throws ParserConfigurationException, SAXException, IOException, JspTagException {
ProxyTicketValidator pv = new ProxyTicketValidator();
pv.setCasValidateUrl(casValidate);
pv.setServiceTicket(ticket);
pv.setService(service);
pv.validate();
if (!pv.isAuthenticationSuccesful())
throw new JspTagException(
"CAS authentication error: " + pv.getErrorCode());
if (pv.getProxyList().size() != 0) {
// ticket was proxied