/*
*
* * Copyright 2014 Orient Technologies LTD (info(at)orientechnologies.com)
* *
* * Licensed 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.
* *
* * For more information: http://www.orientechnologies.com
*
*/
package com.orientechnologies.common.concur.resource;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import com.orientechnologies.common.concur.OTimeoutException;
/**
* Shared resource. Sub classes can acquire and release shared and exclusive locks.
*
* @author Luca Garulli (l.garulli--at--orientechnologies.com)
*
*/
public abstract class OSharedResourceTimeout {
private final ReadWriteLock lock = new ReentrantReadWriteLock();
protected int timeout;
public OSharedResourceTimeout(final int timeout) {
this.timeout = timeout;
}
protected void acquireSharedLock() throws OTimeoutException {
try {
if (timeout == 0) {
lock.readLock().lock();
return;
} else if (lock.readLock().tryLock(timeout, TimeUnit.MILLISECONDS))
// OK
return;
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
throw new OTimeoutException("Timeout on acquiring shared lock against resource: " + this);
}
protected void releaseSharedLock() {
lock.readLock().unlock();
}
protected void acquireExclusiveLock() throws OTimeoutException {
try {
if (timeout == 0) {
lock.writeLock().lock();
return;
} else if (lock.writeLock().tryLock(timeout, TimeUnit.MILLISECONDS))
// OK
return;
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
throw new OTimeoutException("Timeout on acquiring exclusive lock against resource: " + this);
}
protected void releaseExclusiveLock() {
lock.writeLock().unlock();
}
}