MysqlValidConnectionChecker.java

/*
 Copyright  2002-2006 MySQL AB, 2008 Sun Microsystems
 All rights reserved. Use is subject to license terms.

  The MySQL Connector/J is licensed under the terms of the GPL,
  like most MySQL Connectors. There are special exceptions to the
  terms and conditions of the GPL as it is applied to this software,
  see the FLOSS License Exception available on mysql.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., 51 Franklin St, Fifth Floor, Boston, MA
  02110-1301 USA
 */

package com.mysql.jdbc.integration.jboss;

import java.io.Serializable;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;

import org.jboss.resource.adapter.jdbc.ValidConnectionChecker;

/**
 * A more efficient connection checker for JBoss.
 * 
 * @version $Id: MysqlValidConnectionChecker.java,v 1.1.2.1 2005/05/13 18:58:42
 *          mmatthews Exp $
 */
public final class MysqlValidConnectionChecker implements
		ValidConnectionChecker, Serializable {

	private static final long serialVersionUID = 8909421133577519177L;

	public MysqlValidConnectionChecker() {
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.jboss.resource.adapter.jdbc.ValidConnectionChecker#isValidConnection(java.sql.Connection)
	 */
	public SQLException isValidConnection(Connection conn) {

		// Use "/* ping */ SELECT 1" which will send
		// pings across multi-connections too in case the connection
		// was "wrapped" by Jboss in any way...

		Statement pingStatement = null;

		try {
			pingStatement = conn.createStatement();
			
			pingStatement.executeQuery("/* ping */ SELECT 1").close();

			return null;
		} catch (SQLException sqlEx) {
			return sqlEx;
		} finally {
			if (pingStatement != null) {
				try {
					pingStatement.close();
				} catch (SQLException sqlEx) {
					// can't do anything about it here
				}
			}
		}
	}
}