code: public static String getReqAttrVal(final Element el, final String name)
        throws SAXException {
      String str = getAttrVal(el, name);
  
      if ((str == null) || (str.length() == 0)) {
        throw new SAXException("Missing attribute value: " + name);
      }
  
      return str;
    }
docs: Return the required value of the named attribute of the given element.
  
  @param el          Element
  @param name        String name of desired attribute
  @return String     attribute value
  @throws SAXException