code: @Override
      public final TrailerDocument findByFileAndString(
              final String filename, final String string) {
          final Query searchQuery = new Query(Criteria.where("string").is(string)
                  .and("filename").is(filename));
          final TrailerDocument trailerDocument =
                  mongoTemplate.findOne(searchQuery, TrailerDocumentMongo.class);
          if (trailerDocument == null) {
              return null;
          }
          final Trailer trailer = (Trailer) toObjConverter.createGedObject(
                  null, trailerDocument);
          trailerDocument.setGedObject(trailer);
          return trailerDocument;
      }
docs: {@inheritDoc}