The model from the subscriber and publisher perspective is still the same. This means that chaining can be done at application deployment time, without impact on application code. Depending on event traffic expected, a suitable topology can be constructed. All this functionality is available via a simple API, which makes this especially attractive. The run-time behavior is as shown below.
Subscribers register for certain types of events.
They also provide a filter which allows the event broker to filter events before dispatch. This prevents any extraneous network traffic and is efficient. The event broker keeps track of all subscriptions for a given event type. When a publisher publishes an event, the event broker consults all subscriptions to determine subscribers who are registered for that event. A subscriber can be anchored or unanchored.