code: private static ConfigurationModule addAll(final ConfigurationModule conf,
                                              final OptionalParameter<String> param,
                                              final File folder) {
      ConfigurationModule result = conf;
      final File[] files = folder.listFiles();
      if (files != null) {
        for (final File f : files) {
          if (f.canRead() && f.exists() && f.isFile()) {
            result = result.set(param, f.getAbsolutePath());
          }
        }
      }
      return result;
    }
docs: 1000 sec.