Message Relay Service (MRS.)
Message Relay Service for Swift/Obj-C. This is a messaging service that utilizes protocols to subscribe/publish through a dispatch and receiver. This can be useful in apps designed around plug-in pattern, and others.
How is this different than NotificationCenter?
Protocols ofcourse! Using a protocol adds a layer of decoupling (like we do for delegation), and ensures you aren't able to send a message the listener isn't expecting.
You'll create a Dispatcher and Receiver, initialed with a specified protocol. Listeners will add to the Dispatcher, which will compiler enforce they are of the protocol type on the addListener method. The Receiver object acts as a proxy for the protocol type, so that any method in protocol, is available to be called on the Receiver object. Calling a method on the Receiver, triggers that same method on all of the listeners!
How do I set this thing up?
- Create your protocol!
@objc protocol PlaybackProtocol {
func hasBecomeReady(duration: Double)
func timeUpdated(time: Double)
func playTriggered()
func pauseTriggered()
}
- setup your dispatcher! (and receiver)
# replace `PlaybackProtocol` here with whatever protocl you are using!
let playbackDisatch: MRSDispatcher<PlaybackProtocol> = MRSDispatcher()
let playbackReciever: PlaybackProtocol = playbackDisatch.targetReciever
- add a listener! (as many listeners as you want!)
// add protcol to class!
class TimeDisplayViewController: UIViewController, PlaybackProtocol {
// don't forget the method for protocol! (compiler won't let you forget, so don't worry bout it.)
func hasBecomeReady(duration: Double) { ... }
func timeUpdated(time: Double) { ... }
func playTriggered() { ... }
func pauseTriggered() { ... }
// listen to that dispatcher!!!
func viewDidLoad() {
super.viewDidLoad()
// Here we go!
RelayCenter.playbackDisatch.addListener(self)
....
}
...
- Fire the dispatcher, and the listener's methods get called!!!
func myTimeHasChanged(newTime: Double) {
RelayCenter.playbackReciever.timeUpdate(time:newTime)
}