@Override
  public void addSessionAttributes(Map<String, Object> attributes) {
    if (attributes != null && !attributes.isEmpty()) {
      Map<String, Object>  sessionAttributes = new HashMap<>(getSessionAttributes());
      sessionAttributes.putAll(attributes);
      setSessionAttributes(attributes);
    }
  }
@param serviceName name of the service
@param componentName name of the component
@return the set of hosts for the provided service and component
ambari-server/src/main/java/org/apache/ambari/server/state/cluster/ClusterImpl.java