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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 $
 */
00044 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;
      }
}

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