private ServiceComponent getServiceComponent(String clusterName, String serviceName, String componentName)
      throws AmbariException {

    Clusters clusters = getManagementController().getClusters();
    return clusters.getCluster(clusterName).getService(serviceName).getServiceComponent(componentName);
  }
Checks if assigning new state does not require performing
any additional actions
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/HostComponentResourceProvider.java