/*
* The MIT License
*
* Copyright (c) 2010, InfraDNA, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package hudson.model.queue;
import hudson.AbortException;
/**
* A concurrency primitive that waits for N number of threads to synchronize.
* If any of the threads are interrupted while waiting for the completion of the condition,
* then all the involved threads get interrupted.
*
* @author Kohsuke Kawaguchi
*/
class Latch {
private final int n;
private int i=0;
/**
* If the synchronization on the latch is aborted/interrupted,
* point to the stack trace where that happened. If null,
* no interruption happened.
*/
private Exception interrupted;
public Latch(int n) {
this.n = n;
}
public synchronized void abort(Throwable cause) {
interrupted = new AbortException();
if (cause!=null)
interrupted.initCause(cause);
notifyAll();
}
public synchronized void synchronize() throws InterruptedException {
check(n);
try {
onCriteriaMet();
} catch (Error e) {
abort(e);
throw e;
} catch (RuntimeException e) {
abort(e);
throw e;
}
check(n*2);
}
private void check(int threshold) throws InterruptedException {
i++;
if (i==threshold) {
notifyAll();
} else {
while (i<threshold && interrupted==null) {
try {
wait();
} catch (InterruptedException e) {
interrupted = e;
notifyAll();
throw e;
}
}
}
// all of us either leave normally or get interrupted
if (interrupted!=null)
throw (InterruptedException)new InterruptedException().initCause(interrupted);
}
protected void onCriteriaMet() throws InterruptedException {}
}