oracle.ifs.utils.common

Class Semaphore

java.lang.Object

oracle.ifs.utils.common.Semaphore

public class Semaphore
extends Object

This is an implementation of a semaphore. It provides the basic semaphore operations up() and down(). Semaphores have an internal counter. The up operation always increments this counter. If the counter is positive, then down() decrements the counter. If the counter is not positive, then down() blocks until a call to up() is made. When multiple threads are blocked in a call to down(), one call to up() will allow exactly one of those threads to return from the down() method.

Constructor Summary

Constructors

Constructor and Description
Semaphore() Construct a Semaphore.
Semaphore(int n) Construct a Semaphore with the given counter value.

Method Summary

Modifier and Type	Method and Description
boolean	down() Perform a down() operation, as described above.
boolean	down(long timeout) Perform a down() operation, as described above.
void	up() Perform an up() operation, as described above.

Methods inherited from class java.lang.Object

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

Constructor Detail

Semaphore

public Semaphore()

Construct a Semaphore. The semaphore constructed has a counter value of zero.

Semaphore

public Semaphore(int n)

Construct a Semaphore with the given counter value.

Parameters:

n - - the initial value of the internal counter

Method Detail

down

public boolean down()
             throws InterruptedException

Perform a down() operation, as described above.

Throws:

InterruptedException

down

public boolean down(long timeout)
             throws InterruptedException

Perform a down() operation, as described above. This version takes an extra parameter which is a timeout. This method will return false if the operation timed out, true on success.

Throws:

InterruptedException

up

public void up()

Perform an up() operation, as described above.