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Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.12 by jsr166, Tue Jul 21 18:11:44 2009 UTC vs.
Revision 1.19 by jsr166, Fri Jul 24 18:57:56 2009 UTC

# Line 56 | Line 56 | import java.lang.reflect.*;
56   * maximum number of running threads to 32767. Attempts to create
57   * pools with greater than the maximum result in
58   * IllegalArgumentExceptions.
59 + *
60 + * @since 1.7
61 + * @author Doug Lea
62   */
63   public class ForkJoinPool extends AbstractExecutorService {
64  
# Line 87 | Line 90 | public class ForkJoinPool extends Abstra
90      }
91  
92      /**
93 <     * Default ForkJoinWorkerThreadFactory implementation, creates a
93 >     * Default ForkJoinWorkerThreadFactory implementation; creates a
94       * new ForkJoinWorkerThread.
95       */
96      static class  DefaultForkJoinWorkerThreadFactory
# Line 181 | Line 184 | public class ForkJoinPool extends Abstra
184      private final LinkedTransferQueue<ForkJoinTask<?>> submissionQueue;
185  
186      /**
187 <     * Head of Treiber stack for barrier sync. See below for explanation
187 >     * Head of Treiber stack for barrier sync. See below for explanation.
188       */
189      private volatile WaitQueueNode syncStack;
190  
# Line 216 | Line 219 | public class ForkJoinPool extends Abstra
219       * threads, packed into one int to ensure consistent snapshot when
220       * making decisions about creating and suspending spare
221       * threads. Updated only by CAS.  Note: CASes in
222 <     * updateRunningCount and preJoin running active count is in low
223 <     * word, so need to be modified if this changes
222 >     * updateRunningCount and preJoin assume that running active count
223 >     * is in low word, so need to be modified if this changes.
224       */
225      private volatile int workerCounts;
226  
# Line 229 | Line 232 | public class ForkJoinPool extends Abstra
232       * Adds delta (which may be negative) to running count.  This must
233       * be called before (with negative arg) and after (with positive)
234       * any managed synchronization (i.e., mainly, joins).
235 +     *
236       * @param delta the number to add
237       */
238      final void updateRunningCount(int delta) {
239          int s;
240 <        do;while (!casWorkerCounts(s = workerCounts, s + delta));
240 >        do {} while (!casWorkerCounts(s = workerCounts, s + delta));
241      }
242  
243      /**
244       * Adds delta (which may be negative) to both total and running
245       * count.  This must be called upon creation and termination of
246       * worker threads.
247 +     *
248       * @param delta the number to add
249       */
250      private void updateWorkerCount(int delta) {
251          int d = delta + (delta << 16); // add to both lo and hi parts
252          int s;
253 <        do;while (!casWorkerCounts(s = workerCounts, s + d));
253 >        do {} while (!casWorkerCounts(s = workerCounts, s + d));
254      }
255  
256      /**
# Line 271 | Line 276 | public class ForkJoinPool extends Abstra
276      private static int runControlFor(int r, int a)   { return (r << 16) + a; }
277  
278      /**
279 <     * Try incrementing active count; fail on contention. Called by
280 <     * workers before/during executing tasks.
279 >     * Tries incrementing active count; fails on contention.
280 >     * Called by workers before/during executing tasks.
281 >     *
282       * @return true on success
283       */
284      final boolean tryIncrementActiveCount() {
# Line 284 | Line 290 | public class ForkJoinPool extends Abstra
290       * Tries decrementing active count; fails on contention.
291       * Possibly triggers termination on success.
292       * Called by workers when they can't find tasks.
293 +     *
294       * @return true on success
295       */
296      final boolean tryDecrementActiveCount() {
# Line 302 | Line 309 | public class ForkJoinPool extends Abstra
309       * terminating on shutdown.
310       */
311      private static boolean canTerminateOnShutdown(int c) {
312 <        return ((c & -c) >>> 16) != 0; // i.e. least bit is nonzero runState bit
312 >        // i.e. least bit is nonzero runState bit
313 >        return ((c & -c) >>> 16) != 0;
314      }
315  
316      /**
# Line 328 | Line 336 | public class ForkJoinPool extends Abstra
336  
337      /**
338       * Creates a ForkJoinPool with a pool size equal to the number of
339 <     * processors available on the system and using the default
340 <     * ForkJoinWorkerThreadFactory,
339 >     * processors available on the system, using the default
340 >     * ForkJoinWorkerThreadFactory.
341 >     *
342       * @throws SecurityException if a security manager exists and
343       *         the caller is not permitted to modify threads
344       *         because it does not hold {@link
345 <     *         java.lang.RuntimePermission}{@code ("modifyThread")},
345 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
346       */
347      public ForkJoinPool() {
348          this(Runtime.getRuntime().availableProcessors(),
# Line 342 | Line 351 | public class ForkJoinPool extends Abstra
351  
352      /**
353       * Creates a ForkJoinPool with the indicated parallelism level
354 <     * threads, and using the default ForkJoinWorkerThreadFactory,
354 >     * threads and using the default ForkJoinWorkerThreadFactory.
355 >     *
356       * @param parallelism the number of worker threads
357       * @throws IllegalArgumentException if parallelism less than or
358       * equal to zero
359       * @throws SecurityException if a security manager exists and
360       *         the caller is not permitted to modify threads
361       *         because it does not hold {@link
362 <     *         java.lang.RuntimePermission}{@code ("modifyThread")},
362 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
363       */
364      public ForkJoinPool(int parallelism) {
365          this(parallelism, defaultForkJoinWorkerThreadFactory);
# Line 358 | Line 368 | public class ForkJoinPool extends Abstra
368      /**
369       * Creates a ForkJoinPool with parallelism equal to the number of
370       * processors available on the system and using the given
371 <     * ForkJoinWorkerThreadFactory,
371 >     * ForkJoinWorkerThreadFactory.
372 >     *
373       * @param factory the factory for creating new threads
374       * @throws NullPointerException if factory is null
375       * @throws SecurityException if a security manager exists and
376       *         the caller is not permitted to modify threads
377       *         because it does not hold {@link
378 <     *         java.lang.RuntimePermission}{@code ("modifyThread")},
378 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
379       */
380      public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
381          this(Runtime.getRuntime().availableProcessors(), factory);
# Line 381 | Line 392 | public class ForkJoinPool extends Abstra
392       * @throws SecurityException if a security manager exists and
393       *         the caller is not permitted to modify threads
394       *         because it does not hold {@link
395 <     *         java.lang.RuntimePermission}{@code ("modifyThread")},
395 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
396       */
397      public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
398          if (parallelism <= 0 || parallelism > MAX_THREADS)
# Line 402 | Line 413 | public class ForkJoinPool extends Abstra
413      }
414  
415      /**
416 <     * Create new worker using factory.
416 >     * Creates a new worker thread using factory.
417 >     *
418       * @param index the index to assign worker
419       * @return new worker, or null of factory failed
420       */
# Line 424 | Line 436 | public class ForkJoinPool extends Abstra
436       * Returns a good size for worker array given pool size.
437       * Currently requires size to be a power of two.
438       */
439 <    private static int arraySizeFor(int ps) {
440 <        return ps <= 1? 1 : (1 << (32 - Integer.numberOfLeadingZeros(ps-1)));
439 >    private static int arraySizeFor(int poolSize) {
440 >        return (poolSize <= 1) ? 1 :
441 >            (1 << (32 - Integer.numberOfLeadingZeros(poolSize-1)));
442      }
443  
444      /**
445       * Creates or resizes array if necessary to hold newLength.
446 <     * Call only under exclusion or lock.
446 >     * Call only under exclusion.
447 >     *
448       * @return the array
449       */
450      private ForkJoinWorkerThread[] ensureWorkerArrayCapacity(int newLength) {
# Line 444 | Line 458 | public class ForkJoinPool extends Abstra
458      }
459  
460      /**
461 <     * Try to shrink workers into smaller array after one or more terminate
461 >     * Tries to shrink workers into smaller array after one or more terminate.
462       */
463      private void tryShrinkWorkerArray() {
464          ForkJoinWorkerThread[] ws = workers;
# Line 460 | Line 474 | public class ForkJoinPool extends Abstra
474      }
475  
476      /**
477 <     * Initialize workers if necessary
477 >     * Initializes workers if necessary.
478       */
479      final void ensureWorkerInitialization() {
480          ForkJoinWorkerThread[] ws = workers;
# Line 536 | Line 550 | public class ForkJoinPool extends Abstra
550      }
551  
552      /**
553 <     * Performs the given task; returning its result upon completion
553 >     * Performs the given task, returning its result upon completion.
554 >     *
555       * @param task the task
556       * @return the task's result
557       * @throws NullPointerException if task is null
# Line 549 | Line 564 | public class ForkJoinPool extends Abstra
564  
565      /**
566       * Arranges for (asynchronous) execution of the given task.
567 +     *
568       * @param task the task
569       * @throws NullPointerException if task is null
570       * @throws RejectedExecutionException if pool is shut down
# Line 583 | Line 599 | public class ForkJoinPool extends Abstra
599  
600      /**
601       * Adaptor for Runnables. This implements RunnableFuture
602 <     * to be compliant with AbstractExecutorService constraints
602 >     * to be compliant with AbstractExecutorService constraints.
603       */
604      static final class AdaptedRunnable<T> extends ForkJoinTask<T>
605          implements RunnableFuture<T> {
# Line 603 | Line 619 | public class ForkJoinPool extends Abstra
619              return true;
620          }
621          public void run() { invoke(); }
622 +        private static final long serialVersionUID = 5232453952276885070L;
623      }
624  
625      /**
# Line 631 | Line 648 | public class ForkJoinPool extends Abstra
648              }
649          }
650          public void run() { invoke(); }
651 +        private static final long serialVersionUID = 2838392045355241008L;
652      }
653  
654      public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
# Line 639 | Line 657 | public class ForkJoinPool extends Abstra
657          for (Callable<T> c : tasks)
658              ts.add(new AdaptedCallable<T>(c));
659          invoke(new InvokeAll<T>(ts));
660 <        return (List<Future<T>>)(List)ts;
660 >        return (List<Future<T>>) (List) ts;
661      }
662  
663      static final class InvokeAll<T> extends RecursiveAction {
664          final ArrayList<ForkJoinTask<T>> tasks;
665          InvokeAll(ArrayList<ForkJoinTask<T>> tasks) { this.tasks = tasks; }
666          public void compute() {
667 <            try { invokeAll(tasks); } catch(Exception ignore) {}
667 >            try { invokeAll(tasks); }
668 >            catch (Exception ignore) {}
669          }
670 +        private static final long serialVersionUID = -7914297376763021607L;
671      }
672  
673      // Configuration and status settings and queries
674  
675      /**
676 <     * Returns the factory used for constructing new workers
676 >     * Returns the factory used for constructing new workers.
677       *
678       * @return the factory used for constructing new workers
679       */
# Line 664 | Line 684 | public class ForkJoinPool extends Abstra
684      /**
685       * Returns the handler for internal worker threads that terminate
686       * due to unrecoverable errors encountered while executing tasks.
687 +     *
688       * @return the handler, or null if none
689       */
690      public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
# Line 689 | Line 710 | public class ForkJoinPool extends Abstra
710       * @throws SecurityException if a security manager exists and
711       *         the caller is not permitted to modify threads
712       *         because it does not hold {@link
713 <     *         java.lang.RuntimePermission}{@code ("modifyThread")},
713 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
714       */
715      public Thread.UncaughtExceptionHandler
716          setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
# Line 717 | Line 738 | public class ForkJoinPool extends Abstra
738  
739      /**
740       * Sets the target parallelism level of this pool.
741 +     *
742       * @param parallelism the target parallelism
743       * @throws IllegalArgumentException if parallelism less than or
744       * equal to zero or greater than maximum size bounds
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")},
748 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
749       */
750      public void setParallelism(int parallelism) {
751          checkPermission();
# Line 770 | Line 792 | public class ForkJoinPool extends Abstra
792      /**
793       * Returns the maximum number of threads allowed to exist in the
794       * pool, even if there are insufficient unblocked running threads.
795 +     *
796       * @return the maximum
797       */
798      public int getMaximumPoolSize() {
# Line 781 | Line 804 | public class ForkJoinPool extends Abstra
804       * pool, even if there are insufficient unblocked running threads.
805       * Setting this value has no effect on current pool size. It
806       * controls construction of new threads.
807 +     *
808       * @throws IllegalArgumentException if negative or greater then
809       * internal implementation limit
810       */
# Line 795 | Line 819 | public class ForkJoinPool extends Abstra
819       * Returns true if this pool dynamically maintains its target
820       * parallelism level. If false, new threads are added only to
821       * avoid possible starvation.
822 <     * This setting is by default true;
822 >     * This setting is by default true.
823 >     *
824       * @return true if maintains parallelism
825       */
826      public boolean getMaintainsParallelism() {
# Line 806 | Line 831 | public class ForkJoinPool extends Abstra
831       * Sets whether this pool dynamically maintains its target
832       * parallelism level. If false, new threads are added only to
833       * avoid possible starvation.
834 +     *
835       * @param enable true to maintains parallelism
836       */
837      public void setMaintainsParallelism(boolean enable) {
# Line 863 | Line 889 | public class ForkJoinPool extends Abstra
889       * Returns an estimate of the number of threads that are currently
890       * stealing or executing tasks. This method may overestimate the
891       * number of active threads.
892 +     *
893       * @return the number of active threads
894       */
895      public int getActiveThreadCount() {
# Line 873 | Line 900 | public class ForkJoinPool extends Abstra
900       * Returns an estimate of the number of threads that are currently
901       * idle waiting for tasks. This method may underestimate the
902       * number of idle threads.
903 +     *
904       * @return the number of idle threads
905       */
906      final int getIdleThreadCount() {
907          int c = runningCountOf(workerCounts) - activeCountOf(runControl);
908 <        return (c <= 0)? 0 : c;
908 >        return (c <= 0) ? 0 : c;
909      }
910  
911      /**
912       * Returns true if all worker threads are currently idle. An idle
913       * worker is one that cannot obtain a task to execute because none
914       * are available to steal from other threads, and there are no
915 <     * pending submissions to the pool. This method is conservative:
916 <     * It might not return true immediately upon idleness of all
915 >     * pending submissions to the pool. This method is conservative;
916 >     * it might not return true immediately upon idleness of all
917       * threads, but will eventually become true if threads remain
918       * inactive.
919 +     *
920       * @return true if all threads are currently idle
921       */
922      public boolean isQuiescent() {
# Line 899 | Line 928 | public class ForkJoinPool extends Abstra
928       * one thread's work queue by another. The reported value
929       * underestimates the actual total number of steals when the pool
930       * is not quiescent. This value may be useful for monitoring and
931 <     * tuning fork/join programs: In general, steal counts should be
931 >     * tuning fork/join programs: in general, steal counts should be
932       * high enough to keep threads busy, but low enough to avoid
933       * overhead and contention across threads.
934 +     *
935       * @return the number of steals
936       */
937      public long getStealCount() {
# Line 909 | Line 939 | public class ForkJoinPool extends Abstra
939      }
940  
941      /**
942 <     * Accumulate steal count from a worker. Call only
943 <     * when worker known to be idle.
942 >     * Accumulates steal count from a worker.
943 >     * Call only when worker known to be idle.
944       */
945      private void updateStealCount(ForkJoinWorkerThread w) {
946          int sc = w.getAndClearStealCount();
# Line 925 | Line 955 | public class ForkJoinPool extends Abstra
955       * an approximation, obtained by iterating across all threads in
956       * the pool. This method may be useful for tuning task
957       * granularities.
958 +     *
959       * @return the number of queued tasks
960       */
961      public long getQueuedTaskCount() {
# Line 944 | Line 975 | public class ForkJoinPool extends Abstra
975       * Returns an estimate of the number tasks submitted to this pool
976       * that have not yet begun executing. This method takes time
977       * proportional to the number of submissions.
978 +     *
979       * @return the number of queued submissions
980       */
981      public int getQueuedSubmissionCount() {
# Line 953 | Line 985 | public class ForkJoinPool extends Abstra
985      /**
986       * Returns true if there are any tasks submitted to this pool
987       * that have not yet begun executing.
988 +     *
989       * @return {@code true} if there are any queued submissions
990       */
991      public boolean hasQueuedSubmissions() {
# Line 963 | Line 996 | public class ForkJoinPool extends Abstra
996       * Removes and returns the next unexecuted submission if one is
997       * available.  This method may be useful in extensions to this
998       * class that re-assign work in systems with multiple pools.
999 +     *
1000       * @return the next submission, or null if none
1001       */
1002      protected ForkJoinTask<?> pollSubmission() {
# Line 982 | Line 1016 | public class ForkJoinPool extends Abstra
1016       * exception is thrown.  The behavior of this operation is
1017       * undefined if the specified collection is modified while the
1018       * operation is in progress.
1019 +     *
1020       * @param c the collection to transfer elements into
1021       * @return the number of elements transferred
1022       */
# Line 1042 | Line 1077 | public class ForkJoinPool extends Abstra
1077       * Invocation has no additional effect if already shut down.
1078       * Tasks that are in the process of being submitted concurrently
1079       * during the course of this method may or may not be rejected.
1080 +     *
1081       * @throws SecurityException if a security manager exists and
1082       *         the caller is not permitted to modify threads
1083       *         because it does not hold {@link
1084 <     *         java.lang.RuntimePermission}{@code ("modifyThread")},
1084 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
1085       */
1086      public void shutdown() {
1087          checkPermission();
# Line 1063 | Line 1099 | public class ForkJoinPool extends Abstra
1099       * upon termination, so always returns an empty list. However, you
1100       * can use method {@code drainTasksTo} before invoking this
1101       * method to transfer unexecuted tasks to another collection.
1102 +     *
1103       * @return an empty list
1104       * @throws SecurityException if a security manager exists and
1105       *         the caller is not permitted to modify threads
1106       *         because it does not hold {@link
1107 <     *         java.lang.RuntimePermission}{@code ("modifyThread")},
1107 >     *         java.lang.RuntimePermission}{@code ("modifyThread")}
1108       */
1109      public List<Runnable> shutdownNow() {
1110          checkPermission();
# Line 1135 | Line 1172 | public class ForkJoinPool extends Abstra
1172      // Shutdown and termination support
1173  
1174      /**
1175 <     * Callback from terminating worker. Null out the corresponding
1176 <     * workers slot, and if terminating, try to terminate, else try to
1177 <     * shrink workers array.
1175 >     * Callback from terminating worker. Nulls out the corresponding
1176 >     * workers slot, and if terminating, tries to terminate; else
1177 >     * tries to shrink workers array.
1178 >     *
1179       * @param w the worker
1180       */
1181      final void workerTerminated(ForkJoinWorkerThread w) {
# Line 1168 | Line 1206 | public class ForkJoinPool extends Abstra
1206      }
1207  
1208      /**
1209 <     * Initiate termination.
1209 >     * Initiates termination.
1210       */
1211      private void terminate() {
1212          if (transitionRunStateTo(TERMINATING)) {
# Line 1345 | Line 1383 | public class ForkJoinPool extends Abstra
1383       * Ensures that no thread is waiting for count to advance from the
1384       * current value of eventCount read on entry to this method, by
1385       * releasing waiting threads if necessary.
1386 +     *
1387       * @return the count
1388       */
1389      final long ensureSync() {
# Line 1366 | Line 1405 | public class ForkJoinPool extends Abstra
1405       */
1406      private void signalIdleWorkers() {
1407          long c;
1408 <        do;while (!casEventCount(c = eventCount, c+1));
1408 >        do {} while (!casEventCount(c = eventCount, c+1));
1409          ensureSync();
1410      }
1411  
# Line 1390 | Line 1429 | public class ForkJoinPool extends Abstra
1429       * Waits until event count advances from last value held by
1430       * caller, or if excess threads, caller is resumed as spare, or
1431       * caller or pool is terminating. Updates caller's event on exit.
1432 +     *
1433       * @param w the calling worker thread
1434       */
1435      final void sync(ForkJoinWorkerThread w) {
# Line 1420 | Line 1460 | public class ForkJoinPool extends Abstra
1460       * Returns true if worker waiting on sync can proceed:
1461       *  - on signal (thread == null)
1462       *  - on event count advance (winning race to notify vs signaller)
1463 <     *  - on Interrupt
1463 >     *  - on interrupt
1464       *  - if the first queued node, we find work available
1465       * If node was not signalled and event count not advanced on exit,
1466       * then we also help advance event count.
1467 +     *
1468       * @return true if node can be released
1469       */
1470      final boolean syncIsReleasable(WaitQueueNode node) {
# Line 1464 | Line 1505 | public class ForkJoinPool extends Abstra
1505       * spare thread when one is about to block (and remove or
1506       * suspend it later when unblocked -- see suspendIfSpare).
1507       * However, implementing this idea requires coping with
1508 <     * several problems: We have imperfect information about the
1508 >     * several problems: we have imperfect information about the
1509       * states of threads. Some count updates can and usually do
1510       * lag run state changes, despite arrangements to keep them
1511       * accurate (for example, when possible, updating counts
# Line 1487 | Line 1528 | public class ForkJoinPool extends Abstra
1528       * target counts, else create only to avoid starvation
1529       * @return true if joinMe known to be done
1530       */
1531 <    final boolean preJoin(ForkJoinTask<?> joinMe, boolean maintainParallelism) {
1531 >    final boolean preJoin(ForkJoinTask<?> joinMe,
1532 >                          boolean maintainParallelism) {
1533          maintainParallelism &= maintainsParallelism; // overrride
1534          boolean dec = false;  // true when running count decremented
1535          while (spareStack == null || !tryResumeSpare(dec)) {
1536              int counts = workerCounts;
1537 <            if (dec || (dec = casWorkerCounts(counts, --counts))) { // CAS cheat
1537 >            if (dec || (dec = casWorkerCounts(counts, --counts))) {
1538 >                // CAS cheat
1539                  if (!needSpare(counts, maintainParallelism))
1540                      break;
1541                  if (joinMe.status < 0)
# Line 1507 | Line 1550 | public class ForkJoinPool extends Abstra
1550      /**
1551       * Same idea as preJoin
1552       */
1553 <    final boolean preBlock(ManagedBlocker blocker, boolean maintainParallelism){
1553 >    final boolean preBlock(ManagedBlocker blocker,
1554 >                           boolean maintainParallelism) {
1555          maintainParallelism &= maintainsParallelism;
1556          boolean dec = false;
1557          while (spareStack == null || !tryResumeSpare(dec)) {
# Line 1531 | Line 1575 | public class ForkJoinPool extends Abstra
1575       * there is apparently some work to do.  This self-limiting rule
1576       * means that the more threads that have already been added, the
1577       * less parallelism we will tolerate before adding another.
1578 +     *
1579       * @param counts current worker counts
1580       * @param maintainParallelism try to maintain parallelism
1581       */
# Line 1550 | Line 1595 | public class ForkJoinPool extends Abstra
1595      /**
1596       * Adds a spare worker if lock available and no more than the
1597       * expected numbers of threads exist.
1598 +     *
1599       * @return true if successful
1600       */
1601      private boolean tryAddSpare(int expectedCounts) {
# Line 1609 | Line 1655 | public class ForkJoinPool extends Abstra
1655       * the same WaitQueueNodes as barriers.  They are resumed mainly
1656       * in preJoin, but are also woken on pool events that require all
1657       * threads to check run state.
1658 +     *
1659       * @param w the caller
1660       */
1661      private boolean suspendIfSpare(ForkJoinWorkerThread w) {
# Line 1619 | Line 1666 | public class ForkJoinPool extends Abstra
1666                  node = new WaitQueueNode(0, w);
1667              if (casWorkerCounts(s, s-1)) { // representation-dependent
1668                  // push onto stack
1669 <                do;while (!casSpareStack(node.next = spareStack, node));
1669 >                do {} while (!casSpareStack(node.next = spareStack, node));
1670                  // block until released by resumeSpare
1671                  node.awaitSpareRelease();
1672                  return true;
# Line 1630 | Line 1677 | public class ForkJoinPool extends Abstra
1677  
1678      /**
1679       * Tries to pop and resume a spare thread.
1680 +     *
1681       * @param updateCount if true, increment running count on success
1682       * @return true if successful
1683       */
# Line 1648 | Line 1696 | public class ForkJoinPool extends Abstra
1696  
1697      /**
1698       * Pops and resumes all spare threads. Same idea as ensureSync.
1699 +     *
1700       * @return true if any spares released
1701       */
1702      private boolean resumeAllSpares() {
# Line 1691 | Line 1740 | public class ForkJoinPool extends Abstra
1740       * Interface for extending managed parallelism for tasks running
1741       * in ForkJoinPools. A ManagedBlocker provides two methods.
1742       * Method {@code isReleasable} must return true if blocking is not
1743 <     * necessary. Method {@code block} blocks the current thread
1744 <     * if necessary (perhaps internally invoking isReleasable before
1745 <     * actually blocking.).
1743 >     * necessary. Method {@code block} blocks the current thread if
1744 >     * necessary (perhaps internally invoking {@code isReleasable}
1745 >     * before actually blocking.).
1746 >     *
1747       * <p>For example, here is a ManagedBlocker based on a
1748       * ReentrantLock:
1749 <     * <pre>
1750 <     *   class ManagedLocker implements ManagedBlocker {
1751 <     *     final ReentrantLock lock;
1752 <     *     boolean hasLock = false;
1753 <     *     ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1754 <     *     public boolean block() {
1755 <     *        if (!hasLock)
1756 <     *           lock.lock();
1757 <     *        return true;
1708 <     *     }
1709 <     *     public boolean isReleasable() {
1710 <     *        return hasLock || (hasLock = lock.tryLock());
1711 <     *     }
1749 >     *  <pre> {@code
1750 >     * class ManagedLocker implements ManagedBlocker {
1751 >     *   final ReentrantLock lock;
1752 >     *   boolean hasLock = false;
1753 >     *   ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1754 >     *   public boolean block() {
1755 >     *     if (!hasLock)
1756 >     *       lock.lock();
1757 >     *     return true;
1758       *   }
1759 <     * </pre>
1759 >     *   public boolean isReleasable() {
1760 >     *     return hasLock || (hasLock = lock.tryLock());
1761 >     *   }
1762 >     * }}</pre>
1763       */
1764      public static interface ManagedBlocker {
1765          /**
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)
1771           * @throws InterruptedException if interrupted while waiting
1772 <         * (the method is not required to do so, but is allowed to).
1772 >         * (the method is not required to do so, but is allowed to)
1773           */
1774          boolean block() throws InterruptedException;
1775  
# Line 1736 | Line 1786 | public class ForkJoinPool extends Abstra
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 if activates
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.
1793       *
1794       * <p> If the caller is not a ForkJoinTask, this method is behaviorally
1795       * equivalent to
1796 <     * <pre>
1797 <     *   while (!blocker.isReleasable())
1798 <     *      if (blocker.block())
1799 <     *         return;
1800 <     * </pre>
1796 >     *  <pre> {@code
1797 >     * while (!blocker.isReleasable())
1798 >     *   if (blocker.block())
1799 >     *     return;
1800 >     * }</pre>
1801       * If the caller is a ForkJoinTask, then the pool may first
1802       * be expanded to ensure parallelism, and later adjusted.
1803       *
# Line 1762 | Line 1812 | public class ForkJoinPool extends Abstra
1812                                      boolean maintainParallelism)
1813          throws InterruptedException {
1814          Thread t = Thread.currentThread();
1815 <        ForkJoinPool pool = (t instanceof ForkJoinWorkerThread?
1816 <                             ((ForkJoinWorkerThread)t).pool : null);
1815 >        ForkJoinPool pool = ((t instanceof ForkJoinWorkerThread) ?
1816 >                             ((ForkJoinWorkerThread) t).pool : null);
1817          if (!blocker.isReleasable()) {
1818              try {
1819                  if (pool == null ||
# Line 1778 | Line 1828 | public class ForkJoinPool extends Abstra
1828  
1829      private static void awaitBlocker(ManagedBlocker blocker)
1830          throws InterruptedException {
1831 <        do;while (!blocker.isReleasable() && !blocker.block());
1831 >        do {} while (!blocker.isReleasable() && !blocker.block());
1832      }
1833  
1834      // AbstractExecutorService overrides
1835  
1836      protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
1837 <        return new AdaptedRunnable(runnable, value);
1837 >        return new AdaptedRunnable<T>(runnable, value);
1838      }
1839  
1840      protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
1841 <        return new AdaptedCallable(callable);
1841 >        return new AdaptedCallable<T>(callable);
1842      }
1843  
1844  

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