@Override
  public ResourceInstance createResource(Resource.Type type, Map<Resource.Type, String> mapIds) {

    // this code changes hot name to lower case
    try {
      if (mapIds.containsKey(Resource.Type.Host)) {
        String hostName = mapIds.get(Resource.Type.Host);
        if (hostName != null) {
          mapIds.put(Resource.Type.Host, hostName.toLowerCase());
        }
      }
    } catch(Exception e) {
      LOG.error("Lowercase host name value in resource failed with error:" + e);
    }

    ResourceDefinition resourceDefinition = getResourceDefinition(type, mapIds);

    return new QueryImpl(mapIds, resourceDefinition, ClusterControllerHelper.getClusterController());
  }
Map of external resource definitions (added through views).
ambari-server/src/main/java/org/apache/ambari/server/api/resources/ResourceInstanceFactoryImpl.java