code: @Override
      public void start() {
          super.start();
  
          if (hasOption(SHORT_OPT_IN_PATH)) {
              processInputDirectories();
          } else if (hasOption(INFILE_SHORT_OPT)) {
              processFiles();
          } else {
              error(NO_XBEL_INPUT);
              failUsage();
          }
      }
docs: {@inheritDoc}