MessageBus

MessageBus is a small and simple library written in swift for the simple use of broadcasting and receiving events.

Usage

Creation

A MessageBus can be created as an object. Other then NSNotificationCenter in OSX you can have as many instances as you want.

let messageBus : MessageBus = SimpleMessageBus()

Register events

MessageBus clients can register to observe events from the message bus.

Note that MessageBus infers the type of e from the observation class type Event.self.

messageBus.observe(Event.self) { (e) in
}

// e preserves the type of MyCustomEvent
messageBus.observe(MyCustomEvent.self) { (e) in

}

Post events

MessageBus is being intended to be used accross services in a broader application.

As any event pattern this services can send events such as the following sample.

let event = MyCustomEvent()
messageBus.post(event)

Subsequent events

MessageBus safely handles subsequentially posted events when it comes to order.

Note the following issue:

messageBus.observe(Purchase.self) { (purchaseEvent) in
  let trackEvent = TrackEvent(purchaseEvent)
  messageBus.post(trackEvent)
}

MessageBus defers the execution of the posting for the trackEvent right immediatly after the Purchase Event observation block has been exited its context, but still sustains the event order.