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root/jsr166/jsr166/src/jsr166e/ForkJoinTask.java
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Comparing jsr166/src/jsr166e/ForkJoinTask.java (file contents):
Revision 1.11 by jsr166, Sun Jan 20 03:44:14 2013 UTC vs.
Revision 1.17 by jsr166, Thu Sep 3 22:54:46 2015 UTC

# Line 134 | Line 134 | import java.lang.reflect.Constructor;
134   * (DAG). Otherwise, executions may encounter a form of deadlock as
135   * tasks cyclically wait for each other.  However, this framework
136   * supports other methods and techniques (for example the use of
137 < * {@link java.util.concurrent.Phaser}, {@link #helpQuiesce}, and
138 < * {@link #complete}) that
137 > * {@link java.util.concurrent.Phaser Phaser}, {@link #helpQuiesce}, and {@link #complete}) that
138   * may be of use in constructing custom subclasses for problems that
139 < * are not statically structured as DAGs. To support such usages a
139 > * are not statically structured as DAGs. To support such usages, a
140   * ForkJoinTask may be atomically <em>tagged</em> with a {@code short}
141   * value using {@link #setForkJoinTaskTag} or {@link
142   * #compareAndSetForkJoinTaskTag} and checked using {@link
# Line 286 | Line 285 | public abstract class ForkJoinTask<V> im
285       */
286      private int externalAwaitDone() {
287          int s;
288 <        ForkJoinPool.externalHelpJoin(this);
289 <        boolean interrupted = false;
290 <        while ((s = status) >= 0) {
291 <            if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
292 <                synchronized (this) {
293 <                    if (status >= 0) {
294 <                        try {
295 <                            wait();
296 <                        } catch (InterruptedException ie) {
297 <                            interrupted = true;
288 >        ForkJoinPool cp = ForkJoinPool.common;
289 >        if ((s = status) >= 0) {
290 >            if (cp != null) {
291 >                if (this instanceof CountedCompleter)
292 >                    s = cp.externalHelpComplete((CountedCompleter<?>)this);
293 >                else if (cp.tryExternalUnpush(this))
294 >                    s = doExec();
295 >            }
296 >            if (s >= 0 && (s = status) >= 0) {
297 >                boolean interrupted = false;
298 >                do {
299 >                    if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
300 >                        synchronized (this) {
301 >                            if (status >= 0) {
302 >                                try {
303 >                                    wait();
304 >                                } catch (InterruptedException ie) {
305 >                                    interrupted = true;
306 >                                }
307 >                            }
308 >                            else
309 >                                notifyAll();
310                          }
311                      }
312 <                    else
313 <                        notifyAll();
314 <                }
312 >                } while ((s = status) >= 0);
313 >                if (interrupted)
314 >                    Thread.currentThread().interrupt();
315              }
316          }
306        if (interrupted)
307            Thread.currentThread().interrupt();
317          return s;
318      }
319  
# Line 313 | Line 322 | public abstract class ForkJoinTask<V> im
322       */
323      private int externalInterruptibleAwaitDone() throws InterruptedException {
324          int s;
325 +        ForkJoinPool cp = ForkJoinPool.common;
326          if (Thread.interrupted())
327              throw new InterruptedException();
328 <        ForkJoinPool.externalHelpJoin(this);
328 >        if ((s = status) >= 0 && cp != null) {
329 >            if (this instanceof CountedCompleter)
330 >                cp.externalHelpComplete((CountedCompleter<?>)this);
331 >            else if (cp.tryExternalUnpush(this))
332 >                doExec();
333 >        }
334          while ((s = status) >= 0) {
335              if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
336                  synchronized (this) {
# Line 396 | Line 411 | public abstract class ForkJoinTask<V> im
411          final Throwable ex;
412          ExceptionNode next;
413          final long thrower;  // use id not ref to avoid weak cycles
414 +        final int hashCode;  // store task hashCode before weak ref disappears
415          ExceptionNode(ForkJoinTask<?> task, Throwable ex, ExceptionNode next) {
416              super(task, exceptionTableRefQueue);
417              this.ex = ex;
418              this.next = next;
419              this.thrower = Thread.currentThread().getId();
420 +            this.hashCode = System.identityHashCode(task);
421          }
422      }
423  
# Line 469 | Line 486 | public abstract class ForkJoinTask<V> im
486      }
487  
488      /**
489 <     * Removes exception node and clears status
489 >     * Removes exception node and clears status.
490       */
491      private void clearExceptionalCompletion() {
492          int h = System.identityHashCode(this);
# Line 559 | Line 576 | public abstract class ForkJoinTask<V> im
576      /**
577       * Poll stale refs and remove them. Call only while holding lock.
578       */
579 +    /**
580 +     * Poll stale refs and remove them. Call only while holding lock.
581 +     */
582      private static void expungeStaleExceptions() {
583          for (Object x; (x = exceptionTableRefQueue.poll()) != null;) {
584              if (x instanceof ExceptionNode) {
585 <                ForkJoinTask<?> key = ((ExceptionNode)x).get();
585 >                int hashCode = ((ExceptionNode)x).hashCode;
586                  ExceptionNode[] t = exceptionTable;
587 <                int i = System.identityHashCode(key) & (t.length - 1);
587 >                int i = hashCode & (t.length - 1);
588                  ExceptionNode e = t[i];
589                  ExceptionNode pred = null;
590                  while (e != null) {
# Line 601 | Line 621 | public abstract class ForkJoinTask<V> im
621      /**
622       * A version of "sneaky throw" to relay exceptions
623       */
624 <    static void rethrow(final Throwable ex) {
625 <        if (ex != null) {
606 <            if (ex instanceof Error)
607 <                throw (Error)ex;
608 <            if (ex instanceof RuntimeException)
609 <                throw (RuntimeException)ex;
624 >    static void rethrow(Throwable ex) {
625 >        if (ex != null)
626              ForkJoinTask.<RuntimeException>uncheckedThrow(ex);
611        }
627      }
628  
629      /**
# Line 618 | Line 633 | public abstract class ForkJoinTask<V> im
633       */
634      @SuppressWarnings("unchecked") static <T extends Throwable>
635          void uncheckedThrow(Throwable t) throws T {
636 <        if (t != null)
622 <            throw (T)t; // rely on vacuous cast
636 >        throw (T)t; // rely on vacuous cast
637      }
638  
639      /**
# Line 773 | Line 787 | public abstract class ForkJoinTask<V> im
787       * unprocessed.
788       *
789       * @param tasks the collection of tasks
790 +     * @param <T> the type of the values returned from the tasks
791       * @return the tasks argument, to simplify usage
792       * @throws NullPointerException if tasks or any element are null
793       */
# Line 830 | Line 845 | public abstract class ForkJoinTask<V> im
845       * <p>This method is designed to be invoked by <em>other</em>
846       * tasks. To terminate the current task, you can just return or
847       * throw an unchecked exception from its computation method, or
848 <     * invoke {@link #completeExceptionally}.
848 >     * invoke {@link #completeExceptionally(Throwable)}.
849       *
850       * @param mayInterruptIfRunning this value has no effect in the
851       * default implementation because interrupts are not used to
# Line 982 | Line 997 | public abstract class ForkJoinTask<V> im
997          // Messy in part because we measure in nanosecs, but wait in millisecs
998          int s; long ms;
999          long ns = unit.toNanos(timeout);
1000 +        ForkJoinPool cp;
1001          if ((s = status) >= 0 && ns > 0L) {
1002              long deadline = System.nanoTime() + ns;
1003              ForkJoinPool p = null;
# Line 993 | Line 1009 | public abstract class ForkJoinTask<V> im
1009                  w = wt.workQueue;
1010                  p.helpJoinOnce(w, this); // no retries on failure
1011              }
1012 <            else
1013 <                ForkJoinPool.externalHelpJoin(this);
1012 >            else if ((cp = ForkJoinPool.common) != null) {
1013 >                if (this instanceof CountedCompleter)
1014 >                    cp.externalHelpComplete((CountedCompleter<?>)this);
1015 >                else if (cp.tryExternalUnpush(this))
1016 >                    doExec();
1017 >            }
1018              boolean canBlock = false;
1019              boolean interrupted = false;
1020              try {
# Line 1002 | Line 1022 | public abstract class ForkJoinTask<V> im
1022                      if (w != null && w.qlock < 0)
1023                          cancelIgnoringExceptions(this);
1024                      else if (!canBlock) {
1025 <                        if (p == null || p.tryCompensate())
1025 >                        if (p == null || p.tryCompensate(p.ctl))
1026                              canBlock = true;
1027                      }
1028                      else {
# Line 1143 | Line 1163 | public abstract class ForkJoinTask<V> im
1163          Thread t;
1164          return (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
1165                  ((ForkJoinWorkerThread)t).workQueue.tryUnpush(this) :
1166 <                ForkJoinPool.tryExternalUnpush(this));
1166 >                ForkJoinPool.common.tryExternalUnpush(this));
1167      }
1168  
1169      /**
# Line 1312 | Line 1332 | public abstract class ForkJoinTask<V> im
1332       *
1333       * @param e the expected tag value
1334       * @param tag the new tag value
1335 <     * @return true if successful; i.e., the current value was
1335 >     * @return {@code true} if successful; i.e., the current value was
1336       * equal to e and is now tag.
1337       * @since 1.8
1338       */
# Line 1327 | Line 1347 | public abstract class ForkJoinTask<V> im
1347      }
1348  
1349      /**
1350 <     * Adaptor for Runnables. This implements RunnableFuture
1350 >     * Adapter for Runnables. This implements RunnableFuture
1351       * to be compliant with AbstractExecutorService constraints
1352       * when used in ForkJoinPool.
1353       */
# Line 1348 | Line 1368 | public abstract class ForkJoinTask<V> im
1368      }
1369  
1370      /**
1371 <     * Adaptor for Runnables without results
1371 >     * Adapter for Runnables without results
1372       */
1373      static final class AdaptedRunnableAction extends ForkJoinTask<Void>
1374          implements RunnableFuture<Void> {
# Line 1365 | Line 1385 | public abstract class ForkJoinTask<V> im
1385      }
1386  
1387      /**
1388 <     * Adaptor for Callables
1388 >     * Adapter for Runnables in which failure forces worker exception
1389 >     */
1390 >    static final class RunnableExecuteAction extends ForkJoinTask<Void> {
1391 >        final Runnable runnable;
1392 >        RunnableExecuteAction(Runnable runnable) {
1393 >            if (runnable == null) throw new NullPointerException();
1394 >            this.runnable = runnable;
1395 >        }
1396 >        public final Void getRawResult() { return null; }
1397 >        public final void setRawResult(Void v) { }
1398 >        public final boolean exec() { runnable.run(); return true; }
1399 >        void internalPropagateException(Throwable ex) {
1400 >            rethrow(ex); // rethrow outside exec() catches.
1401 >        }
1402 >        private static final long serialVersionUID = 5232453952276885070L;
1403 >    }
1404 >
1405 >    /**
1406 >     * Adapter for Callables
1407       */
1408      static final class AdaptedCallable<T> extends ForkJoinTask<T>
1409          implements RunnableFuture<T> {
# Line 1412 | Line 1450 | public abstract class ForkJoinTask<V> im
1450       *
1451       * @param runnable the runnable action
1452       * @param result the result upon completion
1453 +     * @param <T> the type of the result
1454       * @return the task
1455       */
1456      public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) {
# Line 1425 | Line 1464 | public abstract class ForkJoinTask<V> im
1464       * encountered into {@code RuntimeException}.
1465       *
1466       * @param callable the callable action
1467 +     * @param <T> the type of the callable's result
1468       * @return the task
1469       */
1470      public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) {
# Line 1438 | Line 1478 | public abstract class ForkJoinTask<V> im
1478      /**
1479       * Saves this task to a stream (that is, serializes it).
1480       *
1481 +     * @param s the stream
1482 +     * @throws java.io.IOException if an I/O error occurs
1483       * @serialData the current run status and the exception thrown
1484       * during execution, or {@code null} if none
1485       */
# Line 1449 | Line 1491 | public abstract class ForkJoinTask<V> im
1491  
1492      /**
1493       * Reconstitutes this task from a stream (that is, deserializes it).
1494 +     * @param s the stream
1495 +     * @throws ClassNotFoundException if the class of a serialized object
1496 +     *         could not be found
1497 +     * @throws java.io.IOException if an I/O error occurs
1498       */
1499      private void readObject(java.io.ObjectInputStream s)
1500          throws java.io.IOException, ClassNotFoundException {

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