org.codehaus.groovy.util.LockableObject Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of groovy-all Show documentation
Show all versions of groovy-all Show documentation
Groovy: A powerful, dynamic language for the JVM
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.codehaus.groovy.util;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
/**
* A bit simplified lock designed to be inherited by.
*/
public class LockableObject extends AbstractQueuedSynchronizer {
transient Thread owner;
protected final boolean isHeldExclusively() {
return getState() != 0 && owner == Thread.currentThread();
}
public final void lock() {
if (compareAndSetState(0, 1))
owner = Thread.currentThread();
else
acquire(1);
}
public final void unlock() {
release(1);
}
protected final boolean tryAcquire(int acquires) {
final Thread current = Thread.currentThread();
int c = getState();
if (c == 0) {
if (compareAndSetState(0, acquires)) {
owner = current;
return true;
}
}
else if (current == owner) {
setState(c+ acquires);
return true;
}
return false;
}
protected final boolean tryRelease(int releases) {
int c = getState() - releases;
if (Thread.currentThread() != owner)
throw new IllegalMonitorStateException();
boolean free = false;
if (c == 0) {
free = true;
owner = null;
}
setState(c);
return free;
}
}