com.sleepycat.je.rep
Interface StateChangeListener

public interface StateChangeListener

An asynchronous mechanism for tracking the State of the replicated environment and choosing how to route database operations. State determines which operations are currently permitted on the node. For example, only the MASTER node can execute write operations.

The Listener is registered with the replicated environment using ReplicatedEnvironment.setStateChangeListener(StateChangeListener). There is at most one Listener associated with the actual environment (not an Environment handle) at any given instance in time.

See the examples for information on different approaches toward routing database operations and an example of using the StateChangeListener.

See Also:

Managing Write Requests at a Replica

Method Summary

void	stateChange(StateChangeEvent stateChangeEvent) The notification method.

Method Detail

stateChange

void stateChange(StateChangeEvent stateChangeEvent)
                 throws RuntimeException

The notification method. It is initially invoked when the StateChangeListener is first associated with the ReplicatedEnvironment via the ReplicatedEnvironment.setStateChangeListener(StateChangeListener) method and subsequently each time there is a state change.

This method should do the minimal amount of work, queuing any resource intensive operations for processing by another thread before returning to the caller, so that it does not unduly delay the other housekeeping operations performed by the internal thread which invokes this method.

Parameters:

stateChangeEvent - the new state change event

Throws:

RuntimeException - Any uncaught exceptions will result in the shutdown of the ReplicatedEnvironment.