/*
* Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @bug 4530538
* @summary A Barrier utility class.
* @author Mandy Chung
*/
public class Barrier {
private Object go = new Object();
private int count;
private int waiters = 0;
public Barrier(int count) {
if (count <= 0) {
throw new IllegalArgumentException();
}
this.count = count;
}
public void set(int count) {
if (waiters != 0) {
throw new IllegalArgumentException();
}
this.count = count;
this.waiters = 0;
}
public void await() {
synchronized (go) {
waiters++;
while (count > 0) {
try {
go.wait();
} catch (InterruptedException e) {
e.printStackTrace();
throw new InternalError();
}
}
waiters--;
}
}
public void signal() {
synchronized (go) {
count--;
go.notifyAll();
}
}
public int getWaiterCount() {
synchronized (go) {
return waiters;
}
}
}