@Override
  public Backend.Session open(Class<?> entityType) {
    final String index = resolver.resolve(entityType);
    return new Session(entityType, keyExtractorFactory.create(entityType), new ElasticsearchOps(restClient, index, objectMapper, scrollSize), pathNaming);
  }
Queries <a href="https://www.elastic.co/">ElasticSearch</a> data-store.
criteria/elasticsearch/src/org/immutables/criteria/elasticsearch/ElasticsearchBackend.java