@Override
  public RequestStatus updateResources(Request request, Predicate predicate)
      throws SystemException, UnsupportedPropertyException,
      NoSuchResourceException, NoSuchParentResourceException {

    Iterator<Map<String,Object>> iterator = request.getProperties().iterator();
    if (iterator.hasNext()) {

      Map<String,Object> updateProperties = iterator.next();

      List<StageEntity> entities = dao.findAll(request, predicate);
      for (StageEntity entity : entities) {

        String stageStatus = (String) updateProperties.get(STAGE_STATUS);
        if (stageStatus != null) {
          HostRoleStatus desiredStatus = HostRoleStatus.valueOf(stageStatus);
          dao.updateStageStatus(entity, desiredStatus,
              getManagementController().getActionManager());
        }
      }
    }
    notifyUpdate(Resource.Type.Stage, request, predicate);

    return getRequestStatus(null);
  }
Constructor.

@param managementController  the Ambari management controller
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/StageResourceProvider.java