+
+ 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"
+ );
+