MysqlConnectionTester.java

/*
 Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
 

  The MySQL Connector/J is licensed under the terms of the GPLv2
  <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most MySQL Connectors.
  There are special exceptions to the terms and conditions of the GPLv2 as it is applied to
  this software, see the FLOSS License Exception
  <http://www.mysql.com/about/legal/licensing/foss-exception.html>.

  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 transient Method pingMethod;

	public MysqlConnectionTester() {
		try {
			pingMethod = com.mysql.jdbc.Connection.class
					.getMethod("ping", (Class[])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;
	}
}