code: @Override
      public Collection<PersonDocument> findByRootAndSurnameBeginsWith(
              final RootDocument rootDocument, final String beginsWith) {
          logger.debug("Starting findByRootAndSurnameBeginsWith");
          if (rootDocument == null) {
              return Collections.emptyList();
          }
          final Collection<PersonDocument> personDocuments =
                  findByFileAndSurnameBeginsWith(
                          rootDocument.getFilename(), beginsWith);
          for (final PersonDocument personDocument : personDocuments) {
              final Person person = personDocument.getGedObject();
              person.setParent(rootDocument.getGedObject());
          }
          logger.debug("Ending findByRootAndSurnameBeginsWith");
          return personDocuments;
      }
docs: {@inheritDoc}