import akka.actor.ActorSystem;
import akka.cluster.Cluster;
import akka.cluster.ClusterEvent;
+import com.google.common.base.Preconditions;
public class ClusterWrapperImpl implements ClusterWrapper {
private final Cluster cluster;
private final String currentMemberName;
public ClusterWrapperImpl(ActorSystem actorSystem){
+ Preconditions.checkNotNull(actorSystem, "actorSystem should not be null");
+
cluster = Cluster.get(actorSystem);
+
+ Preconditions.checkState(cluster.getSelfRoles().size() > 0,
+ "No akka roles were specified\n" +
+ "One way to specify the member name is to pass a property on the command line like so\n" +
+ " -Dakka.cluster.roles.0=member-3\n" +
+ "member-3 here would be the name of the member"
+ );
+
currentMemberName = (String) cluster.getSelfRoles().toArray()[0];
}
public void subscribeToMemberEvents(ActorRef actorRef){
+ Preconditions.checkNotNull(actorRef, "actorRef should not be null");
+
cluster.subscribe(actorRef, ClusterEvent.initialStateAsEvents(),
ClusterEvent.MemberEvent.class,
ClusterEvent.UnreachableMember.class);