com.mysql.jdbc
Interface BalanceStrategy

All Superinterfaces:
Extension
All Known Implementing Classes:
BestResponseTimeBalanceStrategy, RandomBalanceStrategy

public interface BalanceStrategy
extends Extension

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.


Method Summary
 Connection pickConnection(LoadBalancingConnectionProxy proxy, java.util.List configuredHosts, java.util.Map liveConnections, long[] responseTimes, int numRetries)
          Called by the driver to pick a new connection to route requests over.
 
Methods inherited from interface com.mysql.jdbc.Extension
destroy, init
 

Method Detail

pickConnection

Connection pickConnection(LoadBalancingConnectionProxy proxy,
                          java.util.List configuredHosts,
                          java.util.Map liveConnections,
                          long[] responseTimes,
                          int numRetries)
                          throws java.sql.SQLException
Called by the driver to pick a new connection to route requests over.

Parameters:
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.
configuredHosts - the list of hosts/ports (in "host:port" form) as passed in by the user.
liveConnections - a map of host/ports to "live" connections to them.
responseTimes - the list of response times for a transaction for each host in the configured hosts list.
numRetries - the number of times the driver expects this strategy to re-try connection attempts if creating a new connection fails.
Returns:
the physical JDBC connection for the application to use, based upon the strategy employed.
Throws:
java.sql.SQLException - if a new connection can not be found or created by this strategy.
See Also:
LoadBalancingConnectionProxy.createConnectionForHost(String)