/*
* Copyright 2010 Red Hat, Inc.
*
* Red Hat licenses this file to you under the Apache License, version 2.0
* (the "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package org.jboss.netty.util.internal;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
/**
* @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
* @author <a href="http://gleamynode.net/">Trustin Lee</a>
* @version $Rev: 2115 $, $Date: 2010-02-01 15:21:49 +0900 (Mon, 01 Feb 2010) $
*/
public final class NonReentrantLock extends AbstractQueuedSynchronizer
implements Lock {
//private static final long serialVersionUID = 1L;
private Thread owner;
public void lock() {
acquire(1);
}
public void lockInterruptibly() throws InterruptedException {
acquireInterruptibly(1);
}
public boolean tryLock() {
return tryAcquire(1);
}
public boolean tryLock(long time, TimeUnit unit)
throws InterruptedException {
return tryAcquireNanos(1, unit.toNanos(time));
}
public void unlock() {
release(1);
}
public boolean isHeldByCurrentThread() {
return isHeldExclusively();
}
public Condition newCondition() {
return new ConditionObject();
}
@Override
protected final boolean tryAcquire(int acquires) {
if (compareAndSetState(0, 1)) {
owner = Thread.currentThread();
return true;
}
return false;
}
@Override
protected final boolean tryRelease(int releases) {
if (Thread.currentThread() != owner) {
throw new IllegalMonitorStateException();
}
owner = null;
setState(0);
return true;
}
@Override
protected final boolean isHeldExclusively() {
return getState() != 0 && owner == Thread.currentThread();
}
}