I'm implementing a Model View Control program.
I have a class User that has a list of photo albums, so I have a method addAlbum(String name).
My question is, since the controller is supposed to verify that all data is valid, should the controller verify that user doesn't have an album with that name. in other word, should the precondition of addAlbum be that the album doesn't exist, or is it OK to traverse the list of albums (inside class user), verifying that album doesn't exist?