/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program 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 for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Jul 10, 2008
*/
package com.bigdata.journal;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.locks.Lock;
import com.bigdata.concurrent.NamedLock;
/**
* An implementation using {@link NamedLock}s suitable for within JVM locking.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
*/
final
public class ResourceLockService implements IResourceLockService {
/**
* Table of locks. Locks are weakly held.
*
* @todo could use simple locks in weak value hash map with the name as the
* key.
*/
private final NamedLock<String/* namespace */> locks = new NamedLock<String>();
public ResourceLockService() {
}
@Override
public IResourceLock acquireLock(final String namespace) {
final Lock lock = locks.acquireLock(namespace);
return new ResourceLock(lock);
}
@Override
public IResourceLock acquireLock(final String namespace,
final long timeout) throws InterruptedException, TimeoutException {
final Lock lock = locks.acquireLock(namespace, timeout,
TimeUnit.MILLISECONDS);
return new ResourceLock(lock);
}
/**
* Inner class (NOT serializable).
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
private static final class ResourceLock implements IResourceLock {
private final Lock lock;
/**
*
* @param lock
* The lock (must have been acquired by the caller).
*/
protected ResourceLock(final Lock lock) {
if (lock == null)
throw new IllegalArgumentException();
this.lock = lock;
}
@Override
public void unlock() {
lock.unlock();
}
}
}