Tell, Don't Ask Principle and Password Expiration

Question

Trying to keep with pragmatic programming principles, I'm trying to decide on how to handle user password changes based on the "Tell, Don't Ask" principle.

I have a user object whose password expires every 30 days. I need to be able to show a password expired/change password view if the password is expired. Asking the object if the password is expired (it's state) and then choosing which view to show seems like a violation of the principle.

What is the best way to handle this situation?

Answer 1

login
   model.validate();
   return model.show(self);

passwordExpired()
  return View("ChangePassword")

loginSuccess()
  return View("default")

class User
  show(aController)
      if passwordExpired
          return aContoller.passwordExpired()
     else return aContoller.loginSuccess()

Tell, Don't Ask, no exceptions, and it obeys the law of Demeter