## 25.6.2 CRC Cards for the Voice Mail System (cont.)

### Leave a Msg use case - simple scenario walkthrough

1. User types an extension:
   - `Telephone` sends number to `Connection`
   - `Connection` collaborator of `Telephone`
   - Place the 2 cards adjacent)
2. `Connection` asks `MailSystem` to find appropriate `MailBox` object
   - Vaguely included in the "manage mailboxes" responsibility
   - Keep `MailSystem` and `Mailbox` cards close to `Connection` card
3. `Connection` asks `Mailbox` for its greeting
   - Add "manage greeting" to `Mailbox` responsibilities
   - add `Mailbox` as a collaborator of `Connection`

(cont.)

prev |top |next