Logo Search packages:      
Sourcecode: mysql-connector-java version File versions  Download package

BalanceStrategy.java

/*
  Copyright (c) 2007, 2010, 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;

import java.sql.SQLException;
import java.util.List;
import java.util.Map;

/**
 * Implement this interface to provide a new load balancing strategy for URLs of
 * the form "jdbc:mysql:loadbalance://..", and provide the implementation class
 * name as the configuration parameter "loadBalanceStrategy".
 * 
 * The driver will not pass in a Connection instance when calling init(), but it
 * will pass in the Properties, otherwise it acts like a normal Extension.
 * 
 * One instance of a strategy *per* JDBC connection instance will be created. If
 * you need singleton-like behavior, you're on your own to provide it.
 */
00040 public interface BalanceStrategy extends Extension {
      /**
       * Called by the driver to pick a new connection to route requests over.
       * 
       * @param proxy
       *            the InvocationHandler that deals with actual method calls to
       *            the JDBC connection, and serves as a factory for new
       *            connections for this strategy via the
       *            createConnectionForHost() method.
       * 
       * This proxy takes care of maintaining the response time list, map of
       * host/ports to live connections, and taking connections out of the live
       * connections map if they receive a network-related error while they are in
       * use by the application.
       * @param configuredHosts
       *            the list of hosts/ports (in "host:port" form) as passed in by
       *            the user.
       * @param liveConnections
       *            a map of host/ports to "live" connections to them.
       * @param responseTimes
       *            the list of response times for a <strong>transaction</strong>
       *            for each host in the configured hosts list.
       * @param numRetries
       *            the number of times the driver expects this strategy to re-try
       *            connection attempts if creating a new connection fails.
       * @return the physical JDBC connection for the application to use, based
       *         upon the strategy employed.
       * @throws SQLException
       *             if a new connection can not be found or created by this
       *             strategy.
       * 
       * @see LoadBalancingConnectionProxy#createConnectionForHost(String)
       */
      public abstract ConnectionImpl pickConnection(
                  LoadBalancingConnectionProxy proxy, List<String> configuredHosts,
                  Map<String, ConnectionImpl> liveConnections, long[] responseTimes, int numRetries)
                  throws SQLException;
}

Generated by  Doxygen 1.6.0   Back to index