private Result getRoleList(Screen.Button button) {
   Result result;
   Screen next;
   List<Role> roleList = new ArrayList<Role>();
   result = listAllRoles(roleList);
   if (result.isSuccessful()) {
     next = new Screen(this, button.destination());
     next.setValue(Screen.AVAILABLE_ROLES, roleList);
     result.objectValue(next);
   } else {
     log(result.getReason().name());
     log(result.allMessages());
   }
   return result;
 }
 private Result getUserList(Screen.Button button) {
   Result result;
   Screen next;
   List<User> userList = new ArrayList<User>();
   result = listUsers(userList);
   if (result.isSuccessful()) {
     next = new Screen(this, button.destination());
     next.setValue(Screen.USERS_LIST, userList);
     result.objectValue(next);
   } else {
     log(result.getReason().name());
     log(result.allMessages());
   }
   return result;
 }