@Override
  public final Object getDocument(String url) throws FunctionCallException {
    SAXBuilder sb = new SAXBuilder();
    try {
      return sb.build(url);
    }
    catch (JDOMException e) {
      throw new FunctionCallException("Failed to parse " + url, e);
    }
    catch (IOException e) {
      throw new FunctionCallException("Failed to access " + url, e);
    }
  }
@Override
  public final Object getDocument(String url)