private ServiceComponent getServiceComponent ( ActionExecutionContext actionExecutionContext,
                                                RequestResourceFilter resourceFilter){
    try {
      Cluster cluster = clusters.getCluster(actionExecutionContext.getClusterName());
      Service service = cluster.getService(resourceFilter.getServiceName());

      return service.getServiceComponent(resourceFilter.getComponentName());
    } catch (Exception e) {
      LOG.debug("Unknown error appears during getting service component: {}", e.getMessage());
    }
    return null;
  }
Determine whether or not the action should trigger a topology refresh.

@param actionName   the action name (i.e. START, RESTART)
@param clusterName  the cluster name
@param serviceName  the service name

@return true if a topology refresh is required for the action
ambari-server/src/main/java/org/apache/ambari/server/controller/AmbariCustomCommandExecutionHelper.java