http://yuml.me/diagram/scruffy/class/draw

[INotificationSender|+send(message:string)]
[INotificationSender]^-.-[SmsNotificationSender]
[INotificationSender]^-.-[NotificationSenderMock]

[Service|start()]+[<<INotificationSender>>]
[Service]-[note:Send a notification when the service is started{bg:wheat}]