/**
   * {@inheritDoc}
   *
   * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest,
   *     javax.servlet.http.HttpServletResponse)
   */
  @Override
  @edu.umd.cs.findbugs.annotations.SuppressWarnings(
      value = "BC_VACUOUS_INSTANCEOF",
      justification = "Could be injected from annother bundle")
  protected void doGet(HttpServletRequest req, HttpServletResponse resp)
      throws ServletException, IOException {

    if (trustedTokenService instanceof TrustedTokenServiceImpl) {
      final AuthenticatedAction authAction = new AuthenticatedAction();
      ((TrustedTokenServiceImpl) trustedTokenService)
          .injectToken(
              req,
              resp,
              TrustedTokenTypes.AUTHENTICATED_TRUST,
              new UserValidator() {

                public String validate(String userId) {
                  if (userId != null) {
                    // we found a user, check if it really exists.
                    Session session = null;
                    try {
                      session = repository.loginAdministrative();
                      AuthorizableManager am = session.getAuthorizableManager();
                      Authorizable a = am.findAuthorizable(userId);
                      if (a == null) {
                        LOGGER.info("Authenticated User {} does not exist");
                        authAction.setAction(AuthenticatedAction.REDIRECT);
                        return null;
                      }
                    } catch (Exception e) {
                      LOGGER.warn("Failed to check user ", e);
                    } finally {
                      if (session != null) {
                        try {
                          session.logout();
                        } catch (ClientPoolException e) {
                          LOGGER.warn("Failed to close admin session ", e);
                        }
                      }
                    }
                  }
                  return userId;
                }
              });
      String destination = req.getParameter(PARAM_DESTINATION);
      if (destination == null) {
        destination = defaultDestination;
      }
      if (authAction.isRedirect()) {
        String redirectLocation =
            MessageFormat.format(
                noUserRedirectLocationFormat, URLEncoder.encode(destination, "UTF-8"));
        resp.sendRedirect(redirectLocation);
      } else {
        if (destination == null) {
          destination = defaultDestination;
        }
        // ensure that the redirect is safe and not susceptible to
        resp.sendRedirect(destination.replace('\n', ' ').replace('\r', ' '));
      }
    } else {
      LOGGER.debug(
          "Trusted Token Service is not the correct implementation and so cant inject tokens. ");
    }
  }