private JSONObject readFromCluster(String url) throws AmbariHttpException {
    String response = ambariApi.requestClusterAPI(url);
    if (response == null || response.isEmpty()) {
      return null;
    }

    return getJsonObject(response);
  }
Checks if the user is an operator.

@return    if <code>true</code>, the user is an operator; otherwise <code>false</code>
contrib/views/capacity-scheduler/src/main/java/org/apache/ambari/view/capacityscheduler/ConfigurationService.java