code: public static void setPrivateAttribute(HttpServletRequest req, String key, Object object) {
          HttpServletRequest sr = getWrappedServletRequestObject(req);
          if (sr instanceof IPrivateRequestAttributes) {
              ((IPrivateRequestAttributes) sr).setPrivateAttribute(key, object);
          } else {
              if (tc.isDebugEnabled()) {
                  Tr.debug(tc, "getPrivateAttribute called for non-IPrivateRequestAttributes object", req);
              }
          }
      }
docs: Set a private attribute in the request (if applicable).
  If the request object is of an unexpected type, no operation occurs.
  
  @param req
  @param key
  @param object
  @see IPrivateRequestAttributes#setPrivateAttribute(String, Object)