Topic

Topic instances can be perceived as a street advertising columns. Components interested in some sort of messages will subscribe to appropriate Topic instance in MessageBus that controls message flow between message publishers and listeners.

For example, we might have some components interested in receiving beaver photo updates and components interested in receiving wombat photo updates. For this situation, we would create two Topics:

case object BeaverPhotosTopic extends Topic {
  val name = "beaver-photos"
}

case object WombatPhotosTopic extends Topic {
  val name = "wombat-photos"
}

All messages sent to BeaverPhotosTopic would be received only by components subscribed to BeaverPhotosTopic. All messages sent to WombatPhotosTopic would be received only by components subscribed to WombatPhotosTopic.