for exception propagation support for tasks with completers.
454 >     */
455 >    void internalPropagateException(Throwable ex) {
456      }
457  
458      /**
# Line 539 | Line 516 | public abstract class ForkJoinTask<V> im
516       * @return the exception, or null if none
517       */
518      private Throwable getThrowableException() {
519 <        if (status != EXCEPTIONAL)
519 >        if ((status & DONE_MASK) != EXCEPTIONAL)
520              return null;
521          int h = System.identityHashCode(this);
522          ExceptionNode e;
# Line 557 | Line 534 | public abstract class ForkJoinTask<V> im
534          Throwable ex;
535          if (e == null || (ex = e.ex) == null)
536              return null;
537 <        if (e.thrower != Thread.currentThread().getId()) {
537 >        if (false && e.thrower != Thread.currentThread().getId()) {
538              Class<? extends Throwable> ec = ex.getClass();
539              try {
540                  Constructor<?> noArgCtor = null;
# Line 624 | Line 601 | public abstract class ForkJoinTask<V> im
601      }
602  
603      /**
604 <     * Report the result of invoke or join; called only upon
605 <     * non-normal return of internal versions.
604 >     * A version of "sneaky throw" to relay exceptions
605 >     */
606 >    static void rethrow(final Throwable ex) {
607 >        if (ex != null) {
608 >            if (ex instanceof Error)
609 >                throw (Error)ex;
610 >            if (ex instanceof RuntimeException)
611 >                throw (RuntimeException)ex;
612 >            throw uncheckedThrowable(ex, RuntimeException.class);
613 >        }
614 >    }
615 >
616 >    /**
617 >     * The sneaky part of sneaky throw, relying on generics
618 >     * limitations to evade compiler complaints about rethrowing
619 >     * unchecked exceptions
620 >     */
621 >    @SuppressWarnings("unchecked") static <T extends Throwable>
622 >        T uncheckedThrowable(final Throwable t, final Class<T> c) {
623 >        return (T)t; // rely on vacuous cast
624 >    }
625 >
626 >    /**
627 >     * Throws exception, if any, associated with the given status.
628       */
629 <    private V reportResult() {
630 <        int s; Throwable ex;
632 <        if ((s = status) == CANCELLED)
629 >    private void reportException(int s) {
630 >        if (s == CANCELLED)
631              throw new CancellationException();
632 <        if (s == EXCEPTIONAL && (ex = getThrowableException()) != null)
633 <            U.throwException(ex);
636 <        return getRawResult();
632 >        if (s == EXCEPTIONAL)
633 >            rethrow(getThrowableException());
634      }
635  
636      // public methods
637  
638      /**
639 <     * Arranges to asynchronously execute this task.  While it is not
640 <     * necessarily enforced, it is a usage error to fork a task more
641 <     * than once unless it has completed and been reinitialized.
642 <     * Subsequent modifications to the state of this task or any data
643 <     * it operates on are not necessarily consistently observable by
644 <     * any thread other than the one executing it unless preceded by a
645 <     * call to {@link #join} or related methods, or a call to {@link
646 <     * #isDone} returning {@code true}.
647 <     *
648 <     * <p>This method may be invoked only from within {@code
649 <     * ForkJoinPool} computations (as may be determined using method
653 <     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
654 <     * result in exceptions or errors, possibly including {@code
655 <     * ClassCastException}.
639 >     * Arranges to asynchronously execute this task in the pool the
640 >     * current task is running in, if applicable, or using the {@link
641 >     * ForkJoinPool#commonPool} if not {@link #inForkJoinPool}.  While
642 >     * it is not necessarily enforced, it is a usage error to fork a
643 >     * task more than once unless it has completed and been
644 >     * reinitialized.  Subsequent modifications to the state of this
645 >     * task or any data it operates on are not necessarily
646 >     * consistently observable by any thread other than the one
647 >     * executing it unless preceded by a call to {@link #join} or
648 >     * related methods, or a call to {@link #isDone} returning {@code
649 >     * true}.
650       *
651       * @return {@code this}, to simplify usage
652       */
653      public final ForkJoinTask<V> fork() {
654 <        ForkJoinWorkerThread wt;
655 <        (wt = (ForkJoinWorkerThread)Thread.currentThread()).
656 <            workQueue.push(this, wt.pool);
654 >        Thread t;
655 >        if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)
656 >            ((ForkJoinWorkerThread)t).workQueue.push(this);
657 >        else
658 >            ForkJoinPool.submitToCommonPool(this);
659          return this;
660      }
661  
# Line 675 | Line 671 | public abstract class ForkJoinTask<V> im
671       * @return the computed result
672       */
673      public final V join() {
674 <        if (doJoin() != NORMAL)
675 <            return reportResult();
676 <        else
677 <            return getRawResult();
674 >        int s;
675 >        if ((s = doJoin() & DONE_MASK) != NORMAL)
676 >            reportException(s);
677 >        return getRawResult();
678      }
679  
680      /**
# Line 690 | Line 686 | public abstract class ForkJoinTask<V> im
686       * @return the computed result
687       */
688      public final V invoke() {
689 <        if (doInvoke() != NORMAL)
690 <            return reportResult();
691 <        else
692 <            return getRawResult();
689 >        int s;
690 >        if ((s = doInvoke() & DONE_MASK) != NORMAL)
691 >            reportException(s);
692 >        return getRawResult();
693      }
694  
695      /**
# Line 709 | Line 705 | public abstract class ForkJoinTask<V> im
705       * cancelled, completed normally or exceptionally, or left
706       * unprocessed.
707       *
712     * <p>This method may be invoked only from within {@code
713     * ForkJoinPool} computations (as may be determined using method
714     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
715     * result in exceptions or errors, possibly including {@code
716     * ClassCastException}.
717     *
708       * @param t1 the first task
709       * @param t2 the second task
710       * @throws NullPointerException if any task is null
711       */
712      public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) {
713 +        int s1, s2;
714          t2.fork();
715 <        t1.invoke();
716 <        t2.join();
715 >        if ((s1 = t1.doInvoke() & DONE_MASK) != NORMAL)
716 >            t1.reportException(s1);
717 >        if ((s2 = t2.doJoin() & DONE_MASK) != NORMAL)
718 >            t2.reportException(s2);
719      }
720  
721      /**
# Line 737 | Line 730 | public abstract class ForkJoinTask<V> im
730       * related methods to check if they have been cancelled, completed
731       * normally or exceptionally, or left unprocessed.
732       *
740     * <p>This method may be invoked only from within {@code
741     * ForkJoinPool} computations (as may be determined using method
742     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
743     * result in exceptions or errors, possibly including {@code
744     * ClassCastException}.
745     *
733       * @param tasks the tasks
734       * @throws NullPointerException if any task is null
735       */
# Line 770 | Line 757 | public abstract class ForkJoinTask<V> im
757              }
758          }
759          if (ex != null)
760 <            U.throwException(ex);
760 >            rethrow(ex);
761      }
762  
763      /**
# Line 786 | Line 773 | public abstract class ForkJoinTask<V> im
773       * cancelled, completed normally or exceptionally, or left
774       * unprocessed.
775       *
789     * <p>This method may be invoked only from within {@code
790     * ForkJoinPool} computations (as may be determined using method
791     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
792     * result in exceptions or errors, possibly including {@code
793     * ClassCastException}.
794     *
776       * @param tasks the collection of tasks
777       * @return the tasks argument, to simplify usage
778       * @throws NullPointerException if tasks or any element are null
# Line 827 | Line 808 | public abstract class ForkJoinTask<V> im
808              }
809          }
810          if (ex != null)
811 <            U.throwException(ex);
811 >            rethrow(ex);
812          return tasks;
813      }
814  
# Line 859 | Line 840 | public abstract class ForkJoinTask<V> im
840       * @return {@code true} if this task is now cancelled
841       */
842      public boolean cancel(boolean mayInterruptIfRunning) {
843 <        return setCompletion(CANCELLED) == CANCELLED;
843 >        return (setCompletion(CANCELLED) & DONE_MASK) == CANCELLED;
844      }
845  
846      public final boolean isDone() {
# Line 867 | Line 848 | public abstract class ForkJoinTask<V> im
848      }
849  
850      public final boolean isCancelled() {
851 <        return status == CANCELLED;
851 >        return (status & DONE_MASK) == CANCELLED;
852      }
853  
854      /**
# Line 887 | Line 868 | public abstract class ForkJoinTask<V> im
868       * exception and was not cancelled
869       */
870      public final boolean isCompletedNormally() {
871 <        return status == NORMAL;
871 >        return (status & DONE_MASK) == NORMAL;
872      }
873  
874      /**
# Line 898 | Line 879 | public abstract class ForkJoinTask<V> im
879       * @return the exception, or {@code null} if none
880       */
881      public final Throwable getException() {
882 <        int s = status;
882 >        int s = status & DONE_MASK;
883          return ((s >= NORMAL)    ? null :
884                  (s == CANCELLED) ? new CancellationException() :
885                  getThrowableException());
# Line 948 | Line 929 | public abstract class ForkJoinTask<V> im
929      }
930  
931      /**
932 +     * Completes this task normally without setting a value. The most
933 +     * recent value established by {@link #setRawResult} (or {@code
934 +     * null} by default) will be returned as the result of subsequent
935 +     * invocations of {@code join} and related operations.
936 +     *
937 +     * @since 1.8
938 +     */
939 +    public final void quietlyComplete() {
940 +        setCompletion(NORMAL);
941 +    }
942 +
943 +    /**
944       * Waits if necessary for the computation to complete, and then
945       * retrieves its result.
946       *
# Line 960 | Line 953 | public abstract class ForkJoinTask<V> im
953       */
954      public final V get() throws InterruptedException, ExecutionException {
955          int s = (Thread.currentThread() instanceof ForkJoinWorkerThread) ?
956 <            doJoin() : externalInterruptibleAwaitDone(0L);
956 >            doJoin() : externalInterruptibleAwaitDone();
957          Throwable ex;
958 <        if (s == CANCELLED)
958 >        if ((s &= DONE_MASK) == CANCELLED)
959              throw new CancellationException();
960          if (s == EXCEPTIONAL && (ex = getThrowableException()) != null)
961              throw new ExecutionException(ex);
# Line 985 | Line 978 | public abstract class ForkJoinTask<V> im
978       */
979      public final V get(long timeout, TimeUnit unit)
980          throws InterruptedException, ExecutionException, TimeoutException {
981 <        // Messy in part because we measure in nanos, but wait in millis
982 <        int s; long millis, nanos;
983 <        Thread t = Thread.currentThread();
984 <        if (!(t instanceof ForkJoinWorkerThread)) {
985 <            if ((millis = unit.toMillis(timeout)) > 0L)
986 <                s = externalInterruptibleAwaitDone(millis);
987 <            else
988 <                s = status;
989 <        }
990 <        else if ((s = status) >= 0 && (nanos = unit.toNanos(timeout)) > 0L) {
991 <            long deadline = System.nanoTime() + nanos;
992 <            ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
993 <            ForkJoinPool.WorkQueue w = wt.workQueue;
994 <            ForkJoinPool p = wt.pool;
995 <            if (w.tryUnpush(this))
996 <                doExec();
997 <            boolean blocking = false;
981 >        if (Thread.interrupted())
982 >            throw new InterruptedException();
983 >        // Messy in part because we measure in nanosecs, but wait in millisecs
984 >        int s; long ns, ms;
985 >        if ((s = status) >= 0 && (ns = unit.toNanos(timeout)) > 0L) {
986 >            long deadline = System.nanoTime() + ns;
987 >            ForkJoinPool p = null;
988 >            ForkJoinPool.WorkQueue w = null;
989 >            Thread t = Thread.currentThread();
990 >            if (t instanceof ForkJoinWorkerThread) {
991 >                ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
992 >                p = wt.pool;
993 >                w = wt.workQueue;
994 >                s = p.helpJoinOnce(w, this); // no retries on failure
995 >            }
996 >            boolean canBlock = false;
997 >            boolean interrupted = false;
998              try {
999                  while ((s = status) >= 0) {
1000 <                    if (w.runState < 0)
1000 >                    if (w != null && w.runState < 0)
1001                          cancelIgnoringExceptions(this);
1002 <                    else if (!blocking)
1003 <                        blocking = p.tryCompensate();
1002 >                    else if (!canBlock) {
1003 >                        if (p == null || p.tryCompensate(this, null))
1004 >                            canBlock = true;
1005 >                    }
1006                      else {
1007 <                        millis = TimeUnit.NANOSECONDS.toMillis(nanos);
1013 <                        if (millis > 0L &&
1007 >                        if ((ms = TimeUnit.NANOSECONDS.toMillis(ns)) > 0L &&
1008                              U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
1009 <                            try {
1010 <                                synchronized (this) {
1011 <                                    if (status >= 0)
1012 <                                        wait(millis);
1009 >                            synchronized (this) {
1010 >                                if (status >= 0) {
1011 >                                    try {
1012 >                                        wait(ms);
1013 >                                    } catch (InterruptedException ie) {
1014 >                                        if (p == null)
1015 >                                            interrupted = true;
1016 >                                    }
1017                                  }
1018 <                            } catch (InterruptedException ie) {
1018 >                                else
1019 >                                    notifyAll();
1020                              }
1021                          }
1022 <                        if ((s = status) < 0 ||
1023 <                            (nanos = deadline - System.nanoTime()) <= 0L)
1022 >                        if ((s = status) < 0 || interrupted ||
1023 >                            (ns = deadline - System.nanoTime()) <= 0L)
1024                              break;
1025                      }
1026                  }
1027              } finally {
1028 <                if (blocking)
1028 >                if (p != null && canBlock)
1029                      p.incrementActiveCount();
1030              }
1031 +            if (interrupted)
1032 +                throw new InterruptedException();
1033          }
1034 <        if (s != NORMAL) {
1034 >        if ((s &= DONE_MASK) != NORMAL) {
1035              Throwable ex;
1036              if (s == CANCELLED)
1037                  throw new CancellationException();
# Line 1067 | Line 1068 | public abstract class ForkJoinTask<V> im
1068       * be of use in designs in which many tasks are forked, but none
1069       * are explicitly joined, instead executing them until all are
1070       * processed.
1070     *
1071     * <p>This method may be invoked only from within {@code
1072     * ForkJoinPool} computations (as may be determined using method
1073     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
1074     * result in exceptions or errors, possibly including {@code
1075     * ClassCastException}.
1071       */
1072      public static void helpQuiesce() {
1073 <        ForkJoinWorkerThread wt =
1074 <            (ForkJoinWorkerThread)Thread.currentThread();
1075 <        wt.pool.helpQuiescePool(wt.workQueue);
1073 >        Thread t;
1074 >        if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) {
1075 >            ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
1076 >            wt.pool.helpQuiescePool(wt.workQueue);
1077 >        }
1078 >        else
1079 >            ForkJoinPool.externalHelpQuiescePool();
1080      }
1081  
1082      /**
# Line 1097 | Line 1096 | public abstract class ForkJoinTask<V> im
1096       * setRawResult(null)}.
1097       */
1098      public void reinitialize() {
1099 <        if (status == EXCEPTIONAL)
1099 >        if ((status & DONE_MASK) == EXCEPTIONAL)
1100              clearExceptionalCompletion();
1101          else
1102              status = 0;
# Line 1130 | Line 1129 | public abstract class ForkJoinTask<V> im
1129  
1130      /**
1131       * Tries to unschedule this task for execution. This method will
1132 <     * typically succeed if this task is the most recently forked task
1133 <     * by the current thread, and has not commenced executing in
1134 <     * another thread.  This method may be useful when arranging
1135 <     * alternative local processing of tasks that could have been, but
1136 <     * were not, stolen.
1138 <     *
1139 <     * <p>This method may be invoked only from within {@code
1140 <     * ForkJoinPool} computations (as may be determined using method
1141 <     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
1142 <     * result in exceptions or errors, possibly including {@code
1143 <     * ClassCastException}.
1132 >     * typically (but is not guaranteed to) succeed if this task is
1133 >     * the most recently forked task by the current thread, and has
1134 >     * not commenced executing in another thread.  This method may be
1135 >     * useful when arranging alternative local processing of tasks
1136 >     * that could have been, but were not, stolen.
1137       *
1138       * @return {@code true} if unforked
1139       */
1140      public boolean tryUnfork() {
1141 <        return ((ForkJoinWorkerThread)Thread.currentThread())
1142 <            .workQueue.tryUnpush(this);
1141 >        Thread t;
1142 >        return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
1143 >            ((ForkJoinWorkerThread)t).workQueue.tryUnpush(this) :
1144 >            ForkJoinPool.tryUnsubmitFromCommonPool(this);
1145      }
1146  
1147      /**
# Line 1155 | Line 1150 | public abstract class ForkJoinTask<V> im
1150       * value may be useful for heuristic decisions about whether to
1151       * fork other tasks.
1152       *
1158     * <p>This method may be invoked only from within {@code
1159     * ForkJoinPool} computations (as may be determined using method
1160     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
1161     * result in exceptions or errors, possibly including {@code
1162     * ClassCastException}.
1163     *
1153       * @return the number of tasks
1154       */
1155      public static int getQueuedTaskCount() {
1156 <        return ((ForkJoinWorkerThread) Thread.currentThread())
1157 <            .workQueue.queueSize();
1156 >        Thread t;
1157 >        return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
1158 >            ((ForkJoinWorkerThread)t).workQueue.queueSize() :
1159 >            ForkJoinPool.getEstimatedSubmitterQueueLength();
1160      }
1161  
1162      /**
1163       * Returns an estimate of how many more locally queued tasks are
1164       * held by the current worker thread than there are other worker
1165 <     * threads that might steal them.  This value may be useful for
1165 >     * threads that might steal them, or zero if this thread is not
1166 >     * operating in a ForkJoinPool. This value may be useful for
1167       * heuristic decisions about whether to fork other tasks. In many
1168       * usages of ForkJoinTasks, at steady state, each worker should
1169       * aim to maintain a small constant surplus (for example, 3) of
1170       * tasks, and to process computations locally if this threshold is
1171       * exceeded.
1172       *
1181     * <p>This method may be invoked only from within {@code
1182     * ForkJoinPool} computations (as may be determined using method
1183     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
1184     * result in exceptions or errors, possibly including {@code
1185     * ClassCastException}.
1186     *
1173       * @return the surplus number of tasks, which may be negative
1174       */
1175      public static int getSurplusQueuedTaskCount() {
# Line 1230 | Line 1216 | public abstract class ForkJoinTask<V> im
1216           * have zero queued tasks, so compensate by a factor of
1217           * (#idle/#active) threads.
1218           */
1219 <        ForkJoinWorkerThread wt =
1220 <            (ForkJoinWorkerThread)Thread.currentThread();
1221 <        return wt.workQueue.queueSize() - wt.pool.idlePerActive();
1219 >        Thread t; ForkJoinWorkerThread wt;
1220 >        return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
1221 >            (wt = (ForkJoinWorkerThread)t).workQueue.queueSize() - wt.pool.idlePerActive() :
1222 >            0;
1223      }
1224  
1225      // Extension methods
# Line 1258 | Line 1245 | public abstract class ForkJoinTask<V> im
1245      protected abstract void setRawResult(V value);
1246  
1247      /**
1248 <     * Immediately performs the base action of this task.  This method
1249 <     * is designed to support extensions, and should not in general be
1250 <     * called otherwise. The return value controls whether this task
1251 <     * is considered to be done normally. It may return false in
1248 >     * Immediately performs the base action of this task and returns
1249 >     * true if, upon return from this method, this task is guaranteed
1250 >     * to have completed normally. This method may return false
1251 >     * otherwise, to indicate that this task is not necessarily
1252 >     * complete (or is not known to be complete), for example in
1253       * asynchronous actions that require explicit invocations of
1254 <     * {@link #complete} to become joinable. It may also throw an
1255 <     * (unchecked) exception to indicate abnormal exit.
1254 >     * completion methods. This method may also throw an (unchecked)
1255 >     * exception to indicate abnormal exit. This method is designed to
1256 >     * support extensions, and should not in general be called
1257 >     * otherwise.
1258       *
1259 <     * @return {@code true} if completed normally
1259 >     * @return {@code true} if this task is known to have completed normally
1260       */
1261      protected abstract boolean exec();
1262  
1263      /**
1264       * Returns, but does not unschedule or execute, a task queued by
1265       * the current thread but not yet executed, if one is immediately
1266 <     * available. There is no guarantee that this task will actually
1267 <     * be polled or executed next. Conversely, this method may return
1268 <     * null even if a task exists but cannot be accessed without
1269 <     * contention with other threads.  This method is designed
1266 >     * available and the current thread is operating in a
1267 >     * ForkJoinPool. There is no guarantee that this task will
1268 >     * actually be polled or executed next. Conversely, this method
1269 >     * may return null even if a task exists but cannot be accessed
1270 >     * without contention with other threads.  This method is designed
1271       * primarily to support extensions, and is unlikely to be useful
1272       * otherwise.
1273       *
1283     * <p>This method may be invoked only from within {@code
1284     * ForkJoinPool} computations (as may be determined using method
1285     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
1286     * result in exceptions or errors, possibly including {@code
1287     * ClassCastException}.
1288     *
1274       * @return the next task, or {@code null} if none are available
1275       */
1276      protected static ForkJoinTask<?> peekNextLocalTask() {
1277 <        return ((ForkJoinWorkerThread) Thread.currentThread()).workQueue.peek();
1277 >        Thread t;
1278 >        return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
1279 >            ((ForkJoinWorkerThread)t).workQueue.peek() :
1280 >            null;
1281      }
1282  
1283      /**
1284       * Unschedules and returns, without executing, the next task
1285 <     * queued by the current thread but not yet executed.  This method
1286 <     * is designed primarily to support extensions, and is unlikely to
1287 <     * be useful otherwise.
1288 <     *
1301 <     * <p>This method may be invoked only from within {@code
1302 <     * ForkJoinPool} computations (as may be determined using method
1303 <     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
1304 <     * result in exceptions or errors, possibly including {@code
1305 <     * ClassCastException}.
1285 >     * queued by the current thread but not yet executed, if the
1286 >     * current thread is operating in a ForkJoinPool.  This method is
1287 >     * designed primarily to support extensions, and is unlikely to be
1288 >     * useful otherwise.
1289       *
1290       * @return the next task, or {@code null} if none are available
1291       */
1292      protected static ForkJoinTask<?> pollNextLocalTask() {
1293 <        return ((ForkJoinWorkerThread) Thread.currentThread())
1294 <            .workQueue.nextLocalTask();
1293 >        Thread t;
1294 >        return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
1295 >            ((ForkJoinWorkerThread)t).workQueue.nextLocalTask() :
1296 >            null;
1297      }
1298  
1299      /**
1300 <     * Unschedules and returns, without executing, the next task
1300 >     * If the current thread is operating in a ForkJoinPool,
1301 >     * unschedules and returns, without executing, the next task
1302       * queued by the current thread but not yet executed, if one is
1303       * available, or if not available, a task that was forked by some
1304       * other thread, if available. Availability may be transient, so a
1305 <     * {@code null} result does not necessarily imply quiescence
1306 <     * of the pool this task is operating in.  This method is designed
1305 >     * {@code null} result does not necessarily imply quiescence of
1306 >     * the pool this task is operating in.  This method is designed
1307       * primarily to support extensions, and is unlikely to be useful
1308       * otherwise.
1309       *
1324     * <p>This method may be invoked only from within {@code
1325     * ForkJoinPool} computations (as may be determined using method
1326     * {@link #inForkJoinPool}).  Attempts to invoke in other contexts
1327     * result in exceptions or errors, possibly including {@code
1328     * ClassCastException}.
1329     *
1310       * @return a task, or {@code null} if none are available
1311       */
1312      protected static ForkJoinTask<?> pollTask() {
1313 <        ForkJoinWorkerThread wt =
1314 <            (ForkJoinWorkerThread)Thread.currentThread();
1315 <        return wt.pool.nextTaskFor(wt.workQueue);
1313 >        Thread t; ForkJoinWorkerThread wt;
1314 >        return ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
1315 >            (wt = (ForkJoinWorkerThread)t).pool.nextTaskFor(wt.workQueue) :
1316 >            null;
1317      }
1318  
1319 <    // Mark-bit operations
1319 >    // tag operations
1320  
1321      /**
1322 <     * Returns true if this task is marked.
1322 >     * Returns the tag for this task.
1323       *
1324 <     * @return true if this task is marked
1324 >     * @return the tag for this task
1325       * @since 1.8
1326       */
1327 <    public final boolean isMarkedForkJoinTask() {
1328 <        return (status & MARKED) != 0;
1327 >    public final short getForkJoinTaskTag() {
1328 >        return (short)status;
1329      }
1330  
1331      /**
1332 <     * Atomically sets the mark on this task.
1332 >     * Atomically sets the tag value for this task.
1333       *
1334 <     * @return true if this task was previously unmarked
1334 >     * @param tag the tag value
1335 >     * @return the previous value of the tag
1336       * @since 1.8
1337       */
1338 <    public final boolean markForkJoinTask() {
1338 >    public final short setForkJoinTaskTag(short tag) {
1339          for (int s;;) {
1340 <            if (((s = status) & MARKED) != 0)
1341 <                return false;
1342 <            if (U.compareAndSwapInt(this, STATUS, s, s | MARKED))
1361 <                return true;
1340 >            if (U.compareAndSwapInt(this, STATUS, s = status,
1341 >                                    (s & ~SMASK) | (tag & SMASK)))
1342 >                return (short)s;
1343          }
1344      }
1345  
1346      /**
1347 <     * Atomically clears the mark on this task.
1347 >     * Atomically conditionally sets the tag value for this task.
1348 >     * Among other applications, tags can be used as visit markers
1349 >     * in tasks operating on graphs, as in methods that check: {@code
1350 >     * if (task.compareAndSetForkJoinTaskTag((short)0, (short)1))}
1351 >     * before processing, otherwise exiting because the node has
1352 >     * already been visited.
1353       *
1354 <     * @return true if this task was previously marked
1354 >     * @param e the expected tag value
1355 >     * @param tag the new tag value
1356 >     * @return true if successful; i.e., the current value was
1357 >     * equal to e and is now tag.
1358       * @since 1.8
1359       */
1360 <    public final boolean unmarkForkJoinTask() {
1360 >    public final boolean compareAndSetForkJoinTaskTag(short e, short tag) {
1361          for (int s;;) {
1362 <            if (((s = status) & MARKED) == 0)
1362 >            if ((short)(s = status) != e)
1363                  return false;
1364 <            if (U.compareAndSwapInt(this, STATUS, s, s & ~MARKED))
1364 >            if (U.compareAndSwapInt(this, STATUS, s,
1365 >                                    (s & ~SMASK) | (tag & SMASK)))
1366                  return true;
1367          }
1368      }
# Line 1385 | Line 1375 | public abstract class ForkJoinTask<V> im
1375      static final class AdaptedRunnable<T> extends ForkJoinTask<T>
1376          implements RunnableFuture<T> {
1377          final Runnable runnable;
1388        final T resultOnCompletion;
1378          T result;
1379          AdaptedRunnable(Runnable runnable, T result) {
1380              if (runnable == null) throw new NullPointerException();
1381              this.runnable = runnable;
1382 <            this.resultOnCompletion = result;
1382 >            this.result = result; // OK to set this even before completion
1383          }
1384 <        public T getRawResult() { return result; }
1385 <        public void setRawResult(T v) { result = v; }
1386 <        public boolean exec() {
1387 <            runnable.run();
1388 <            result = resultOnCompletion;
1389 <            return true;
1384 >        public final T getRawResult() { return result; }
1385 >        public final void setRawResult(T v) { result = v; }
1386 >        public final boolean exec() { runnable.run(); return true; }
1387 >        public final void run() { invoke(); }
1388 >        private static final long serialVersionUID = 5232453952276885070L;
1389 >    }
1390 >
1391 >    /**
1392 >     * Adaptor for Runnables without results
1393 >     */
1394 >    static final class AdaptedRunnableAction extends ForkJoinTask<Void>
1395 >        implements RunnableFuture<Void> {
1396 >        final Runnable runnable;
1397 >        AdaptedRunnableAction(Runnable runnable) {
1398 >            if (runnable == null) throw new NullPointerException();
1399 >            this.runnable = runnable;
1400          }
1401 <        public void run() { invoke(); }
1401 >        public final Void getRawResult() { return null; }
1402 >        public final void setRawResult(Void v) { }
1403 >        public final boolean exec() { runnable.run(); return true; }
1404 >        public final void run() { invoke(); }
1405          private static final long serialVersionUID = 5232453952276885070L;
1406      }
1407  
# Line 1414 | Line 1416 | public abstract class ForkJoinTask<V> im
1416              if (callable == null) throw new NullPointerException();
1417              this.callable = callable;
1418          }
1419 <        public T getRawResult() { return result; }
1420 <        public void setRawResult(T v) { result = v; }
1421 <        public boolean exec() {
1419 >        public final T getRawResult() { return result; }
1420 >        public final void setRawResult(T v) { result = v; }
1421 >        public final boolean exec() {
1422              try {
1423                  result = callable.call();
1424                  return true;
# Line 1428 | Line 1430 | public abstract class ForkJoinTask<V> im
1430                  throw new RuntimeException(ex);
1431              }
1432          }
1433 <        public void run() { invoke(); }
1433 >        public final void run() { invoke(); }
1434          private static final long serialVersionUID = 2838392045355241008L;
1435      }
1436  
# Line 1441 | Line 1443 | public abstract class ForkJoinTask<V> im
1443       * @return the task
1444       */
1445      public static ForkJoinTask<?> adapt(Runnable runnable) {
1446 <        return new AdaptedRunnable<Void>(runnable, null);
1446 >        return new AdaptedRunnableAction(runnable);
1447      }
1448  
1449      /**

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