code: public ModelAndView getRule(long id) {
          Rule rule = ruleDao.getRule(id);
  
          if (rule == null) {
              return new ModelAndView(view, "object", new SimpleError("Rule "
                      + id + " does not exist.", 404));
          }
  
          return new ModelAndView(view, "object", rule);
      }
docs: GET /rules/:id
  
  Retrieves the rule with the given id.
  
  @param id
  @return