private void checkInvalidTopology(boolean errorCondition, String errorMessageTemplate, Object... errorMessageParams) throws InvalidTopologyException {
    if (errorCondition) throw new InvalidTopologyException(String.format(errorMessageTemplate, errorMessageParams));
  }
Verifies that all respective properties are set for an external NANENODE HA setup
ambari-server/src/main/java/org/apache/ambari/server/topology/validators/NameNodeHaValidator.java