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/*************************************************
*
* = PACKAGE
* JACE.Concurrency
*
* = FILENAME
* Semaphore.java
*
*@author Prashant Jain
*
*************************************************/
package JACE.Concurrency;
import java.util.*;
import JACE.ASX.*;
class TimedWaitSAdapter extends JACE.ASX.TimedWait
{
TimedWaitSAdapter (Object obj)
{
super (obj);
}
// Check to see if there are any semaphores available.
public boolean condition ()
{
return this.count_ > 0;
}
// Increment the count by one
public void increment ()
{
this.count_++;
}
// Decrement the count by one
public void decrement ()
{
this.count_--;
}
// Set the count
public void count (int c)
{
this.count_ = c;
}
private int count_ = 0;
}
/**
* <hr>
* <h2>SYNOPSIS</h2>
* Implementation of Dijkstra's counting semaphore in java.
*/
public class Semaphore
{
/**
* Create a Semaphore.
*@param count semaphore count
*/
public Semaphore (int c)
{
this.monitor_.count (c);
}
/**
* Acquire the Semaphore. Note that this will block.
*@exception InterruptedException exception during wait
*/
public synchronized void acquire () throws InterruptedException
{
this.monitor_.timedWait ();
this.monitor_.decrement ();
}
/**
* Acquire the Semaphore. Note that the call will return if <timeout>
* amount of time expires.
*@param tv amount of time (TimeValue) to wait before returning
* (unless operation completes before)
*@exception TimeoutException wait timed out exception
*@exception InterruptedException exception during wait
*/
public synchronized void acquire (TimeValue tv)
throws JACE.ASX.TimeoutException, InterruptedException
{
this.monitor_.timedWait (tv);
this.monitor_.decrement ();
}
/**
* Release the Semaphore.
*/
public synchronized void release ()
{
this.monitor_.increment ();
this.monitor_.signal ();
}
private TimedWaitSAdapter monitor_ = new TimedWaitSAdapter (this);
// The monitor (adapter) to wait on
}
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