175 |
|
* parties result in IllegalStateExceptions. However, you can and |
176 |
|
* should create tiered phasers to accommodate arbitrarily large sets |
177 |
|
* of participants. |
178 |
+ |
* |
179 |
+ |
* @since 1.7 |
180 |
+ |
* @author Doug Lea |
181 |
|
*/ |
182 |
|
public class Phaser { |
183 |
|
/* |
215 |
|
} |
216 |
|
|
217 |
|
private static int partiesOf(long s) { |
218 |
< |
return ((int)s) >>> 16; |
218 |
> |
return ((int) s) >>> 16; |
219 |
|
} |
220 |
|
|
221 |
|
private static int phaseOf(long s) { |
222 |
< |
return (int)(s >>> 32); |
222 |
> |
return (int) (s >>> 32); |
223 |
|
} |
224 |
|
|
225 |
|
private static int arrivedOf(long s) { |
227 |
|
} |
228 |
|
|
229 |
|
private static long stateFor(int phase, int parties, int unarrived) { |
230 |
< |
return ((((long)phase) << 32) | (((long)parties) << 16) | |
231 |
< |
(long)unarrived); |
230 |
> |
return ((((long) phase) << 32) | (((long) parties) << 16) | |
231 |
> |
(long) unarrived); |
232 |
|
} |
233 |
|
|
234 |
|
private static long trippedStateFor(int phase, int parties) { |
235 |
< |
long lp = (long)parties; |
236 |
< |
return (((long)phase) << 32) | (lp << 16) | lp; |
235 |
> |
long lp = (long) parties; |
236 |
> |
return (((long) phase) << 32) | (lp << 16) | lp; |
237 |
|
} |
238 |
|
|
239 |
|
/** |
240 |
< |
* Returns message string for bad bounds exceptions |
240 |
> |
* Returns message string for bad bounds exceptions. |
241 |
|
*/ |
242 |
|
private static String badBounds(int parties, int unarrived) { |
243 |
|
return ("Attempt to set " + unarrived + |
312 |
|
/** |
313 |
|
* Creates a new Phaser with the given numbers of registered |
314 |
|
* unarrived parties, initial phase number 0, and no parent. |
315 |
< |
* @param parties the number of parties required to trip barrier. |
315 |
> |
* |
316 |
> |
* @param parties the number of parties required to trip barrier |
317 |
|
* @throws IllegalArgumentException if parties less than zero |
318 |
< |
* or greater than the maximum number of parties supported. |
318 |
> |
* or greater than the maximum number of parties supported |
319 |
|
*/ |
320 |
|
public Phaser(int parties) { |
321 |
|
this(null, parties); |
326 |
|
* initially registered parties. If parent is non-null this phaser |
327 |
|
* is registered with the parent and its initial phase number is |
328 |
|
* the same as that of parent phaser. |
329 |
< |
* @param parent the parent phaser. |
329 |
> |
* |
330 |
> |
* @param parent the parent phaser |
331 |
|
*/ |
332 |
|
public Phaser(Phaser parent) { |
333 |
|
int phase = 0; |
343 |
|
|
344 |
|
/** |
345 |
|
* Creates a new Phaser with the given parent and numbers of |
346 |
< |
* registered unarrived parties. If parent is non-null this phaser |
346 |
> |
* registered unarrived parties. If parent is non-null, this phaser |
347 |
|
* is registered with the parent and its initial phase number is |
348 |
|
* the same as that of parent phaser. |
349 |
< |
* @param parent the parent phaser. |
350 |
< |
* @param parties the number of parties required to trip barrier. |
349 |
> |
* |
350 |
> |
* @param parent the parent phaser |
351 |
> |
* @param parties the number of parties required to trip barrier |
352 |
|
* @throws IllegalArgumentException if parties less than zero |
353 |
< |
* or greater than the maximum number of parties supported. |
353 |
> |
* or greater than the maximum number of parties supported |
354 |
|
*/ |
355 |
|
public Phaser(Phaser parent, int parties) { |
356 |
|
if (parties < 0 || parties > ushortMask) |
368 |
|
|
369 |
|
/** |
370 |
|
* Adds a new unarrived party to this phaser. |
371 |
+ |
* |
372 |
|
* @return the current barrier phase number upon registration |
373 |
|
* @throws IllegalStateException if attempting to register more |
374 |
< |
* than the maximum supported number of parties. |
374 |
> |
* than the maximum supported number of parties |
375 |
|
*/ |
376 |
|
public int register() { |
377 |
|
return doRegister(1); |
379 |
|
|
380 |
|
/** |
381 |
|
* Adds the given number of new unarrived parties to this phaser. |
382 |
< |
* @param parties the number of parties required to trip barrier. |
382 |
> |
* |
383 |
> |
* @param parties the number of parties required to trip barrier |
384 |
|
* @return the current barrier phase number upon registration |
385 |
|
* @throws IllegalStateException if attempting to register more |
386 |
< |
* than the maximum supported number of parties. |
386 |
> |
* than the maximum supported number of parties |
387 |
|
*/ |
388 |
|
public int bulkRegister(int parties) { |
389 |
|
if (parties < 0) |
419 |
|
* in turn wait for others via {@link #awaitAdvance}). |
420 |
|
* |
421 |
|
* @return the barrier phase number upon entry to this method, or a |
422 |
< |
* negative value if terminated; |
422 |
> |
* negative value if terminated |
423 |
|
* @throws IllegalStateException if not terminated and the number |
424 |
< |
* of unarrived parties would become negative. |
424 |
> |
* of unarrived parties would become negative |
425 |
|
*/ |
426 |
|
public int arrive() { |
427 |
|
int phase; |
471 |
|
* zero parties, this phaser is also deregistered from its parent. |
472 |
|
* |
473 |
|
* @return the current barrier phase number upon entry to |
474 |
< |
* this method, or a negative value if terminated; |
474 |
> |
* this method, or a negative value if terminated |
475 |
|
* @throws IllegalStateException if not terminated and the number |
476 |
< |
* of registered or unarrived parties would become negative. |
476 |
> |
* of registered or unarrived parties would become negative |
477 |
|
*/ |
478 |
|
public int arriveAndDeregister() { |
479 |
|
// similar code to arrive, but too different to merge |
524 |
|
* to {@code awaitAdvance(arrive())}. If you instead need to |
525 |
|
* await with interruption of timeout, and/or deregister upon |
526 |
|
* arrival, you can arrange them using analogous constructions. |
527 |
+ |
* |
528 |
|
* @return the phase on entry to this method |
529 |
|
* @throws IllegalStateException if not terminated and the number |
530 |
< |
* of unarrived parties would become negative. |
530 |
> |
* of unarrived parties would become negative |
531 |
|
*/ |
532 |
|
public int arriveAndAwaitAdvance() { |
533 |
|
return awaitAdvance(arrive()); |
537 |
|
* Awaits the phase of the barrier to advance from the given |
538 |
|
* value, or returns immediately if argument is negative or this |
539 |
|
* barrier is terminated. |
540 |
+ |
* |
541 |
|
* @param phase the phase on entry to this method |
542 |
|
* @return the phase on exit from this method |
543 |
|
*/ |
559 |
|
* value, or returns immediately if argument is negative or this |
560 |
|
* barrier is terminated, or throws InterruptedException if |
561 |
|
* interrupted while waiting. |
562 |
+ |
* |
563 |
|
* @param phase the phase on entry to this method |
564 |
|
* @return the phase on exit from this method |
565 |
|
* @throws InterruptedException if thread interrupted while waiting |
581 |
|
* Awaits the phase of the barrier to advance from the given value |
582 |
|
* or the given timeout elapses, or returns immediately if |
583 |
|
* argument is negative or this barrier is terminated. |
584 |
+ |
* |
585 |
|
* @param phase the phase on entry to this method |
586 |
|
* @return the phase on exit from this method |
587 |
|
* @throws InterruptedException if thread interrupted while waiting |
628 |
|
* Returns the current phase number. The maximum phase number is |
629 |
|
* {@code Integer.MAX_VALUE}, after which it restarts at |
630 |
|
* zero. Upon termination, the phase number is negative. |
631 |
+ |
* |
632 |
|
* @return the phase number, or a negative value if terminated |
633 |
|
*/ |
634 |
|
public final int getPhase() { |
637 |
|
|
638 |
|
/** |
639 |
|
* Returns {@code true} if the current phase number equals the given phase. |
640 |
+ |
* |
641 |
|
* @param phase the phase |
642 |
|
* @return {@code true} if the current phase number equals the given phase |
643 |
|
*/ |
647 |
|
|
648 |
|
/** |
649 |
|
* Returns the number of parties registered at this barrier. |
650 |
+ |
* |
651 |
|
* @return the number of parties |
652 |
|
*/ |
653 |
|
public int getRegisteredParties() { |
657 |
|
/** |
658 |
|
* Returns the number of parties that have arrived at the current |
659 |
|
* phase of this barrier. |
660 |
+ |
* |
661 |
|
* @return the number of arrived parties |
662 |
|
*/ |
663 |
|
public int getArrivedParties() { |
667 |
|
/** |
668 |
|
* Returns the number of registered parties that have not yet |
669 |
|
* arrived at the current phase of this barrier. |
670 |
+ |
* |
671 |
|
* @return the number of unarrived parties |
672 |
|
*/ |
673 |
|
public int getUnarrivedParties() { |
676 |
|
|
677 |
|
/** |
678 |
|
* Returns the parent of this phaser, or null if none. |
679 |
+ |
* |
680 |
|
* @return the parent of this phaser, or null if none |
681 |
|
*/ |
682 |
|
public Phaser getParent() { |
686 |
|
/** |
687 |
|
* Returns the root ancestor of this phaser, which is the same as |
688 |
|
* this phaser if it has no parent. |
689 |
+ |
* |
690 |
|
* @return the root ancestor of this phaser |
691 |
|
*/ |
692 |
|
public Phaser getRoot() { |
695 |
|
|
696 |
|
/** |
697 |
|
* Returns {@code true} if this barrier has been terminated. |
698 |
+ |
* |
699 |
|
* @return {@code true} if this barrier has been terminated |
700 |
|
*/ |
701 |
|
public boolean isTerminated() { |
819 |
|
} |
820 |
|
|
821 |
|
/** |
822 |
< |
* Removes and signals waiting threads from wait queue |
822 |
> |
* Removes and signals waiting threads from wait queue. |
823 |
|
*/ |
824 |
|
private void releaseWaiters(int phase) { |
825 |
|
AtomicReference<QNode> head = queueFor(phase); |
831 |
|
} |
832 |
|
|
833 |
|
/** |
834 |
< |
* Tries to enqueue given node in the appropriate wait queue |
834 |
> |
* Tries to enqueue given node in the appropriate wait queue. |
835 |
> |
* |
836 |
|
* @return true if successful |
837 |
|
*/ |
838 |
|
private boolean tryEnqueue(QNode node) { |
842 |
|
|
843 |
|
/** |
844 |
|
* Enqueues node and waits unless aborted or signalled. |
845 |
+ |
* |
846 |
|
* @return current phase |
847 |
|
*/ |
848 |
|
private int untimedWait(int phase) { |
956 |
|
|
957 |
|
private static long fieldOffset(String fieldName) |
958 |
|
throws NoSuchFieldException { |
959 |
< |
return _unsafe.objectFieldOffset |
959 |
> |
return UNSAFE.objectFieldOffset |
960 |
|
(Phaser.class.getDeclaredField(fieldName)); |
961 |
|
} |
962 |
|
|
963 |
< |
static final Unsafe _unsafe; |
963 |
> |
static final Unsafe UNSAFE; |
964 |
|
static final long stateOffset; |
965 |
|
|
966 |
|
static { |
967 |
|
try { |
968 |
< |
_unsafe = getUnsafe(); |
968 |
> |
UNSAFE = getUnsafe(); |
969 |
|
stateOffset = fieldOffset("state"); |
970 |
|
} catch (Throwable e) { |
971 |
|
throw new RuntimeException("Could not initialize intrinsics", e); |
973 |
|
} |
974 |
|
|
975 |
|
final boolean casState(long cmp, long val) { |
976 |
< |
return _unsafe.compareAndSwapLong(this, stateOffset, cmp, val); |
976 |
> |
return UNSAFE.compareAndSwapLong(this, stateOffset, cmp, val); |
977 |
|
} |
978 |
|
} |