The Membership Listener interface has methods that are invoked for the following events.
memberAdded
: A new member is added to the cluster.memberRemoved
: An existing member leaves the cluster.memberAttributeChanged
: An attribute of a member is changed. Please refer to Defining Member Attributes to learn about member attributes.To write a Membership Listener class, you implement the MembershipListener interface and its methods.
The following is an example Membership Listener class.
public class ClusterMembershipListener
implements MembershipListener {
public void memberAdded(MembershipEvent membershipEvent) {
System.err.println("Added: " + membershipEvent);
}
public void memberRemoved(MembershipEvent membershipEvent) {
System.err.println("Removed: " + membershipEvent);
}
public void memberAttributeChanged(MemberAttributeEvent memberAttributeEvent) {
System.err.println("Member attribute changed: " + memberAttributeEvent);
}
}
When a respective event is fired, the membership listener outputs the addresses of the members that joined and left, and also which attribute changed on which member.