/* -*- tab-width: 4 -*-
*
* Electric(tm) VLSI Design System
*
* File: SenseBarrier.java
*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
*
* Electric(tm) is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* Electric(tm) is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Electric(tm); see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, Mass 02111-1307, USA.
*/
package com.sun.electric.tool.util.concurrent.barriers;
import java.util.concurrent.atomic.AtomicInteger;
/**
* @author fs239085
*
*/
public class SenseBarrier implements Barrier {
private AtomicInteger count;
private int size;
private Boolean sense;
private ThreadLocal<Boolean> threadSense;
public SenseBarrier(int n) {
count = new AtomicInteger(n);
size = n;
sense = false;
threadSense = new ThreadLocal<Boolean>() {
/*
* (non-Javadoc)
*
* @see java.lang.ThreadLocal#initialValue()
*/
@Override
protected Boolean initialValue() {
return !sense;
}
};
}
/*
* (non-Javadoc)
*
* @see com.sun.electric.tool.util.concurrent.barriers.Barrier#await()
*/
public void await() {
Boolean mySense = threadSense.get();
int position = count.getAndDecrement();
if (position == 1) {
count.set(size);
sense = mySense;
} else {
while (sense != mySense) {}
}
threadSense.set(!mySense);
}
}