/**
  * List users.
  *
  * <p>GET /api/user/?userType&userStates&pageNumber&itemsPerPage
  */
 @RequestMapping(
     value = {"/", ""},
     method = RequestMethod.GET,
     params = {"userType", "userStates"})
 public Page<User> userList(
     UserAuthentication userAuthentication,
     @RequestParam Character userType,
     @RequestParam String userStates,
     @RequestParam(defaultValue = "1") Integer pageNumber,
     @RequestParam(defaultValue = "20") Integer itemsPerPage) {
   Page<User> userList =
       new PageDecorator<User>(
           userQueryService.userList(
               userAuthentication.getEntityId(),
               userType,
               userStates,
               pageNumber - 1,
               itemsPerPage));
   return userList;
 }