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root/jsr166/jsr166/src/jsr166y/ForkJoinPool.java
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Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.24 by dl, Sat Jul 25 17:49:01 2009 UTC vs.
Revision 1.39 by jsr166, Sun Aug 2 17:55:51 2009 UTC

# Line 20 | Line 20 | import java.util.concurrent.atomic.Atomi
20   import java.util.concurrent.atomic.AtomicLong;
21  
22   /**
23 < * An {@link ExecutorService} for running {@link ForkJoinTask}s.  A
24 < * ForkJoinPool provides the entry point for submissions from
25 < * non-ForkJoinTasks, as well as management and monitoring operations.
26 < * Normally a single ForkJoinPool is used for a large number of
27 < * submitted tasks. Otherwise, use would not usually outweigh the
28 < * construction and bookkeeping overhead of creating a large set of
29 < * threads.
23 > * An {@link ExecutorService} for running {@link ForkJoinTask}s.
24 > * A {@code ForkJoinPool} provides the entry point for submissions
25 > * from non-{@code ForkJoinTask}s, as well as management and
26 > * monitoring operations.  Normally a single {@code ForkJoinPool} is
27 > * used for a large number of submitted tasks. Otherwise, use would
28 > * not usually outweigh the construction and bookkeeping overhead of
29 > * creating a large set of threads.
30   *
31 < * <p>ForkJoinPools differ from other kinds of Executors mainly in
32 < * that they provide <em>work-stealing</em>: all threads in the pool
33 < * attempt to find and execute subtasks created by other active tasks
34 < * (eventually blocking if none exist). This makes them efficient when
35 < * most tasks spawn other subtasks (as do most ForkJoinTasks), as well
36 < * as the mixed execution of some plain Runnable- or Callable- based
37 < * activities along with ForkJoinTasks. When setting
38 < * {@code setAsyncMode}, a ForkJoinPools may also be appropriate for
39 < * use with fine-grained tasks that are never joined. Otherwise, other
40 < * ExecutorService implementations are typically more appropriate
41 < * choices.
31 > * <p>{@code ForkJoinPool}s differ from other kinds of {@link
32 > * Executor}s mainly in that they provide <em>work-stealing</em>: all
33 > * threads in the pool attempt to find and execute subtasks created by
34 > * other active tasks (eventually blocking if none exist). This makes
35 > * them efficient when most tasks spawn other subtasks (as do most
36 > * {@code ForkJoinTask}s), as well as the mixed execution of some
37 > * plain {@code Runnable}- or {@code Callable}- based activities along
38 > * with {@code ForkJoinTask}s. When setting {@linkplain #setAsyncMode
39 > * async mode}, a {@code ForkJoinPool} may also be appropriate for use
40 > * with fine-grained tasks that are never joined. Otherwise, other
41 > * {@code ExecutorService} implementations are typically more
42 > * appropriate choices.
43   *
44 < * <p>A ForkJoinPool may be constructed with a given parallelism level
45 < * (target pool size), which it attempts to maintain by dynamically
46 < * adding, suspending, or resuming threads, even if some tasks are
47 < * waiting to join others. However, no such adjustments are performed
48 < * in the face of blocked IO or other unmanaged synchronization. The
49 < * nested {@code ManagedBlocker} interface enables extension of
50 < * the kinds of synchronization accommodated.  The target parallelism
51 < * level may also be changed dynamically ({@code setParallelism})
52 < * and thread construction can be limited using methods
53 < * {@code setMaximumPoolSize} and/or
54 < * {@code setMaintainsParallelism}.
44 > * <p>A {@code ForkJoinPool} may be constructed with a given
45 > * parallelism level (target pool size), which it attempts to maintain
46 > * by dynamically adding, suspending, or resuming threads, even if
47 > * some tasks are waiting to join others. However, no such adjustments
48 > * are performed in the face of blocked IO or other unmanaged
49 > * synchronization. The nested {@link ManagedBlocker} interface
50 > * enables extension of the kinds of synchronization accommodated.
51 > * The target parallelism level may also be changed dynamically
52 > * ({@link #setParallelism}) and thread construction can be limited
53 > * using methods {@link #setMaximumPoolSize} and/or {@link
54 > * #setMaintainsParallelism}.
55   *
56   * <p>In addition to execution and lifecycle control methods, this
57   * class provides status check methods (for example
58 < * {@code getStealCount}) that are intended to aid in developing,
58 > * {@link #getStealCount}) that are intended to aid in developing,
59   * tuning, and monitoring fork/join applications. Also, method
60 < * {@code toString} returns indications of pool state in a
60 > * {@link #toString} returns indications of pool state in a
61   * convenient form for informal monitoring.
62   *
63   * <p><b>Implementation notes</b>: This implementation restricts the
64   * maximum number of running threads to 32767. Attempts to create
65   * pools with greater than the maximum result in
66 < * IllegalArgumentExceptions.
66 > * {@code IllegalArgumentException}.
67   *
68   * @since 1.7
69   * @author Doug Lea
# Line 81 | Line 82 | public class ForkJoinPool extends Abstra
82      private static final int MAX_THREADS =  0x7FFF;
83  
84      /**
85 <     * Factory for creating new ForkJoinWorkerThreads.  A
86 <     * ForkJoinWorkerThreadFactory must be defined and used for
87 <     * ForkJoinWorkerThread subclasses that extend base functionality
88 <     * or initialize threads with different contexts.
85 >     * Factory for creating new {@link ForkJoinWorkerThread}s.
86 >     * A {@code ForkJoinWorkerThreadFactory} must be defined and used
87 >     * for {@code ForkJoinWorkerThread} subclasses that extend base
88 >     * functionality or initialize threads with different contexts.
89       */
90      public static interface ForkJoinWorkerThreadFactory {
91          /**
# Line 311 | Line 312 | public class ForkJoinPool extends Abstra
312      }
313  
314      /**
315 <     * Returns true if argument represents zero active count and
316 <     * nonzero runstate, which is the triggering condition for
315 >     * Returns {@code true} if argument represents zero active count
316 >     * and nonzero runstate, which is the triggering condition for
317       * terminating on shutdown.
318       */
319      private static boolean canTerminateOnShutdown(int c) {
# Line 578 | Line 579 | public class ForkJoinPool extends Abstra
579       * @throws NullPointerException if task is null
580       * @throws RejectedExecutionException if pool is shut down
581       */
582 <    public <T> void execute(ForkJoinTask<T> task) {
582 >    public void execute(ForkJoinTask<?> task) {
583          doSubmit(task);
584      }
585  
# Line 586 | Line 587 | public class ForkJoinPool extends Abstra
587  
588      public void execute(Runnable task) {
589          ForkJoinTask<?> job;
590 <        if (task instanceof ForkJoinTask) // avoid re-wrap
591 <            job = (ForkJoinTask<?>)task;
590 >        if (task instanceof ForkJoinTask<?>) // avoid re-wrap
591 >            job = (ForkJoinTask<?>) task;
592          else
593 <            job = new AdaptedRunnable<Void>(task, null);
593 >            job = ForkJoinTask.adapt(task, null);
594          doSubmit(job);
595      }
596  
597      public <T> ForkJoinTask<T> submit(Callable<T> task) {
598 <        ForkJoinTask<T> job = new AdaptedCallable<T>(task);
598 >        ForkJoinTask<T> job = ForkJoinTask.adapt(task);
599          doSubmit(job);
600          return job;
601      }
602  
603      public <T> ForkJoinTask<T> submit(Runnable task, T result) {
604 <        ForkJoinTask<T> job = new AdaptedRunnable<T>(task, result);
604 >        ForkJoinTask<T> job = ForkJoinTask.adapt(task, result);
605          doSubmit(job);
606          return job;
607      }
608  
609      public ForkJoinTask<?> submit(Runnable task) {
610          ForkJoinTask<?> job;
611 <        if (task instanceof ForkJoinTask) // avoid re-wrap
612 <            job = (ForkJoinTask<?>)task;
611 >        if (task instanceof ForkJoinTask<?>) // avoid re-wrap
612 >            job = (ForkJoinTask<?>) task;
613          else
614 <            job = new AdaptedRunnable<Void>(task, null);
614 >            job = ForkJoinTask.adapt(task, null);
615          doSubmit(job);
616          return job;
617      }
# Line 629 | Line 630 | public class ForkJoinPool extends Abstra
630          return task;
631      }
632  
632    /**
633     * Adaptor for Runnables. This implements RunnableFuture
634     * to be compliant with AbstractExecutorService constraints.
635     */
636    static final class AdaptedRunnable<T> extends ForkJoinTask<T>
637        implements RunnableFuture<T> {
638        final Runnable runnable;
639        final T resultOnCompletion;
640        T result;
641        AdaptedRunnable(Runnable runnable, T result) {
642            if (runnable == null) throw new NullPointerException();
643            this.runnable = runnable;
644            this.resultOnCompletion = result;
645        }
646        public T getRawResult() { return result; }
647        public void setRawResult(T v) { result = v; }
648        public boolean exec() {
649            runnable.run();
650            result = resultOnCompletion;
651            return true;
652        }
653        public void run() { invoke(); }
654        private static final long serialVersionUID = 5232453952276885070L;
655    }
656
657    /**
658     * Adaptor for Callables
659     */
660    static final class AdaptedCallable<T> extends ForkJoinTask<T>
661        implements RunnableFuture<T> {
662        final Callable<T> callable;
663        T result;
664        AdaptedCallable(Callable<T> callable) {
665            if (callable == null) throw new NullPointerException();
666            this.callable = callable;
667        }
668        public T getRawResult() { return result; }
669        public void setRawResult(T v) { result = v; }
670        public boolean exec() {
671            try {
672                result = callable.call();
673                return true;
674            } catch (Error err) {
675                throw err;
676            } catch (RuntimeException rex) {
677                throw rex;
678            } catch (Exception ex) {
679                throw new RuntimeException(ex);
680            }
681        }
682        public void run() { invoke(); }
683        private static final long serialVersionUID = 2838392045355241008L;
684    }
633  
634      public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
635          ArrayList<ForkJoinTask<T>> forkJoinTasks =
636              new ArrayList<ForkJoinTask<T>>(tasks.size());
637          for (Callable<T> task : tasks)
638 <            forkJoinTasks.add(new AdaptedCallable<T>(task));
638 >            forkJoinTasks.add(ForkJoinTask.adapt(task));
639          invoke(new InvokeAll<T>(forkJoinTasks));
640  
641          @SuppressWarnings({"unchecked", "rawtypes"})
# Line 720 | Line 668 | public class ForkJoinPool extends Abstra
668       * Returns the handler for internal worker threads that terminate
669       * due to unrecoverable errors encountered while executing tasks.
670       *
671 <     * @return the handler, or null if none
671 >     * @return the handler, or {@code null} if none
672       */
673      public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
674          Thread.UncaughtExceptionHandler h;
# Line 741 | Line 689 | public class ForkJoinPool extends Abstra
689       * as handler.
690       *
691       * @param h the new handler
692 <     * @return the old handler, or null if none
692 >     * @return the old handler, or {@code null} if none
693       * @throws SecurityException if a security manager exists and
694       *         the caller is not permitted to modify threads
695       *         because it does not hold {@link
# Line 815 | Line 763 | public class ForkJoinPool extends Abstra
763      /**
764       * Returns the number of worker threads that have started but not
765       * yet terminated.  This result returned by this method may differ
766 <     * from {@code getParallelism} when threads are created to
766 >     * from {@link #getParallelism} when threads are created to
767       * maintain parallelism when others are cooperatively blocked.
768       *
769       * @return the number of worker threads
# Line 840 | Line 788 | public class ForkJoinPool extends Abstra
788       * Setting this value has no effect on current pool size. It
789       * controls construction of new threads.
790       *
791 <     * @throws IllegalArgumentException if negative or greater then
791 >     * @throws IllegalArgumentException if negative or greater than
792       * internal implementation limit
793       */
794      public void setMaximumPoolSize(int newMax) {
# Line 851 | Line 799 | public class ForkJoinPool extends Abstra
799  
800  
801      /**
802 <     * Returns true if this pool dynamically maintains its target
803 <     * parallelism level. If false, new threads are added only to
804 <     * avoid possible starvation.
857 <     * This setting is by default true.
802 >     * Returns {@code true} if this pool dynamically maintains its
803 >     * target parallelism level. If false, new threads are added only
804 >     * to avoid possible starvation.  This setting is by default true.
805       *
806 <     * @return true if maintains parallelism
806 >     * @return {@code true} if maintains parallelism
807       */
808      public boolean getMaintainsParallelism() {
809          return maintainsParallelism;
# Line 867 | Line 814 | public class ForkJoinPool extends Abstra
814       * parallelism level. If false, new threads are added only to
815       * avoid possible starvation.
816       *
817 <     * @param enable true to maintains parallelism
817 >     * @param enable {@code true} to maintain parallelism
818       */
819      public void setMaintainsParallelism(boolean enable) {
820          maintainsParallelism = enable;
# Line 878 | Line 825 | public class ForkJoinPool extends Abstra
825       * tasks that are never joined. This mode may be more appropriate
826       * than default locally stack-based mode in applications in which
827       * worker threads only process asynchronous tasks.  This method is
828 <     * designed to be invoked only when pool is quiescent, and
828 >     * designed to be invoked only when the pool is quiescent, and
829       * typically only before any tasks are submitted. The effects of
830       * invocations at other times may be unpredictable.
831       *
832 <     * @param async if true, use locally FIFO scheduling
832 >     * @param async if {@code true}, use locally FIFO scheduling
833       * @return the previous mode
834 +     * @see #getAsyncMode
835       */
836      public boolean setAsyncMode(boolean async) {
837          boolean oldMode = locallyFifo;
# Line 900 | Line 848 | public class ForkJoinPool extends Abstra
848      }
849  
850      /**
851 <     * Returns true if this pool uses local first-in-first-out
851 >     * Returns {@code true} if this pool uses local first-in-first-out
852       * scheduling mode for forked tasks that are never joined.
853       *
854 <     * @return true if this pool uses async mode
854 >     * @return {@code true} if this pool uses async mode
855 >     * @see #setAsyncMode
856       */
857      public boolean getAsyncMode() {
858          return locallyFifo;
# Line 944 | Line 893 | public class ForkJoinPool extends Abstra
893      }
894  
895      /**
896 <     * Returns true if all worker threads are currently idle. An idle
897 <     * worker is one that cannot obtain a task to execute because none
898 <     * are available to steal from other threads, and there are no
899 <     * pending submissions to the pool. This method is conservative;
900 <     * it might not return true immediately upon idleness of all
901 <     * threads, but will eventually become true if threads remain
902 <     * inactive.
896 >     * Returns {@code true} if all worker threads are currently idle.
897 >     * An idle worker is one that cannot obtain a task to execute
898 >     * because none are available to steal from other threads, and
899 >     * there are no pending submissions to the pool. This method is
900 >     * conservative; it might not return {@code true} immediately upon
901 >     * idleness of all threads, but will eventually become true if
902 >     * threads remain inactive.
903       *
904 <     * @return true if all threads are currently idle
904 >     * @return {@code true} if all threads are currently idle
905       */
906      public boolean isQuiescent() {
907          return activeCountOf(runControl) == 0;
# Line 1018 | Line 967 | public class ForkJoinPool extends Abstra
967      }
968  
969      /**
970 <     * Returns true if there are any tasks submitted to this pool
971 <     * that have not yet begun executing.
970 >     * Returns {@code true} if there are any tasks submitted to this
971 >     * pool that have not yet begun executing.
972       *
973       * @return {@code true} if there are any queued submissions
974       */
# Line 1032 | Line 981 | public class ForkJoinPool extends Abstra
981       * available.  This method may be useful in extensions to this
982       * class that re-assign work in systems with multiple pools.
983       *
984 <     * @return the next submission, or null if none
984 >     * @return the next submission, or {@code null} if none
985       */
986      protected ForkJoinTask<?> pollSubmission() {
987          return submissionQueue.poll();
# Line 1055 | Line 1004 | public class ForkJoinPool extends Abstra
1004       * @param c the collection to transfer elements into
1005       * @return the number of elements transferred
1006       */
1007 <    protected int drainTasksTo(Collection<ForkJoinTask<?>> c) {
1007 >    protected int drainTasksTo(Collection<? super ForkJoinTask<?>> c) {
1008          int n = submissionQueue.drainTo(c);
1009          ForkJoinWorkerThread[] ws = workers;
1010          if (ws != null) {
# Line 1121 | Line 1070 | public class ForkJoinPool extends Abstra
1070      public void shutdown() {
1071          checkPermission();
1072          transitionRunStateTo(SHUTDOWN);
1073 <        if (canTerminateOnShutdown(runControl))
1073 >        if (canTerminateOnShutdown(runControl)) {
1074 >            if (workers == null) { // shutting down before workers created
1075 >                final ReentrantLock lock = this.workerLock;
1076 >                lock.lock();
1077 >                try {
1078 >                    if (workers == null) {
1079 >                        terminate();
1080 >                        transitionRunStateTo(TERMINATED);
1081 >                        termination.signalAll();
1082 >                    }
1083 >                } finally {
1084 >                    lock.unlock();
1085 >                }
1086 >            }
1087              terminateOnShutdown();
1088 +        }
1089      }
1090  
1091      /**
# Line 1132 | Line 1095 | public class ForkJoinPool extends Abstra
1095       * method may or may not be rejected. Unlike some other executors,
1096       * this method cancels rather than collects non-executed tasks
1097       * upon termination, so always returns an empty list. However, you
1098 <     * can use method {@code drainTasksTo} before invoking this
1098 >     * can use method {@link #drainTasksTo} before invoking this
1099       * method to transfer unexecuted tasks to another collection.
1100       *
1101       * @return an empty list
# Line 1492 | Line 1455 | public class ForkJoinPool extends Abstra
1455      }
1456  
1457      /**
1458 <     * Returns true if worker waiting on sync can proceed:
1458 >     * Returns {@code true} if worker waiting on sync can proceed:
1459       *  - on signal (thread == null)
1460       *  - on event count advance (winning race to notify vs signaller)
1461       *  - on interrupt
# Line 1500 | Line 1463 | public class ForkJoinPool extends Abstra
1463       * If node was not signalled and event count not advanced on exit,
1464       * then we also help advance event count.
1465       *
1466 <     * @return true if node can be released
1466 >     * @return {@code true} if node can be released
1467       */
1468      final boolean syncIsReleasable(WaitQueueNode node) {
1469          long prev = node.count;
# Line 1519 | Line 1482 | public class ForkJoinPool extends Abstra
1482      }
1483  
1484      /**
1485 <     * Returns true if a new sync event occurred since last call to
1486 <     * sync or this method, if so, updating caller's count.
1485 >     * Returns {@code true} if a new sync event occurred since last
1486 >     * call to sync or this method, if so, updating caller's count.
1487       */
1488      final boolean hasNewSyncEvent(ForkJoinWorkerThread w) {
1489          long lc = w.lastEventCount;
# Line 1604 | Line 1567 | public class ForkJoinPool extends Abstra
1567      }
1568  
1569      /**
1570 <     * Returns true if a spare thread appears to be needed.  If
1571 <     * maintaining parallelism, returns true when the deficit in
1570 >     * Returns {@code true} if a spare thread appears to be needed.
1571 >     * If maintaining parallelism, returns true when the deficit in
1572       * running threads is more than the surplus of total threads, and
1573       * there is apparently some work to do.  This self-limiting rule
1574       * means that the more threads that have already been added, the
# Line 1773 | Line 1736 | public class ForkJoinPool extends Abstra
1736  
1737      /**
1738       * Interface for extending managed parallelism for tasks running
1739 <     * in ForkJoinPools. A ManagedBlocker provides two methods.
1740 <     * Method {@code isReleasable} must return true if blocking is not
1741 <     * necessary. Method {@code block} blocks the current thread if
1742 <     * necessary (perhaps internally invoking {@code isReleasable}
1743 <     * before actually blocking.).
1739 >     * in {@link ForkJoinPool}s.
1740 >     *
1741 >     * <p>A {@code ManagedBlocker} provides two methods.
1742 >     * Method {@code isReleasable} must return {@code true} if
1743 >     * blocking is not necessary. Method {@code block} blocks the
1744 >     * current thread if necessary (perhaps internally invoking
1745 >     * {@code isReleasable} before actually blocking.).
1746       *
1747       * <p>For example, here is a ManagedBlocker based on a
1748       * ReentrantLock:
# Line 1801 | Line 1766 | public class ForkJoinPool extends Abstra
1766           * Possibly blocks the current thread, for example waiting for
1767           * a lock or condition.
1768           *
1769 <         * @return true if no additional blocking is necessary (i.e.,
1770 <         * if isReleasable would return true)
1769 >         * @return {@code true} if no additional blocking is necessary
1770 >         * (i.e., if isReleasable would return true)
1771           * @throws InterruptedException if interrupted while waiting
1772           * (the method is not required to do so, but is allowed to)
1773           */
1774          boolean block() throws InterruptedException;
1775  
1776          /**
1777 <         * Returns true if blocking is unnecessary.
1777 >         * Returns {@code true} if blocking is unnecessary.
1778           */
1779          boolean isReleasable();
1780      }
1781  
1782      /**
1783       * Blocks in accord with the given blocker.  If the current thread
1784 <     * is a ForkJoinWorkerThread, this method possibly arranges for a
1785 <     * spare thread to be activated if necessary to ensure parallelism
1786 <     * while the current thread is blocked.  If
1787 <     * {@code maintainParallelism} is true and the pool supports
1788 <     * it ({@link #getMaintainsParallelism}), this method attempts to
1789 <     * maintain the pool's nominal parallelism. Otherwise it activates
1790 <     * a thread only if necessary to avoid complete starvation. This
1791 <     * option may be preferable when blockages use timeouts, or are
1792 <     * almost always brief.
1784 >     * is a {@link ForkJoinWorkerThread}, this method possibly
1785 >     * arranges for a spare thread to be activated if necessary to
1786 >     * ensure parallelism while the current thread is blocked.
1787 >     *
1788 >     * <p>If {@code maintainParallelism} is {@code true} and the pool
1789 >     * supports it ({@link #getMaintainsParallelism}), this method
1790 >     * attempts to maintain the pool's nominal parallelism. Otherwise
1791 >     * it activates a thread only if necessary to avoid complete
1792 >     * starvation. This option may be preferable when blockages use
1793 >     * timeouts, or are almost always brief.
1794       *
1795 <     * <p> If the caller is not a ForkJoinTask, this method is behaviorally
1796 <     * equivalent to
1795 >     * <p>If the caller is not a {@link ForkJoinTask}, this method is
1796 >     * behaviorally equivalent to
1797       *  <pre> {@code
1798       * while (!blocker.isReleasable())
1799       *   if (blocker.block())
1800       *     return;
1801       * }</pre>
1802 <     * If the caller is a ForkJoinTask, then the pool may first
1803 <     * be expanded to ensure parallelism, and later adjusted.
1802 >     *
1803 >     * If the caller is a {@code ForkJoinTask}, then the pool may
1804 >     * first be expanded to ensure parallelism, and later adjusted.
1805       *
1806       * @param blocker the blocker
1807 <     * @param maintainParallelism if true and supported by this pool,
1808 <     * attempt to maintain the pool's nominal parallelism; otherwise
1809 <     * activate a thread only if necessary to avoid complete
1810 <     * starvation.
1807 >     * @param maintainParallelism if {@code true} and supported by
1808 >     * this pool, attempt to maintain the pool's nominal parallelism;
1809 >     * otherwise activate a thread only if necessary to avoid
1810 >     * complete starvation.
1811       * @throws InterruptedException if blocker.block did so
1812       */
1813      public static void managedBlock(ManagedBlocker blocker,
# Line 1866 | Line 1833 | public class ForkJoinPool extends Abstra
1833          do {} while (!blocker.isReleasable() && !blocker.block());
1834      }
1835  
1836 <    // AbstractExecutorService overrides
1836 >    // AbstractExecutorService overrides.  These rely on undocumented
1837 >    // fact that ForkJoinTask.adapt returns ForkJoinTasks that also
1838 >    // implement RunnableFuture.
1839  
1840      protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
1841 <        return new AdaptedRunnable<T>(runnable, value);
1841 >        return (RunnableFuture<T>) ForkJoinTask.adapt(runnable, value);
1842      }
1843  
1844      protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
1845 <        return new AdaptedCallable<T>(callable);
1845 >        return (RunnableFuture<T>) ForkJoinTask.adapt(callable);
1846      }
1847  
1848 <
1880 <    // Unsafe mechanics for jsr166y 3rd party package.
1881 <    private static sun.misc.Unsafe getUnsafe() {
1882 <        try {
1883 <            return sun.misc.Unsafe.getUnsafe();
1884 <        } catch (SecurityException se) {
1885 <            try {
1886 <                return java.security.AccessController.doPrivileged
1887 <                    (new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1888 <                        public sun.misc.Unsafe run() throws Exception {
1889 <                            return getUnsafeByReflection();
1890 <                        }});
1891 <            } catch (java.security.PrivilegedActionException e) {
1892 <                throw new RuntimeException("Could not initialize intrinsics",
1893 <                                           e.getCause());
1894 <            }
1895 <        }
1896 <    }
1897 <
1898 <    private static sun.misc.Unsafe getUnsafeByReflection()
1899 <            throws NoSuchFieldException, IllegalAccessException {
1900 <        java.lang.reflect.Field f =
1901 <            sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
1902 <        f.setAccessible(true);
1903 <        return (sun.misc.Unsafe) f.get(null);
1904 <    }
1905 <
1906 <    private static long fieldOffset(String fieldName, Class<?> klazz) {
1907 <        try {
1908 <            return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName));
1909 <        } catch (NoSuchFieldException e) {
1910 <            // Convert Exception to Error
1911 <            NoSuchFieldError error = new NoSuchFieldError(fieldName);
1912 <            error.initCause(e);
1913 <            throw error;
1914 <        }
1915 <    }
1848 >    // Unsafe mechanics
1849  
1850      private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1851 <    static final long eventCountOffset =
1852 <        fieldOffset("eventCount", ForkJoinPool.class);
1853 <    static final long workerCountsOffset =
1854 <        fieldOffset("workerCounts", ForkJoinPool.class);
1855 <    static final long runControlOffset =
1856 <        fieldOffset("runControl", ForkJoinPool.class);
1857 <    static final long syncStackOffset =
1858 <        fieldOffset("syncStack",ForkJoinPool.class);
1859 <    static final long spareStackOffset =
1860 <        fieldOffset("spareStack", ForkJoinPool.class);
1851 >    private static final long eventCountOffset =
1852 >        objectFieldOffset("eventCount", ForkJoinPool.class);
1853 >    private static final long workerCountsOffset =
1854 >        objectFieldOffset("workerCounts", ForkJoinPool.class);
1855 >    private static final long runControlOffset =
1856 >        objectFieldOffset("runControl", ForkJoinPool.class);
1857 >    private static final long syncStackOffset =
1858 >        objectFieldOffset("syncStack",ForkJoinPool.class);
1859 >    private static final long spareStackOffset =
1860 >        objectFieldOffset("spareStack", ForkJoinPool.class);
1861  
1862      private boolean casEventCount(long cmp, long val) {
1863          return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val);
# Line 1941 | Line 1874 | public class ForkJoinPool extends Abstra
1874      private boolean casBarrierStack(WaitQueueNode cmp, WaitQueueNode val) {
1875          return UNSAFE.compareAndSwapObject(this, syncStackOffset, cmp, val);
1876      }
1877 +
1878 +    private static long objectFieldOffset(String field, Class<?> klazz) {
1879 +        try {
1880 +            return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
1881 +        } catch (NoSuchFieldException e) {
1882 +            // Convert Exception to corresponding Error
1883 +            NoSuchFieldError error = new NoSuchFieldError(field);
1884 +            error.initCause(e);
1885 +            throw error;
1886 +        }
1887 +    }
1888 +
1889 +    /**
1890 +     * Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
1891 +     * Replace with a simple call to Unsafe.getUnsafe when integrating
1892 +     * into a jdk.
1893 +     *
1894 +     * @return a sun.misc.Unsafe
1895 +     */
1896 +    private static sun.misc.Unsafe getUnsafe() {
1897 +        try {
1898 +            return sun.misc.Unsafe.getUnsafe();
1899 +        } catch (SecurityException se) {
1900 +            try {
1901 +                return java.security.AccessController.doPrivileged
1902 +                    (new java.security
1903 +                     .PrivilegedExceptionAction<sun.misc.Unsafe>() {
1904 +                        public sun.misc.Unsafe run() throws Exception {
1905 +                            java.lang.reflect.Field f = sun.misc
1906 +                                .Unsafe.class.getDeclaredField("theUnsafe");
1907 +                            f.setAccessible(true);
1908 +                            return (sun.misc.Unsafe) f.get(null);
1909 +                        }});
1910 +            } catch (java.security.PrivilegedActionException e) {
1911 +                throw new RuntimeException("Could not initialize intrinsics",
1912 +                                           e.getCause());
1913 +            }
1914 +        }
1915 +    }
1916   }

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