/**
  * delete
  *
  * @param req a {@link javax.servlet.http.HttpServletRequest} object.
  * @return a {@link org.springframework.web.servlet.ModelAndView} object.
  */
 @RequestMapping("/group.delete.page")
 public ModelAndView delete(HttpServletRequest req) {
   Group group = WebUtils.getGroup(req);
   ModelAndView mav = new ModelAndView(Constants.REDIRECT_GROUP_LIST);
   mav.addObject(
       Constants.MESSAGE,
       group.remove()
           ? Constants.MSG_AUTHORITY_DELETE_SUCCESS
           : Constants.MSG_AUTHORITY_DELETE_FAILURE);
   return mav;
 }