Package org.apache.activemq.artemis.api.core.client

## Interface ClusterTopologyListener

-     public interface ClusterTopologyListener

  A cluster topology listener.

  Used to get notification of topology events. After adding a listener to the cluster connection, the listener receives `nodeUP(TopologyMember, boolean)` for all the current topology members.

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `nodeDown​(long eventUID, java.lang.String nodeID)` | Triggered when a node leaves the cluster.
    `void` | `nodeUP​(TopologyMember member, boolean last)` | Triggered when a node joins the cluster.

- - ### Method Detail

    - #### nodeUP

          void nodeUP​(TopologyMember member,
                      boolean last)

      Triggered when a node joins the cluster.
      Parameters:
        `member` -
        `last` - if the whole cluster topology is being transmitted (after adding the listener to the cluster connection) this parameter will be `true` for the last topology member.

    - #### nodeDown

          void nodeDown​(long eventUID,
                        java.lang.String nodeID)

      Triggered when a node leaves the cluster.
      Parameters:
        `eventUID` -
        `nodeID` - the id of the node leaving the cluster