You can register a callback handler for a multi data source with WebLogic Server that controls when a multi data source with the Failover algorithm fails over to the next data source in the data source list. You can use callback handlers to control if or when the failover occurs so that you can make any other system preparations before the failover, such as priming a database or communicating with a high-availability framework. For more information, see Controlling Multi Data Source Failover with a Callback.
To register a failover callback handler for a JDBC multi data source:
The failover callback handler must implement the weblogic.jdbc.extensions.ConnectionPoolFailoverCallback interface.