code: String concatIndentAndDirectoryName(String indent, File directory) {
  
      indent = Optional.ofNullable(indent).filter(StringUtils::hasText)
        .map(it -> it + SUB_DIRECTORY_DASH_PLUS_OFFSET)
        .orElse(StringUtils.EMPTY_STRING);
  
      return String.format(indent + DIRECTORY_MARKER_WITH_DIRECTORY_NAME, directory.getName());
    }
docs: /* (non-Javadoc)