docs: @Override
    public String getValueAsString() {
      StringBuilder buf = new StringBuilder();
      List<File> val = getValue();
      Iterator<File> veciter = val.iterator();
      while(veciter.hasNext()) {
        buf.append(veciter.next());
        if(veciter.hasNext()) {
          buf.append(LIST_SEP);
        }
      }
      return buf.toString();
    }