com.datastax.oss.driver.api.core.metadata

Interface NodeStateListener

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

NodeStateListenerBase

public interface NodeStateListener
extends AutoCloseable

A listener that gets notified when nodes states change.

An implementation of this interface can be registered in the configuration, or with SessionBuilder.withNodeStateListener(NodeStateListener).

Note that the methods defined by this interface will be executed by internal driver threads, and are therefore expected to have short execution times. If you need to perform long computations or blocking calls in response to schema change events, it is strongly recommended to schedule them asynchronously on a separate thread provided by your application code.

If you implement this interface but don't need to implement all the methods, extend NodeStateListenerBase.

Method Summary

Modifier and Type	Method and Description
void	onAdd(Node node) Invoked when a node is first added to the cluster.
void	onDown(Node node) Invoked when a node's state switches to NodeState.DOWN or NodeState.FORCED_DOWN.
void	onRemove(Node node) Invoked when a node leaves the cluster.
void	onUp(Node node) Invoked when a node's state switches to NodeState.UP.

Methods inherited from interface java.lang.AutoCloseable

close

Method Detail

onAdd

void onAdd(@NonNull
           Node node)

Invoked when a node is first added to the cluster.

The node is not up yet at this point. onUp(Node) will be notified later if the driver successfully connects to the node (provided that a session is opened and the node is not ignored), or receives a topology event for it.

This method is not invoked for the contact points provided at initialization. It is however for new nodes discovered during the full node list refresh after the first connection.

onUp

void onUp(@NonNull
          Node node)

Invoked when a node's state switches to NodeState.UP.

onDown

void onDown(@NonNull
            Node node)

Invoked when a node's state switches to NodeState.DOWN or NodeState.FORCED_DOWN.

onRemove

void onRemove(@NonNull
              Node node)

Invoked when a node leaves the cluster.

This can be triggered by a topology event, or during a full node list refresh if the node is absent from the new list.