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Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.14 by dl, Wed Jul 22 19:04:11 2009 UTC vs.
Revision 1.24 by dl, Sat Jul 25 17:49:01 2009 UTC

# Line 5 | Line 5
5   */
6  
7   package jsr166y;
8 < import java.util.*;
8 >
9   import java.util.concurrent.*;
10 < import java.util.concurrent.locks.*;
11 < import java.util.concurrent.atomic.*;
12 < import sun.misc.Unsafe;
13 < import java.lang.reflect.*;
10 >
11 > import java.util.ArrayList;
12 > import java.util.Arrays;
13 > import java.util.Collection;
14 > import java.util.Collections;
15 > import java.util.List;
16 > import java.util.concurrent.locks.Condition;
17 > import java.util.concurrent.locks.LockSupport;
18 > import java.util.concurrent.locks.ReentrantLock;
19 > import java.util.concurrent.atomic.AtomicInteger;
20 > import java.util.concurrent.atomic.AtomicLong;
21  
22   /**
23   * An {@link ExecutorService} for running {@link ForkJoinTask}s.  A
# Line 28 | Line 35 | import java.lang.reflect.*;
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 < * <tt>setAsyncMode</tt>, a ForkJoinPools may also be appropriate for
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.
# Line 38 | Line 45 | import java.lang.reflect.*;
45   * adding, suspending, or resuming threads, even if some tasks are
46   * waiting to join others. However, no such adjustments are performed
47   * in the face of blocked IO or other unmanaged synchronization. The
48 < * nested <code>ManagedBlocker</code> interface enables extension of
48 > * nested {@code ManagedBlocker} interface enables extension of
49   * the kinds of synchronization accommodated.  The target parallelism
50 < * level may also be changed dynamically (<code>setParallelism</code>)
50 > * level may also be changed dynamically ({@code setParallelism})
51   * and thread construction can be limited using methods
52 < * <code>setMaximumPoolSize</code> and/or
53 < * <code>setMaintainsParallelism</code>.
52 > * {@code setMaximumPoolSize} and/or
53 > * {@code setMaintainsParallelism}.
54   *
55   * <p>In addition to execution and lifecycle control methods, this
56   * class provides status check methods (for example
57 < * <code>getStealCount</code>) that are intended to aid in developing,
57 > * {@code getStealCount}) that are intended to aid in developing,
58   * tuning, and monitoring fork/join applications. Also, method
59 < * <code>toString</code> returns indications of pool state in a
59 > * {@code toString} returns indications of pool state in a
60   * convenient form for informal monitoring.
61   *
62   * <p><b>Implementation notes</b>: This implementation restricts the
63   * maximum number of running threads to 32767. Attempts to create
64   * pools with greater than the maximum result in
65   * IllegalArgumentExceptions.
66 + *
67 + * @since 1.7
68 + * @author Doug Lea
69   */
70   public class ForkJoinPool extends AbstractExecutorService {
71  
# Line 81 | Line 91 | public class ForkJoinPool extends Abstra
91           * Returns a new worker thread operating in the given pool.
92           *
93           * @param pool the pool this thread works in
94 <         * @throws NullPointerException if pool is null;
94 >         * @throws NullPointerException if pool is null
95           */
96          public ForkJoinWorkerThread newThread(ForkJoinPool pool);
97      }
98  
99      /**
100 <     * Default ForkJoinWorkerThreadFactory implementation, creates a
100 >     * Default ForkJoinWorkerThreadFactory implementation; creates a
101       * new ForkJoinWorkerThread.
102       */
103      static class  DefaultForkJoinWorkerThreadFactory
# Line 153 | Line 163 | public class ForkJoinPool extends Abstra
163  
164      /**
165       * The uncaught exception handler used when any worker
166 <     * abrupty terminates
166 >     * abruptly terminates
167       */
168      private Thread.UncaughtExceptionHandler ueh;
169  
# Line 181 | Line 191 | public class ForkJoinPool extends Abstra
191      private final LinkedTransferQueue<ForkJoinTask<?>> submissionQueue;
192  
193      /**
194 <     * Head of Treiber stack for barrier sync. See below for explanation
194 >     * Head of Treiber stack for barrier sync. See below for explanation.
195       */
196      private volatile WaitQueueNode syncStack;
197  
# Line 217 | Line 227 | public class ForkJoinPool extends Abstra
227       * making decisions about creating and suspending spare
228       * threads. Updated only by CAS.  Note: CASes in
229       * updateRunningCount and preJoin assume that running active count
230 <     * is in low word, so need to be modified if this changes
230 >     * is in low word, so need to be modified if this changes.
231       */
232      private volatile int workerCounts;
233  
# Line 226 | Line 236 | public class ForkJoinPool extends Abstra
236      private static int workerCountsFor(int t, int r) { return (t << 16) + r; }
237  
238      /**
239 <     * Add delta (which may be negative) to running count.  This must
239 >     * Adds delta (which may be negative) to running count.  This must
240       * be called before (with negative arg) and after (with positive)
241 <     * any managed synchronization (i.e., mainly, joins)
241 >     * any managed synchronization (i.e., mainly, joins).
242 >     *
243       * @param delta the number to add
244       */
245      final void updateRunningCount(int delta) {
246          int s;
247 <        do;while (!casWorkerCounts(s = workerCounts, s + delta));
247 >        do {} while (!casWorkerCounts(s = workerCounts, s + delta));
248      }
249  
250      /**
251 <     * Add delta (which may be negative) to both total and running
251 >     * Adds delta (which may be negative) to both total and running
252       * count.  This must be called upon creation and termination of
253       * worker threads.
254 +     *
255       * @param delta the number to add
256       */
257      private void updateWorkerCount(int delta) {
258          int d = delta + (delta << 16); // add to both lo and hi parts
259          int s;
260 <        do;while (!casWorkerCounts(s = workerCounts, s + d));
260 >        do {} while (!casWorkerCounts(s = workerCounts, s + d));
261      }
262  
263      /**
# Line 271 | Line 283 | public class ForkJoinPool extends Abstra
283      private static int runControlFor(int r, int a)   { return (r << 16) + a; }
284  
285      /**
286 <     * Try incrementing active count; fail on contention. Called by
287 <     * workers before/during executing tasks.
288 <     * @return true on success;
286 >     * Tries incrementing active count; fails on contention.
287 >     * Called by workers before/during executing tasks.
288 >     *
289 >     * @return true on success
290       */
291      final boolean tryIncrementActiveCount() {
292          int c = runControl;
# Line 281 | Line 294 | public class ForkJoinPool extends Abstra
294      }
295  
296      /**
297 <     * Try decrementing active count; fail on contention.
298 <     * Possibly trigger termination on success
297 >     * Tries decrementing active count; fails on contention.
298 >     * Possibly triggers termination on success.
299       * Called by workers when they can't find tasks.
300 +     *
301       * @return true on success
302       */
303      final boolean tryDecrementActiveCount() {
# Line 297 | Line 311 | public class ForkJoinPool extends Abstra
311      }
312  
313      /**
314 <     * Return true if argument represents zero active count and
314 >     * Returns true if argument represents zero active count and
315       * nonzero runstate, which is the triggering condition for
316       * terminating on shutdown.
317       */
318      private static boolean canTerminateOnShutdown(int c) {
319 <        return ((c & -c) >>> 16) != 0; // i.e. least bit is nonzero runState bit
319 >        // i.e. least bit is nonzero runState bit
320 >        return ((c & -c) >>> 16) != 0;
321      }
322  
323      /**
# Line 328 | Line 343 | public class ForkJoinPool extends Abstra
343  
344      /**
345       * Creates a ForkJoinPool with a pool size equal to the number of
346 <     * processors available on the system and using the default
347 <     * ForkJoinWorkerThreadFactory,
346 >     * processors available on the system, using the default
347 >     * ForkJoinWorkerThreadFactory.
348 >     *
349       * @throws SecurityException if a security manager exists and
350       *         the caller is not permitted to modify threads
351       *         because it does not hold {@link
352 <     *         java.lang.RuntimePermission}<code>("modifyThread")</code>,
352 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
353       */
354      public ForkJoinPool() {
355          this(Runtime.getRuntime().availableProcessors(),
# Line 341 | Line 357 | public class ForkJoinPool extends Abstra
357      }
358  
359      /**
360 <     * Creates a ForkJoinPool with the indicated parellelism level
361 <     * threads, and using the default ForkJoinWorkerThreadFactory,
360 >     * Creates a ForkJoinPool with the indicated parallelism level
361 >     * threads and using the default ForkJoinWorkerThreadFactory.
362 >     *
363       * @param parallelism the number of worker threads
364       * @throws IllegalArgumentException if parallelism less than or
365       * equal to zero
366       * @throws SecurityException if a security manager exists and
367       *         the caller is not permitted to modify threads
368       *         because it does not hold {@link
369 <     *         java.lang.RuntimePermission}<code>("modifyThread")</code>,
369 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
370       */
371      public ForkJoinPool(int parallelism) {
372          this(parallelism, defaultForkJoinWorkerThreadFactory);
# Line 358 | Line 375 | public class ForkJoinPool extends Abstra
375      /**
376       * Creates a ForkJoinPool with parallelism equal to the number of
377       * processors available on the system and using the given
378 <     * ForkJoinWorkerThreadFactory,
378 >     * ForkJoinWorkerThreadFactory.
379 >     *
380       * @param factory the factory for creating new threads
381       * @throws NullPointerException if factory is null
382       * @throws SecurityException if a security manager exists and
383       *         the caller is not permitted to modify threads
384       *         because it does not hold {@link
385 <     *         java.lang.RuntimePermission}<code>("modifyThread")</code>,
385 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
386       */
387      public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
388          this(Runtime.getRuntime().availableProcessors(), factory);
# Line 376 | Line 394 | public class ForkJoinPool extends Abstra
394       * @param parallelism the targeted number of worker threads
395       * @param factory the factory for creating new threads
396       * @throws IllegalArgumentException if parallelism less than or
397 <     * equal to zero, or greater than implementation limit.
397 >     * equal to zero, or greater than implementation limit
398       * @throws NullPointerException if factory is null
399       * @throws SecurityException if a security manager exists and
400       *         the caller is not permitted to modify threads
401       *         because it does not hold {@link
402 <     *         java.lang.RuntimePermission}<code>("modifyThread")</code>,
402 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
403       */
404      public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
405          if (parallelism <= 0 || parallelism > MAX_THREADS)
# Line 402 | Line 420 | public class ForkJoinPool extends Abstra
420      }
421  
422      /**
423 <     * Create new worker using factory.
423 >     * Creates a new worker thread using factory.
424 >     *
425       * @param index the index to assign worker
426       * @return new worker, or null of factory failed
427       */
# Line 421 | Line 440 | public class ForkJoinPool extends Abstra
440      }
441  
442      /**
443 <     * Return a good size for worker array given pool size.
443 >     * Returns a good size for worker array given pool size.
444       * Currently requires size to be a power of two.
445       */
446 <    private static int arraySizeFor(int ps) {
447 <        return ps <= 1? 1 : (1 << (32 - Integer.numberOfLeadingZeros(ps-1)));
446 >    private static int arraySizeFor(int poolSize) {
447 >        return (poolSize <= 1) ? 1 :
448 >            (1 << (32 - Integer.numberOfLeadingZeros(poolSize-1)));
449      }
450  
451      /**
452 <     * Create or resize array if necessary to hold newLength.
453 <     * Call only under exclusion
452 >     * Creates or resizes array if necessary to hold newLength.
453 >     * Call only under exclusion.
454 >     *
455       * @return the array
456       */
457      private ForkJoinWorkerThread[] ensureWorkerArrayCapacity(int newLength) {
# Line 444 | Line 465 | public class ForkJoinPool extends Abstra
465      }
466  
467      /**
468 <     * Try to shrink workers into smaller array after one or more terminate
468 >     * Tries to shrink workers into smaller array after one or more terminate.
469       */
470      private void tryShrinkWorkerArray() {
471          ForkJoinWorkerThread[] ws = workers;
# Line 460 | Line 481 | public class ForkJoinPool extends Abstra
481      }
482  
483      /**
484 <     * Initialize workers if necessary
484 >     * Initializes workers if necessary.
485       */
486      final void ensureWorkerInitialization() {
487          ForkJoinWorkerThread[] ws = workers;
# Line 527 | Line 548 | public class ForkJoinPool extends Abstra
548       * Common code for execute, invoke and submit
549       */
550      private <T> void doSubmit(ForkJoinTask<T> task) {
551 +        if (task == null)
552 +            throw new NullPointerException();
553          if (isShutdown())
554              throw new RejectedExecutionException();
555          if (workers == null)
# Line 536 | Line 559 | public class ForkJoinPool extends Abstra
559      }
560  
561      /**
562 <     * Performs the given task; returning its result upon completion
562 >     * Performs the given task, returning its result upon completion.
563 >     *
564       * @param task the task
565       * @return the task's result
566       * @throws NullPointerException if task is null
# Line 549 | Line 573 | public class ForkJoinPool extends Abstra
573  
574      /**
575       * Arranges for (asynchronous) execution of the given task.
576 +     *
577       * @param task the task
578       * @throws NullPointerException if task is null
579       * @throws RejectedExecutionException if pool is shut down
# Line 560 | Line 585 | public class ForkJoinPool extends Abstra
585      // AbstractExecutorService methods
586  
587      public void execute(Runnable task) {
588 <        doSubmit(new AdaptedRunnable<Void>(task, null));
588 >        ForkJoinTask<?> job;
589 >        if (task instanceof ForkJoinTask) // avoid re-wrap
590 >            job = (ForkJoinTask<?>)task;
591 >        else
592 >            job = new AdaptedRunnable<Void>(task, null);
593 >        doSubmit(job);
594      }
595  
596      public <T> ForkJoinTask<T> submit(Callable<T> task) {
# Line 576 | Line 606 | public class ForkJoinPool extends Abstra
606      }
607  
608      public ForkJoinTask<?> submit(Runnable task) {
609 <        ForkJoinTask<Void> job = new AdaptedRunnable<Void>(task, null);
609 >        ForkJoinTask<?> job;
610 >        if (task instanceof ForkJoinTask) // avoid re-wrap
611 >            job = (ForkJoinTask<?>)task;
612 >        else
613 >            job = new AdaptedRunnable<Void>(task, null);
614          doSubmit(job);
615          return job;
616      }
617  
618      /**
619 +     * Submits a ForkJoinTask for execution.
620 +     *
621 +     * @param task the task to submit
622 +     * @return the task
623 +     * @throws RejectedExecutionException if the task cannot be
624 +     *         scheduled for execution
625 +     * @throws NullPointerException if the task is null
626 +     */
627 +    public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
628 +        doSubmit(task);
629 +        return task;
630 +    }
631 +
632 +    /**
633       * Adaptor for Runnables. This implements RunnableFuture
634 <     * to be compliant with AbstractExecutorService constraints
634 >     * to be compliant with AbstractExecutorService constraints.
635       */
636      static final class AdaptedRunnable<T> extends ForkJoinTask<T>
637          implements RunnableFuture<T> {
# Line 603 | Line 651 | public class ForkJoinPool extends Abstra
651              return true;
652          }
653          public void run() { invoke(); }
654 +        private static final long serialVersionUID = 5232453952276885070L;
655      }
656  
657      /**
# Line 631 | Line 680 | public class ForkJoinPool extends Abstra
680              }
681          }
682          public void run() { invoke(); }
683 +        private static final long serialVersionUID = 2838392045355241008L;
684      }
685  
686      public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
687 <        ArrayList<ForkJoinTask<T>> ts =
687 >        ArrayList<ForkJoinTask<T>> forkJoinTasks =
688              new ArrayList<ForkJoinTask<T>>(tasks.size());
689 <        for (Callable<T> c : tasks)
690 <            ts.add(new AdaptedCallable<T>(c));
691 <        invoke(new InvokeAll<T>(ts));
692 <        return (List<Future<T>>)(List)ts;
689 >        for (Callable<T> task : tasks)
690 >            forkJoinTasks.add(new AdaptedCallable<T>(task));
691 >        invoke(new InvokeAll<T>(forkJoinTasks));
692 >
693 >        @SuppressWarnings({"unchecked", "rawtypes"})
694 >        List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks;
695 >        return futures;
696      }
697  
698      static final class InvokeAll<T> extends RecursiveAction {
699          final ArrayList<ForkJoinTask<T>> tasks;
700          InvokeAll(ArrayList<ForkJoinTask<T>> tasks) { this.tasks = tasks; }
701          public void compute() {
702 <            try { invokeAll(tasks); } catch(Exception ignore) {}
702 >            try { invokeAll(tasks); }
703 >            catch (Exception ignore) {}
704          }
705 +        private static final long serialVersionUID = -7914297376763021607L;
706      }
707  
708      // Configuration and status settings and queries
709  
710      /**
711 <     * Returns the factory used for constructing new workers
711 >     * Returns the factory used for constructing new workers.
712       *
713       * @return the factory used for constructing new workers
714       */
# Line 664 | Line 719 | public class ForkJoinPool extends Abstra
719      /**
720       * Returns the handler for internal worker threads that terminate
721       * due to unrecoverable errors encountered while executing tasks.
722 +     *
723       * @return the handler, or null if none
724       */
725      public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
# Line 689 | Line 745 | public class ForkJoinPool extends Abstra
745       * @throws SecurityException if a security manager exists and
746       *         the caller is not permitted to modify threads
747       *         because it does not hold {@link
748 <     *         java.lang.RuntimePermission}<code>("modifyThread")</code>,
748 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
749       */
750      public Thread.UncaughtExceptionHandler
751          setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
# Line 716 | Line 772 | public class ForkJoinPool extends Abstra
772  
773  
774      /**
775 <     * Sets the target paralleism level of this pool.
775 >     * Sets the target parallelism level of this pool.
776 >     *
777       * @param parallelism the target parallelism
778       * @throws IllegalArgumentException if parallelism less than or
779 <     * equal to zero or greater than maximum size bounds.
779 >     * equal to zero or greater than maximum size bounds
780       * @throws SecurityException if a security manager exists and
781       *         the caller is not permitted to modify threads
782       *         because it does not hold {@link
783 <     *         java.lang.RuntimePermission}<code>("modifyThread")</code>,
783 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
784       */
785      public void setParallelism(int parallelism) {
786          checkPermission();
# Line 758 | Line 815 | public class ForkJoinPool extends Abstra
815      /**
816       * Returns the number of worker threads that have started but not
817       * yet terminated.  This result returned by this method may differ
818 <     * from <code>getParallelism</code> when threads are created to
818 >     * from {@code getParallelism} when threads are created to
819       * maintain parallelism when others are cooperatively blocked.
820       *
821       * @return the number of worker threads
# Line 770 | Line 827 | public class ForkJoinPool extends Abstra
827      /**
828       * Returns the maximum number of threads allowed to exist in the
829       * pool, even if there are insufficient unblocked running threads.
830 +     *
831       * @return the maximum
832       */
833      public int getMaximumPoolSize() {
# Line 781 | Line 839 | public class ForkJoinPool extends Abstra
839       * pool, even if there are insufficient unblocked running threads.
840       * Setting this value has no effect on current pool size. It
841       * controls construction of new threads.
842 +     *
843       * @throws IllegalArgumentException if negative or greater then
844 <     * internal implementation limit.
844 >     * internal implementation limit
845       */
846      public void setMaximumPoolSize(int newMax) {
847          if (newMax < 0 || newMax > MAX_THREADS)
# Line 795 | Line 854 | public class ForkJoinPool extends Abstra
854       * Returns true if this pool dynamically maintains its target
855       * parallelism level. If false, new threads are added only to
856       * avoid possible starvation.
857 <     * This setting is by default true;
857 >     * This setting is by default true.
858 >     *
859       * @return true if maintains parallelism
860       */
861      public boolean getMaintainsParallelism() {
# Line 806 | Line 866 | public class ForkJoinPool extends Abstra
866       * Sets whether this pool dynamically maintains its target
867       * parallelism level. If false, new threads are added only to
868       * avoid possible starvation.
869 +     *
870       * @param enable true to maintains parallelism
871       */
872      public void setMaintainsParallelism(boolean enable) {
# Line 819 | Line 880 | public class ForkJoinPool extends Abstra
880       * worker threads only process asynchronous tasks.  This method is
881       * designed to be invoked only when pool is quiescent, and
882       * typically only before any tasks are submitted. The effects of
883 <     * invocations at ather times may be unpredictable.
883 >     * invocations at other times may be unpredictable.
884       *
885       * @param async if true, use locally FIFO scheduling
886 <     * @return the previous mode.
886 >     * @return the previous mode
887       */
888      public boolean setAsyncMode(boolean async) {
889          boolean oldMode = locallyFifo;
# Line 840 | Line 901 | public class ForkJoinPool extends Abstra
901  
902      /**
903       * Returns true if this pool uses local first-in-first-out
904 <     * scheduling mode for forked tasks that are never joined.
904 >     * scheduling mode for forked tasks that are never joined.
905       *
906 <     * @return true if this pool uses async mode.
906 >     * @return true if this pool uses async mode
907       */
908      public boolean getAsyncMode() {
909          return locallyFifo;
# Line 863 | Line 924 | public class ForkJoinPool extends Abstra
924       * Returns an estimate of the number of threads that are currently
925       * stealing or executing tasks. This method may overestimate the
926       * number of active threads.
927 <     * @return the number of active threads.
927 >     *
928 >     * @return the number of active threads
929       */
930      public int getActiveThreadCount() {
931          return activeCountOf(runControl);
# Line 873 | Line 935 | public class ForkJoinPool extends Abstra
935       * Returns an estimate of the number of threads that are currently
936       * idle waiting for tasks. This method may underestimate the
937       * number of idle threads.
938 <     * @return the number of idle threads.
938 >     *
939 >     * @return the number of idle threads
940       */
941      final int getIdleThreadCount() {
942          int c = runningCountOf(workerCounts) - activeCountOf(runControl);
943 <        return (c <= 0)? 0 : c;
943 >        return (c <= 0) ? 0 : c;
944      }
945  
946      /**
947       * Returns true if all worker threads are currently idle. An idle
948       * worker is one that cannot obtain a task to execute because none
949       * are available to steal from other threads, and there are no
950 <     * pending submissions to the pool. This method is conservative:
951 <     * It might not return true immediately upon idleness of all
950 >     * pending submissions to the pool. This method is conservative;
951 >     * it might not return true immediately upon idleness of all
952       * threads, but will eventually become true if threads remain
953       * inactive.
954 +     *
955       * @return true if all threads are currently idle
956       */
957      public boolean isQuiescent() {
# Line 899 | Line 963 | public class ForkJoinPool extends Abstra
963       * one thread's work queue by another. The reported value
964       * underestimates the actual total number of steals when the pool
965       * is not quiescent. This value may be useful for monitoring and
966 <     * tuning fork/join programs: In general, steal counts should be
966 >     * tuning fork/join programs: in general, steal counts should be
967       * high enough to keep threads busy, but low enough to avoid
968       * overhead and contention across threads.
969 <     * @return the number of steals.
969 >     *
970 >     * @return the number of steals
971       */
972      public long getStealCount() {
973          return stealCount.get();
974      }
975  
976      /**
977 <     * Accumulate steal count from a worker. Call only
978 <     * when worker known to be idle.
977 >     * Accumulates steal count from a worker.
978 >     * Call only when worker known to be idle.
979       */
980      private void updateStealCount(ForkJoinWorkerThread w) {
981          int sc = w.getAndClearStealCount();
# Line 925 | Line 990 | public class ForkJoinPool extends Abstra
990       * an approximation, obtained by iterating across all threads in
991       * the pool. This method may be useful for tuning task
992       * granularities.
993 <     * @return the number of queued tasks.
993 >     *
994 >     * @return the number of queued tasks
995       */
996      public long getQueuedTaskCount() {
997          long count = 0;
# Line 944 | Line 1010 | public class ForkJoinPool extends Abstra
1010       * Returns an estimate of the number tasks submitted to this pool
1011       * that have not yet begun executing. This method takes time
1012       * proportional to the number of submissions.
1013 <     * @return the number of queued submissions.
1013 >     *
1014 >     * @return the number of queued submissions
1015       */
1016      public int getQueuedSubmissionCount() {
1017          return submissionQueue.size();
# Line 953 | Line 1020 | public class ForkJoinPool extends Abstra
1020      /**
1021       * Returns true if there are any tasks submitted to this pool
1022       * that have not yet begun executing.
1023 <     * @return <code>true</code> if there are any queued submissions.
1023 >     *
1024 >     * @return {@code true} if there are any queued submissions
1025       */
1026      public boolean hasQueuedSubmissions() {
1027          return !submissionQueue.isEmpty();
# Line 963 | Line 1031 | public class ForkJoinPool extends Abstra
1031       * Removes and returns the next unexecuted submission if one is
1032       * available.  This method may be useful in extensions to this
1033       * class that re-assign work in systems with multiple pools.
1034 +     *
1035       * @return the next submission, or null if none
1036       */
1037      protected ForkJoinTask<?> pollSubmission() {
# Line 973 | Line 1042 | public class ForkJoinPool extends Abstra
1042       * Removes all available unexecuted submitted and forked tasks
1043       * from scheduling queues and adds them to the given collection,
1044       * without altering their execution status. These may include
1045 <     * artifically generated or wrapped tasks. This method id designed
1045 >     * artificially generated or wrapped tasks. This method is designed
1046       * to be invoked only when the pool is known to be
1047       * quiescent. Invocations at other times may not remove all
1048       * tasks. A failure encountered while attempting to add elements
1049 <     * to collection <tt>c</tt> may result in elements being in
1049 >     * to collection {@code c} may result in elements being in
1050       * neither, either or both collections when the associated
1051       * exception is thrown.  The behavior of this operation is
1052       * undefined if the specified collection is modified while the
1053       * operation is in progress.
1054 +     *
1055       * @param c the collection to transfer elements into
1056       * @return the number of elements transferred
1057       */
# Line 1042 | Line 1112 | public class ForkJoinPool extends Abstra
1112       * Invocation has no additional effect if already shut down.
1113       * Tasks that are in the process of being submitted concurrently
1114       * during the course of this method may or may not be rejected.
1115 +     *
1116       * @throws SecurityException if a security manager exists and
1117       *         the caller is not permitted to modify threads
1118       *         because it does not hold {@link
1119 <     *         java.lang.RuntimePermission}<code>("modifyThread")</code>,
1119 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
1120       */
1121      public void shutdown() {
1122          checkPermission();
# Line 1061 | Line 1132 | public class ForkJoinPool extends Abstra
1132       * method may or may not be rejected. Unlike some other executors,
1133       * this method cancels rather than collects non-executed tasks
1134       * upon termination, so always returns an empty list. However, you
1135 <     * can use method <code>drainTasksTo</code> before invoking this
1135 >     * can use method {@code drainTasksTo} before invoking this
1136       * method to transfer unexecuted tasks to another collection.
1137 +     *
1138       * @return an empty list
1139       * @throws SecurityException if a security manager exists and
1140       *         the caller is not permitted to modify threads
1141       *         because it does not hold {@link
1142 <     *         java.lang.RuntimePermission}<code>("modifyThread")</code>,
1142 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
1143       */
1144      public List<Runnable> shutdownNow() {
1145          checkPermission();
# Line 1076 | Line 1148 | public class ForkJoinPool extends Abstra
1148      }
1149  
1150      /**
1151 <     * Returns <code>true</code> if all tasks have completed following shut down.
1151 >     * Returns {@code true} if all tasks have completed following shut down.
1152       *
1153 <     * @return <code>true</code> if all tasks have completed following shut down
1153 >     * @return {@code true} if all tasks have completed following shut down
1154       */
1155      public boolean isTerminated() {
1156          return runStateOf(runControl) == TERMINATED;
1157      }
1158  
1159      /**
1160 <     * Returns <code>true</code> if the process of termination has
1160 >     * Returns {@code true} if the process of termination has
1161       * commenced but possibly not yet completed.
1162       *
1163 <     * @return <code>true</code> if terminating
1163 >     * @return {@code true} if terminating
1164       */
1165      public boolean isTerminating() {
1166          return runStateOf(runControl) >= TERMINATING;
1167      }
1168  
1169      /**
1170 <     * Returns <code>true</code> if this pool has been shut down.
1170 >     * Returns {@code true} if this pool has been shut down.
1171       *
1172 <     * @return <code>true</code> if this pool has been shut down
1172 >     * @return {@code true} if this pool has been shut down
1173       */
1174      public boolean isShutdown() {
1175          return runStateOf(runControl) >= SHUTDOWN;
# Line 1110 | Line 1182 | public class ForkJoinPool extends Abstra
1182       *
1183       * @param timeout the maximum time to wait
1184       * @param unit the time unit of the timeout argument
1185 <     * @return <code>true</code> if this executor terminated and
1186 <     *         <code>false</code> if the timeout elapsed before termination
1185 >     * @return {@code true} if this executor terminated and
1186 >     *         {@code false} if the timeout elapsed before termination
1187       * @throws InterruptedException if interrupted while waiting
1188       */
1189      public boolean awaitTermination(long timeout, TimeUnit unit)
# Line 1135 | Line 1207 | public class ForkJoinPool extends Abstra
1207      // Shutdown and termination support
1208  
1209      /**
1210 <     * Callback from terminating worker. Null out the corresponding
1211 <     * workers slot, and if terminating, try to terminate, else try to
1212 <     * shrink workers array.
1210 >     * Callback from terminating worker. Nulls out the corresponding
1211 >     * workers slot, and if terminating, tries to terminate; else
1212 >     * tries to shrink workers array.
1213 >     *
1214       * @param w the worker
1215       */
1216      final void workerTerminated(ForkJoinWorkerThread w) {
# Line 1168 | Line 1241 | public class ForkJoinPool extends Abstra
1241      }
1242  
1243      /**
1244 <     * Initiate termination.
1244 >     * Initiates termination.
1245       */
1246      private void terminate() {
1247          if (transitionRunStateTo(TERMINATING)) {
# Line 1183 | Line 1256 | public class ForkJoinPool extends Abstra
1256      }
1257  
1258      /**
1259 <     * Possibly terminate when on shutdown state
1259 >     * Possibly terminates when on shutdown state.
1260       */
1261      private void terminateOnShutdown() {
1262          if (!hasQueuedSubmissions() && canTerminateOnShutdown(runControl))
# Line 1191 | Line 1264 | public class ForkJoinPool extends Abstra
1264      }
1265  
1266      /**
1267 <     * Clear out and cancel submissions
1267 >     * Clears out and cancels submissions.
1268       */
1269      private void cancelQueuedSubmissions() {
1270          ForkJoinTask<?> task;
# Line 1200 | Line 1273 | public class ForkJoinPool extends Abstra
1273      }
1274  
1275      /**
1276 <     * Clean out worker queues.
1276 >     * Cleans out worker queues.
1277       */
1278      private void cancelQueuedWorkerTasks() {
1279          final ReentrantLock lock = this.workerLock;
# Line 1220 | Line 1293 | public class ForkJoinPool extends Abstra
1293      }
1294  
1295      /**
1296 <     * Set each worker's status to terminating. Requires lock to avoid
1297 <     * conflicts with add/remove
1296 >     * Sets each worker's status to terminating. Requires lock to avoid
1297 >     * conflicts with add/remove.
1298       */
1299      private void stopAllWorkers() {
1300          final ReentrantLock lock = this.workerLock;
# Line 1241 | Line 1314 | public class ForkJoinPool extends Abstra
1314      }
1315  
1316      /**
1317 <     * Interrupt all unterminated workers.  This is not required for
1317 >     * Interrupts all unterminated workers.  This is not required for
1318       * sake of internal control, but may help unstick user code during
1319       * shutdown.
1320       */
# Line 1311 | Line 1384 | public class ForkJoinPool extends Abstra
1384          }
1385  
1386          /**
1387 <         * Wake up waiter, returning false if known to already
1387 >         * Wakes up waiter, returning false if known to already
1388           */
1389          boolean signal() {
1390              ForkJoinWorkerThread t = thread;
# Line 1323 | Line 1396 | public class ForkJoinPool extends Abstra
1396          }
1397  
1398          /**
1399 <         * Await release on sync
1399 >         * Awaits release on sync.
1400           */
1401          void awaitSyncRelease(ForkJoinPool p) {
1402              while (thread != null && !p.syncIsReleasable(this))
# Line 1331 | Line 1404 | public class ForkJoinPool extends Abstra
1404          }
1405  
1406          /**
1407 <         * Await resumption as spare
1407 >         * Awaits resumption as spare.
1408           */
1409          void awaitSpareRelease() {
1410              while (thread != null) {
# Line 1345 | Line 1418 | public class ForkJoinPool extends Abstra
1418       * Ensures that no thread is waiting for count to advance from the
1419       * current value of eventCount read on entry to this method, by
1420       * releasing waiting threads if necessary.
1421 +     *
1422       * @return the count
1423       */
1424      final long ensureSync() {
# Line 1366 | Line 1440 | public class ForkJoinPool extends Abstra
1440       */
1441      private void signalIdleWorkers() {
1442          long c;
1443 <        do;while (!casEventCount(c = eventCount, c+1));
1443 >        do {} while (!casEventCount(c = eventCount, c+1));
1444          ensureSync();
1445      }
1446  
1447      /**
1448 <     * Signal threads waiting to poll a task. Because method sync
1448 >     * Signals threads waiting to poll a task. Because method sync
1449       * rechecks availability, it is OK to only proceed if queue
1450       * appears to be non-empty, and OK to skip under contention to
1451       * increment count (since some other thread succeeded).
# Line 1390 | Line 1464 | public class ForkJoinPool extends Abstra
1464       * Waits until event count advances from last value held by
1465       * caller, or if excess threads, caller is resumed as spare, or
1466       * caller or pool is terminating. Updates caller's event on exit.
1467 +     *
1468       * @param w the calling worker thread
1469       */
1470      final void sync(ForkJoinWorkerThread w) {
# Line 1420 | Line 1495 | public class ForkJoinPool extends Abstra
1495       * Returns true if worker waiting on sync can proceed:
1496       *  - on signal (thread == null)
1497       *  - on event count advance (winning race to notify vs signaller)
1498 <     *  - on Interrupt
1498 >     *  - on interrupt
1499       *  - if the first queued node, we find work available
1500       * If node was not signalled and event count not advanced on exit,
1501       * then we also help advance event count.
1502 +     *
1503       * @return true if node can be released
1504       */
1505      final boolean syncIsReleasable(WaitQueueNode node) {
# Line 1458 | Line 1534 | public class ForkJoinPool extends Abstra
1534      //  Parallelism maintenance
1535  
1536      /**
1537 <     * Decrement running count; if too low, add spare.
1537 >     * Decrements running count; if too low, adds spare.
1538       *
1539       * Conceptually, all we need to do here is add or resume a
1540       * spare thread when one is about to block (and remove or
1541       * suspend it later when unblocked -- see suspendIfSpare).
1542       * However, implementing this idea requires coping with
1543 <     * several problems: We have imperfect information about the
1543 >     * several problems: we have imperfect information about the
1544       * states of threads. Some count updates can and usually do
1545       * lag run state changes, despite arrangements to keep them
1546       * accurate (for example, when possible, updating counts
# Line 1478 | Line 1554 | public class ForkJoinPool extends Abstra
1554       * only be suspended or removed when they are idle, not
1555       * immediately when they aren't needed. So adding threads will
1556       * raise parallelism level for longer than necessary.  Also,
1557 <     * FJ applications often enounter highly transient peaks when
1557 >     * FJ applications often encounter highly transient peaks when
1558       * many threads are blocked joining, but for less time than it
1559       * takes to create or resume spares.
1560       *
# Line 1487 | Line 1563 | public class ForkJoinPool extends Abstra
1563       * target counts, else create only to avoid starvation
1564       * @return true if joinMe known to be done
1565       */
1566 <    final boolean preJoin(ForkJoinTask<?> joinMe, boolean maintainParallelism) {
1566 >    final boolean preJoin(ForkJoinTask<?> joinMe,
1567 >                          boolean maintainParallelism) {
1568          maintainParallelism &= maintainsParallelism; // overrride
1569          boolean dec = false;  // true when running count decremented
1570          while (spareStack == null || !tryResumeSpare(dec)) {
1571              int counts = workerCounts;
1572 <            if (dec || (dec = casWorkerCounts(counts, --counts))) { // CAS cheat
1572 >            if (dec || (dec = casWorkerCounts(counts, --counts))) {
1573 >                // CAS cheat
1574                  if (!needSpare(counts, maintainParallelism))
1575                      break;
1576                  if (joinMe.status < 0)
# Line 1507 | Line 1585 | public class ForkJoinPool extends Abstra
1585      /**
1586       * Same idea as preJoin
1587       */
1588 <    final boolean preBlock(ManagedBlocker blocker, boolean maintainParallelism){
1588 >    final boolean preBlock(ManagedBlocker blocker,
1589 >                           boolean maintainParallelism) {
1590          maintainParallelism &= maintainsParallelism;
1591          boolean dec = false;
1592          while (spareStack == null || !tryResumeSpare(dec)) {
# Line 1531 | Line 1610 | public class ForkJoinPool extends Abstra
1610       * there is apparently some work to do.  This self-limiting rule
1611       * means that the more threads that have already been added, the
1612       * less parallelism we will tolerate before adding another.
1613 +     *
1614       * @param counts current worker counts
1615       * @param maintainParallelism try to maintain parallelism
1616       */
# Line 1548 | Line 1628 | public class ForkJoinPool extends Abstra
1628      }
1629  
1630      /**
1631 <     * Add a spare worker if lock available and no more than the
1632 <     * expected numbers of threads exist
1631 >     * Adds a spare worker if lock available and no more than the
1632 >     * expected numbers of threads exist.
1633 >     *
1634       * @return true if successful
1635       */
1636      private boolean tryAddSpare(int expectedCounts) {
# Line 1582 | Line 1663 | public class ForkJoinPool extends Abstra
1663      }
1664  
1665      /**
1666 <     * Add the kth spare worker. On entry, pool coounts are already
1666 >     * Adds the kth spare worker. On entry, pool counts are already
1667       * adjusted to reflect addition.
1668       */
1669      private void createAndStartSpare(int k) {
# Line 1604 | Line 1685 | public class ForkJoinPool extends Abstra
1685      }
1686  
1687      /**
1688 <     * Suspend calling thread w if there are excess threads.  Called
1689 <     * only from sync.  Spares are enqueued in a Treiber stack
1690 <     * using the same WaitQueueNodes as barriers.  They are resumed
1691 <     * mainly in preJoin, but are also woken on pool events that
1692 <     * require all threads to check run state.
1688 >     * Suspends calling thread w if there are excess threads.  Called
1689 >     * only from sync.  Spares are enqueued in a Treiber stack using
1690 >     * the same WaitQueueNodes as barriers.  They are resumed mainly
1691 >     * in preJoin, but are also woken on pool events that require all
1692 >     * threads to check run state.
1693 >     *
1694       * @param w the caller
1695       */
1696      private boolean suspendIfSpare(ForkJoinWorkerThread w) {
# Line 1619 | Line 1701 | public class ForkJoinPool extends Abstra
1701                  node = new WaitQueueNode(0, w);
1702              if (casWorkerCounts(s, s-1)) { // representation-dependent
1703                  // push onto stack
1704 <                do;while (!casSpareStack(node.next = spareStack, node));
1704 >                do {} while (!casSpareStack(node.next = spareStack, node));
1705                  // block until released by resumeSpare
1706                  node.awaitSpareRelease();
1707                  return true;
# Line 1629 | Line 1711 | public class ForkJoinPool extends Abstra
1711      }
1712  
1713      /**
1714 <     * Try to pop and resume a spare thread.
1714 >     * Tries to pop and resume a spare thread.
1715 >     *
1716       * @param updateCount if true, increment running count on success
1717       * @return true if successful
1718       */
# Line 1647 | Line 1730 | public class ForkJoinPool extends Abstra
1730      }
1731  
1732      /**
1733 <     * Pop and resume all spare threads. Same idea as ensureSync.
1733 >     * Pops and resumes all spare threads. Same idea as ensureSync.
1734 >     *
1735       * @return true if any spares released
1736       */
1737      private boolean resumeAllSpares() {
# Line 1665 | Line 1749 | public class ForkJoinPool extends Abstra
1749      }
1750  
1751      /**
1752 <     * Pop and shutdown excessive spare threads. Call only while
1752 >     * Pops and shuts down excessive spare threads. Call only while
1753       * holding lock. This is not guaranteed to eliminate all excess
1754       * threads, only those suspended as spares, which are the ones
1755       * unlikely to be needed in the future.
# Line 1690 | Line 1774 | public class ForkJoinPool extends Abstra
1774      /**
1775       * Interface for extending managed parallelism for tasks running
1776       * in ForkJoinPools. A ManagedBlocker provides two methods.
1777 <     * Method <code>isReleasable</code> must return true if blocking is not
1778 <     * necessary. Method <code>block</code> blocks the current thread
1779 <     * if necessary (perhaps internally invoking isReleasable before
1780 <     * actually blocking.).
1777 >     * Method {@code isReleasable} must return true if blocking is not
1778 >     * necessary. Method {@code block} blocks the current thread if
1779 >     * necessary (perhaps internally invoking {@code isReleasable}
1780 >     * before actually blocking.).
1781 >     *
1782       * <p>For example, here is a ManagedBlocker based on a
1783       * ReentrantLock:
1784 <     * <pre>
1785 <     *   class ManagedLocker implements ManagedBlocker {
1786 <     *     final ReentrantLock lock;
1787 <     *     boolean hasLock = false;
1788 <     *     ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1789 <     *     public boolean block() {
1790 <     *        if (!hasLock)
1791 <     *           lock.lock();
1792 <     *        return true;
1793 <     *     }
1794 <     *     public boolean isReleasable() {
1795 <     *        return hasLock || (hasLock = lock.tryLock());
1711 <     *     }
1784 >     *  <pre> {@code
1785 >     * class ManagedLocker implements ManagedBlocker {
1786 >     *   final ReentrantLock lock;
1787 >     *   boolean hasLock = false;
1788 >     *   ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1789 >     *   public boolean block() {
1790 >     *     if (!hasLock)
1791 >     *       lock.lock();
1792 >     *     return true;
1793 >     *   }
1794 >     *   public boolean isReleasable() {
1795 >     *     return hasLock || (hasLock = lock.tryLock());
1796       *   }
1797 <     * </pre>
1797 >     * }}</pre>
1798       */
1799      public static interface ManagedBlocker {
1800          /**
1801           * Possibly blocks the current thread, for example waiting for
1802           * a lock or condition.
1803 +         *
1804           * @return true if no additional blocking is necessary (i.e.,
1805 <         * if isReleasable would return true).
1805 >         * if isReleasable would return true)
1806           * @throws InterruptedException if interrupted while waiting
1807 <         * (the method is not required to do so, but is allowe to).
1807 >         * (the method is not required to do so, but is allowed to)
1808           */
1809          boolean block() throws InterruptedException;
1810  
# Line 1734 | Line 1819 | public class ForkJoinPool extends Abstra
1819       * is a ForkJoinWorkerThread, this method possibly arranges for a
1820       * spare thread to be activated if necessary to ensure parallelism
1821       * while the current thread is blocked.  If
1822 <     * <code>maintainParallelism</code> is true and the pool supports
1822 >     * {@code maintainParallelism} is true and the pool supports
1823       * it ({@link #getMaintainsParallelism}), this method attempts to
1824 <     * maintain the pool's nominal parallelism. Otherwise if activates
1824 >     * maintain the pool's nominal parallelism. Otherwise it activates
1825       * a thread only if necessary to avoid complete starvation. This
1826       * option may be preferable when blockages use timeouts, or are
1827       * almost always brief.
1828       *
1829       * <p> If the caller is not a ForkJoinTask, this method is behaviorally
1830       * equivalent to
1831 <     * <pre>
1832 <     *   while (!blocker.isReleasable())
1833 <     *      if (blocker.block())
1834 <     *         return;
1835 <     * </pre>
1831 >     *  <pre> {@code
1832 >     * while (!blocker.isReleasable())
1833 >     *   if (blocker.block())
1834 >     *     return;
1835 >     * }</pre>
1836       * If the caller is a ForkJoinTask, then the pool may first
1837       * be expanded to ensure parallelism, and later adjusted.
1838       *
# Line 1756 | Line 1841 | public class ForkJoinPool extends Abstra
1841       * attempt to maintain the pool's nominal parallelism; otherwise
1842       * activate a thread only if necessary to avoid complete
1843       * starvation.
1844 <     * @throws InterruptedException if blocker.block did so.
1844 >     * @throws InterruptedException if blocker.block did so
1845       */
1846      public static void managedBlock(ManagedBlocker blocker,
1847                                      boolean maintainParallelism)
1848          throws InterruptedException {
1849          Thread t = Thread.currentThread();
1850 <        ForkJoinPool pool = (t instanceof ForkJoinWorkerThread?
1851 <                             ((ForkJoinWorkerThread)t).pool : null);
1850 >        ForkJoinPool pool = ((t instanceof ForkJoinWorkerThread) ?
1851 >                             ((ForkJoinWorkerThread) t).pool : null);
1852          if (!blocker.isReleasable()) {
1853              try {
1854                  if (pool == null ||
# Line 1778 | Line 1863 | public class ForkJoinPool extends Abstra
1863  
1864      private static void awaitBlocker(ManagedBlocker blocker)
1865          throws InterruptedException {
1866 <        do;while (!blocker.isReleasable() && !blocker.block());
1866 >        do {} while (!blocker.isReleasable() && !blocker.block());
1867      }
1868  
1869      // AbstractExecutorService overrides
1870  
1871      protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
1872 <        return new AdaptedRunnable(runnable, value);
1872 >        return new AdaptedRunnable<T>(runnable, value);
1873      }
1874  
1875      protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
1876 <        return new AdaptedCallable(callable);
1876 >        return new AdaptedCallable<T>(callable);
1877      }
1878  
1879  
1880 <    // Temporary Unsafe mechanics for preliminary release
1881 <    private static Unsafe getUnsafe() throws Throwable {
1880 >    // Unsafe mechanics for jsr166y 3rd party package.
1881 >    private static sun.misc.Unsafe getUnsafe() {
1882          try {
1883 <            return Unsafe.getUnsafe();
1883 >            return sun.misc.Unsafe.getUnsafe();
1884          } catch (SecurityException se) {
1885              try {
1886                  return java.security.AccessController.doPrivileged
1887 <                    (new java.security.PrivilegedExceptionAction<Unsafe>() {
1888 <                        public Unsafe run() throws Exception {
1889 <                            return getUnsafePrivileged();
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 e.getCause();
1892 >                throw new RuntimeException("Could not initialize intrinsics",
1893 >                                           e.getCause());
1894              }
1895          }
1896      }
1897  
1898 <    private static Unsafe getUnsafePrivileged()
1898 >    private static sun.misc.Unsafe getUnsafeByReflection()
1899              throws NoSuchFieldException, IllegalAccessException {
1900 <        Field f = Unsafe.class.getDeclaredField("theUnsafe");
1900 >        java.lang.reflect.Field f =
1901 >            sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
1902          f.setAccessible(true);
1903 <        return (Unsafe) f.get(null);
1903 >        return (sun.misc.Unsafe) f.get(null);
1904      }
1905  
1906 <    private static long fieldOffset(String fieldName)
1820 <            throws NoSuchFieldException {
1821 <        return _unsafe.objectFieldOffset
1822 <            (ForkJoinPool.class.getDeclaredField(fieldName));
1823 <    }
1824 <
1825 <    static final Unsafe _unsafe;
1826 <    static final long eventCountOffset;
1827 <    static final long workerCountsOffset;
1828 <    static final long runControlOffset;
1829 <    static final long syncStackOffset;
1830 <    static final long spareStackOffset;
1831 <
1832 <    static {
1906 >    private static long fieldOffset(String fieldName, Class<?> klazz) {
1907          try {
1908 <            _unsafe = getUnsafe();
1909 <            eventCountOffset = fieldOffset("eventCount");
1910 <            workerCountsOffset = fieldOffset("workerCounts");
1911 <            runControlOffset = fieldOffset("runControl");
1912 <            syncStackOffset = fieldOffset("syncStack");
1913 <            spareStackOffset = fieldOffset("spareStack");
1840 <        } catch (Throwable e) {
1841 <            throw new RuntimeException("Could not initialize intrinsics", e);
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      }
1916  
1917 +    private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1918 +    static final long eventCountOffset =
1919 +        fieldOffset("eventCount", ForkJoinPool.class);
1920 +    static final long workerCountsOffset =
1921 +        fieldOffset("workerCounts", ForkJoinPool.class);
1922 +    static final long runControlOffset =
1923 +        fieldOffset("runControl", ForkJoinPool.class);
1924 +    static final long syncStackOffset =
1925 +        fieldOffset("syncStack",ForkJoinPool.class);
1926 +    static final long spareStackOffset =
1927 +        fieldOffset("spareStack", ForkJoinPool.class);
1928 +
1929      private boolean casEventCount(long cmp, long val) {
1930 <        return _unsafe.compareAndSwapLong(this, eventCountOffset, cmp, val);
1930 >        return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val);
1931      }
1932      private boolean casWorkerCounts(int cmp, int val) {
1933 <        return _unsafe.compareAndSwapInt(this, workerCountsOffset, cmp, val);
1933 >        return UNSAFE.compareAndSwapInt(this, workerCountsOffset, cmp, val);
1934      }
1935      private boolean casRunControl(int cmp, int val) {
1936 <        return _unsafe.compareAndSwapInt(this, runControlOffset, cmp, val);
1936 >        return UNSAFE.compareAndSwapInt(this, runControlOffset, cmp, val);
1937      }
1938      private boolean casSpareStack(WaitQueueNode cmp, WaitQueueNode val) {
1939 <        return _unsafe.compareAndSwapObject(this, spareStackOffset, cmp, val);
1939 >        return UNSAFE.compareAndSwapObject(this, spareStackOffset, cmp, val);
1940      }
1941      private boolean casBarrierStack(WaitQueueNode cmp, WaitQueueNode val) {
1942 <        return _unsafe.compareAndSwapObject(this, syncStackOffset, cmp, val);
1942 >        return UNSAFE.compareAndSwapObject(this, syncStackOffset, cmp, val);
1943      }
1944   }

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