ReleaseLockCommand.java

/*
 * HA-JDBC: High-Availability JDBC
 * Copyright (C) 2012  Paul Ferraro
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package net.sf.hajdbc.lock.distributed;

import java.util.Map;
import java.util.concurrent.locks.Lock;

import net.sf.hajdbc.distributed.Command;

/**
 * Release lock command for execution on group member.
 * @author Paul Ferraro
 */
public class ReleaseLockCommand implements Command<Void, LockCommandContext>
{
	private static final long serialVersionUID = -4088487420468046409L;

	private final RemoteLockDescriptor descriptor;
	
	public ReleaseLockCommand(RemoteLockDescriptor descriptor)
	{
		this.descriptor = descriptor;
	}

	/**
	 * {@inheritDoc}
	 * @see net.sf.hajdbc.distributed.Command#execute(java.lang.Object)
	 */
	@Override
	public Void execute(LockCommandContext context)
	{
		Map<LockDescriptor, Lock> locks = context.getRemoteLocks(this.descriptor);
		
		if (locks != null)
		{
			Lock lock = null;
			
			synchronized (locks)
			{
				lock = locks.remove(this.descriptor);
			}
			
			if (lock != null)
			{
				lock.unlock();
			}
		}

		return null;
	}

	/**
	 * {@inheritDoc}
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString()
	{
		return String.format("%s(%s)", this.getClass().getSimpleName(), this.descriptor);
	}
}