Interface BalanceStrategy

All Superinterfaces:

Extension

All Known Implementing Classes:

BestResponseTimeBalanceStrategy, RandomBalanceStrategy, SequentialBalanceStrategy, ServerAffinityStrategy

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

Modifier and Type	Method	Description
ConnectionImpl	pickConnection(LoadBalancedConnectionProxy proxy, List<String> configuredHosts, Map<String, ConnectionImpl> liveConnections, long[] responseTimes, int numRetries)	Called by the driver to pick a new connection to route requests over.

Methods inherited from interface Extension

destroy, init

Method Details

pickConnection

ConnectionImpl pickConnection(LoadBalancedConnectionProxy proxy,
 List<String> configuredHosts,
 Map<String, ConnectionImpl> liveConnections,
 long[] responseTimes,
 int numRetries)
                       throws 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:

SQLException - if a new connection can not be found or created by this strategy.

See Also:

• LoadBalancedConnectionProxy.createConnectionForHost(String)