@Override
    public Collection<String> getRequiredHostGroups(String propertyName,
                                                    String origValue,
                                                    Map<String, Map<String, String>> properties,
                                                    ClusterTopology topology) {
      return Collections.emptyList();
    }
A topology independent updater which provides a default implementation of getRequiredHostGroups
since no topology related information is required by the updater.
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/BlueprintConfigurationProcessor.java