code: public String getAuthType()
      {
          String at= _httpRequest.getAuthType();
          if (at==SecurityConstraint.__BASIC_AUTH)
              return HttpServletRequest.BASIC_AUTH;
          if (at==SecurityConstraint.__FORM_AUTH)
              return HttpServletRequest.FORM_AUTH;
          if (at==SecurityConstraint.__DIGEST_AUTH)
              return HttpServletRequest.DIGEST_AUTH;
          if (at==SecurityConstraint.__CERT_AUTH)
              return HttpServletRequest.CLIENT_CERT_AUTH;
          if (at==SecurityConstraint.__CERT_AUTH2)
              return HttpServletRequest.CLIENT_CERT_AUTH;
          return at;
      }
docs: /* ------------------------------------------------------------