MysqlConnectionTester.java

/*
 Copyright  2002-2005 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.c3p0;

import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;

import com.mchange.v2.c3p0.C3P0ProxyConnection;
import com.mchange.v2.c3p0.QueryConnectionTester;
import com.mysql.jdbc.CommunicationsException;

/**
 * ConnectionTester for C3P0 connection pool that uses the more efficient
 * COM_PING method of testing connection 'liveness' for MySQL, and 'sorts'
 * exceptions based on SQLState or class of 'CommunicationsException' for
 * handling exceptions.
 * 
 * @version $Id: MysqlConnectionTester.java,v 1.1.2.1 2005/05/13 18:58:39
 *          mmatthews Exp $
 */
public final class MysqlConnectionTester implements QueryConnectionTester {

	private static final long serialVersionUID = 3256444690067896368L;

	private static final Object[] NO_ARGS_ARRAY = new Object[0];

	private Method pingMethod;

	public MysqlConnectionTester() {
		try {
			pingMethod = com.mysql.jdbc.Connection.class
					.getMethod("ping", null);
		} catch (Exception ex) {
			// punt, we have no way to recover, other than we now use 'SELECT 1'
			// for
			// handling the connection testing.
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see com.mchange.v2.c3p0.ConnectionTester#activeCheckConnection(java.sql.Connection)
	 */
	public int activeCheckConnection(Connection con) {
		try {
			if (pingMethod != null) {
				if (con instanceof com.mysql.jdbc.Connection) {
					// We've been passed an instance of a MySQL connection --
					// no need for reflection
					((com.mysql.jdbc.Connection) con).ping();
				} else {
					// Assume the connection is a C3P0 proxy
					C3P0ProxyConnection castCon = (C3P0ProxyConnection) con;
					castCon.rawConnectionOperation(pingMethod,
							C3P0ProxyConnection.RAW_CONNECTION, NO_ARGS_ARRAY);
				}
			} else {
				Statement pingStatement = null;

				try {
					pingStatement = con.createStatement();
					pingStatement.executeQuery("SELECT 1").close();
				} finally {
					if (pingStatement != null) {
						pingStatement.close();
					}
				}
			}

			return CONNECTION_IS_OKAY;
		} catch (Exception ex) {
			return CONNECTION_IS_INVALID;
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see com.mchange.v2.c3p0.ConnectionTester#statusOnException(java.sql.Connection,
	 *      java.lang.Throwable)
	 */
	public int statusOnException(Connection arg0, Throwable throwable) {
		if (throwable instanceof CommunicationsException
				|| "com.mysql.jdbc.exceptions.jdbc4.CommunicationsException"
						.equals(throwable.getClass().getName())) {
			return CONNECTION_IS_INVALID;
		}

		if (throwable instanceof SQLException) {
			String sqlState = ((SQLException) throwable).getSQLState();

			if (sqlState != null && sqlState.startsWith("08")) {
				return CONNECTION_IS_INVALID;
			}

			return CONNECTION_IS_OKAY;
		}

		// Runtime/Unchecked?

		return CONNECTION_IS_INVALID;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see com.mchange.v2.c3p0.QueryConnectionTester#activeCheckConnection(java.sql.Connection,
	 *      java.lang.String)
	 */
	public int activeCheckConnection(Connection arg0, String arg1) {
		return CONNECTION_IS_OKAY;
	}
}