code: @Override
      public final RootDocument findByFileAndString(
              final String filename, final String string) {
          final Query searchQuery = new Query(Criteria.where("string").is(string)
                  .and("filename").is(filename));
          final RootDocument rootDocument = mongoTemplate.findOne(searchQuery,
                  RootDocumentMongo.class);
          if (rootDocument == null) {
              return null;
          }
          final Root root =
                  (Root) toObjConverter.createRoot(rootDocument, finder);
          rootDocument.setGedObject(root);
          return rootDocument;
      }
docs: {@inheritDoc}