/**
  * Modifies a given TestElement to mirror the data in the gui components.
  *
  * @see org.apache.jmeter.gui.JMeterGUIComponent#modifyTestElement(TestElement)
  */
 public void modifyTestElement(TestElement el) {
   super.configureTestElement(el);
   if (el instanceof XPathAssertion) {
     XPathAssertion assertion = (XPathAssertion) el;
     assertion.setNegated(xpath.isNegated());
     assertion.setXPathString(xpath.getXPath());
     xml.modifyTestElement(assertion);
   }
 }
  @Override
  public void configure(TestElement el) {
    super.configure(el);
    XPathAssertion assertion = (XPathAssertion) el;
    xpath.setXPath(assertion.getXPathString());
    xpath.setNegated(assertion.isNegated());

    xml.configure(assertion);
  }