org.metasyntactic.thread.concurrent
Class PrioritySemaphore

java.lang.Object
  |
  +--org.metasyntactic.thread.concurrent.Semaphore
        |
        +--org.metasyntactic.thread.concurrent.QueuedSemaphore
              |
              +--org.metasyntactic.thread.concurrent.PrioritySemaphore

All Implemented Interfaces:

Monitor

public class PrioritySemaphore

extends QueuedSemaphore

A Semaphore that grants requests to threads with higher Thread priority rather than lower priority when there is contention. Ordering of requests with the same priority is approximately FIFO. Priorities are based on Thread.getPriority. Changing the priority of an already-waiting thread does NOT change its ordering. This class also does not specially deal with priority inversion -- when a new high-priority thread enters while a low-priority thread is currently running, their priorities are not artificially manipulated.

Nested Class Summary

Nested classes inherited from class org.metasyntactic.thread.concurrent.QueuedSemaphore

QueuedSemaphore.WaitQueue

Field Summary

Fields inherited from class org.metasyntactic.thread.concurrent.Semaphore

permits

Fields inherited from interface org.metasyntactic.thread.concurrent.Monitor

ONE_CENTURY, ONE_DAY, ONE_HOUR, ONE_MINUTE, ONE_SECOND, ONE_WEEK, ONE_YEAR

Constructor Summary

PrioritySemaphore(long initialPermits)
Create a Semaphore with the given initial number of permits.

Methods inherited from class org.metasyntactic.thread.concurrent.QueuedSemaphore

acquire, attempt, release, release

Methods inherited from class org.metasyntactic.thread.concurrent.Semaphore

permits

Methods inherited from class java.lang.Object

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

Constructor Detail

PrioritySemaphore

public PrioritySemaphore(long initialPermits)

Create a Semaphore with the given initial number of permits. Using a seed of one makes the semaphore act as a mutual exclusion lock. Negative seeds are also allowed, in which case no acquires will proceed until the number of releases has pushed the number of permits past 0.

Parameters:

initialPermits -