private boolean isTargetHostTypeAllowsEmptyHosts(TargetHostType targetHostType) {
    return targetHostType.equals(TargetHostType.ALL) || targetHostType.equals(TargetHostType.ANY)
            || targetHostType.equals(TargetHostType.MAJORITY);
  }
Validates the request to execute an action.
@param actionRequest
@throws AmbariException
ambari-server/src/main/java/org/apache/ambari/server/controller/AmbariActionExecutionHelper.java