java.util.concurrent
Class Semaphore.FairSync

java.lang.Object
  java.util.concurrent.locks.AbstractQueuedSynchronizer
      java.util.concurrent.Semaphore.Sync
          java.util.concurrent.Semaphore.FairSync

All Implemented Interfaces:

Serializable

Enclosing class:

Semaphore

static final class Semaphore.FairSync
extends Semaphore.Sync

Fair version

Nested Class Summary

Nested classes/interfaces inherited from class java.util.concurrent.locks.AbstractQueuedSynchronizer

AbstractQueuedSynchronizer.ConditionObject

Constructor Summary

Semaphore.FairSync(int permits)

Method Summary

protected int

tryAcquireShared(int acquires) Attempts to acquire in shared mode.

Methods inherited from class java.util.concurrent.Semaphore.Sync

drainPermits, getPermits, nonfairTryAcquireShared, reducePermits, tryReleaseShared

Methods inherited from class java.util.concurrent.locks.AbstractQueuedSynchronizer

acquire, acquireInterruptibly, acquireShared, acquireSharedInterruptibly, compareAndSetState, getExclusiveQueuedThreads, getFirstQueuedThread, getQueuedThreads, getQueueLength, getSharedQueuedThreads, getState, getWaitingThreads, getWaitQueueLength, hasContended, hasQueuedThreads, hasWaiters, isHeldExclusively, isQueued, owns, release, releaseShared, setState, toString, tryAcquire, tryAcquireNanos, tryAcquireSharedNanos, tryRelease

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Semaphore.FairSync

Semaphore.FairSync(int permits)

Method Detail

tryAcquireShared

protected int tryAcquireShared(int acquires)

Description copied from class: AbstractQueuedSynchronizer

Attempts to acquire in shared mode. This method should query if the state of the object permits it to be acquired in the shared mode, and if so to acquire it.

This method is always invoked by the thread performing acquire. If this method reports failure, the acquire method may queue the thread, if it is not already queued, until it is signalled by a release from some other thread.

The default implementation throws UnsupportedOperationException

Overrides:

tryAcquireShared in class AbstractQueuedSynchronizer

Parameters:

acquires - the acquire argument. This value is always the one passed to an acquire method, or is the value saved on entry to a condition wait. The value is otherwise uninterpreted and can represent anything you like.

Returns:

a negative value on failure, zero on exclusive success, and a positive value if non-exclusively successful, in which case a subsequent waiting thread must check availability. (Support for three different return values enables this method to be used in contexts where acquires only sometimes act exclusively.) Upon success, this object has been acquired.