pt.ua.concurrent

Class Semaphore

java.lang.Object

pt.ua.concurrent.CObject

pt.ua.concurrent.Semaphore

All Implemented Interfaces:

InterruptibleAwaitingThreads, SyncCV

Direct Known Subclasses:

BoundedSemaphore

public class Semaphore
extends CObject

A standard counting semaphore class.

This class follows DbC(tm) methodology (Wikipedia). Where possible, contracts are implement with native's Java assert.

Version:

0.5, November 2011

Author:

Miguel Oliveira e Silva (mos@ua.pt)

Constructor Summary

Constructors

Constructor and Description
Semaphore() Creates a semaphore initialized with a zero counter and registering waiting threads.
Semaphore(int initialCount) Creates a semaphore initialized with a given counter and registering waiting threads.
Semaphore(int initialCount, boolean registerAwaitingThreads) Creates a semaphore initialized with a given counter.

Method Summary

Modifier and Type	Method and Description
void	acquire() Acquires (decrements) the semaphore.
void	release() Releases (increments) the semaphore.

Methods inherited from class pt.ua.concurrent.CObject

await, await, await, broadcast, interruptWaitingThreads, lockIsMine, registerAwaitingThreads, signal, syncronizedLockIsMine

Methods inherited from class java.lang.Object

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

Constructor Detail

Semaphore

public Semaphore()

Creates a semaphore initialized with a zero counter and registering waiting threads.

Semaphore

public Semaphore(int initialCount)

Creates a semaphore initialized with a given counter and registering waiting threads.

Precondition:

initialCount >= 0 - non negative counter

Parameters:

initialCount - value

Semaphore

public Semaphore(int initialCount,
                 boolean registerAwaitingThreads)

Creates a semaphore initialized with a given counter.

Precondition:

initialCount >= 0 - non negative counter

Parameters:

initialCount - value

registerAwaitingThreads - if true, threads are registered when waiting

Method Detail

acquire

public void acquire()

Acquires (decrements) the semaphore.

release

public void release()

Releases (increments) the semaphore.