com.mysql.jdbc.BalanceStrategy Maven / Gradle / Ivy
/*
Copyright (c) 2007, 2014, Oracle and/or its affiliates. All rights reserved.
The MySQL Connector/J is licensed under the terms of the GPLv2
, 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
.
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.
*/
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 transaction
* 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 configuredHosts,
Map liveConnections, long[] responseTimes, int numRetries) throws SQLException;
}