code: public static String getOneNodeVal(final Node el, final String name)
        throws SAXException {
      /* We expect one child of type text */
  
      if (!el.hasChildNodes()) {
        return null;
      }
  
      NodeList children = el.getChildNodes();
      if (children.getLength() > 1){
        throw new SAXException("Multiple property values: " + name);
      }
  
      Node child = children.item(0);
      return child.getNodeValue();
    }
docs: Get the value of an element. We expect 0 or 1 child nodes.
  For no child node we return null, for more than one we raise an
  exception.
  
  @param el          Node whose value we want
  @param name        String name to make exception messages more readable
  @return String     node value or null
  @throws SAXException