| 1 |
/* |
| 2 |
* Written by Doug Lea with assistance from members of JCP JSR-166 |
| 3 |
* Expert Group and released to the public domain, as explained at |
| 4 |
* http://creativecommons.org/licenses/publicdomain |
| 5 |
*/ |
| 6 |
|
| 7 |
package jsr166y.forkjoin; |
| 8 |
import java.util.concurrent.atomic.*; |
| 9 |
|
| 10 |
/** |
| 11 |
* Maintains lifecycle control for pool and workers. |
| 12 |
* Opportunistically subclasses AtomicInteger. Don't directly use the |
| 13 |
* AtomicInteger methods though. |
| 14 |
*/ |
| 15 |
final class RunState extends AtomicInteger { |
| 16 |
// Order among values matters |
| 17 |
static final int RUNNING = 0; |
| 18 |
static final int SHUTDOWN = 1; |
| 19 |
static final int STOPPING = 2; |
| 20 |
static final int TERMINATED = 4; |
| 21 |
|
| 22 |
boolean isRunning() { return get() == RUNNING; } |
| 23 |
boolean isShutdown() { return get() == SHUTDOWN; } |
| 24 |
boolean isStopping() { return get() == STOPPING; } |
| 25 |
boolean isTerminated() { return get() == TERMINATED; } |
| 26 |
boolean isAtLeastShutdown() { return get() >= SHUTDOWN; } |
| 27 |
boolean isAtLeastStopping() { return get() >= STOPPING; } |
| 28 |
boolean transitionToShutdown() { return transitionTo(SHUTDOWN); } |
| 29 |
boolean transitionToStopping() { return transitionTo(STOPPING); } |
| 30 |
boolean transitionToTerminated() { return transitionTo(TERMINATED); } |
| 31 |
|
| 32 |
/** |
| 33 |
* Transition to at least the given state. Return true if not |
| 34 |
* already at least given state. |
| 35 |
*/ |
| 36 |
private boolean transitionTo(int state) { |
| 37 |
for (;;) { |
| 38 |
int s = get(); |
| 39 |
if (s >= state) |
| 40 |
return false; |
| 41 |
if (compareAndSet(s, state)) |
| 42 |
return true; |
| 43 |
} |
| 44 |
} |
| 45 |
} |
