A Signal equivalent for the EventMap

The robotlegs Mediator makes use of the EventMap to help with automatic clean-up when the mediator is removed.

Without clean up, memory leaks and duplication of listeners can occur as your views come and go from the stage and your mediators are created and destroyed.

The SignalMediator provides a SignalMap to handle this unmapping for you when the mediator is removed.

Usage

Where your mediator makes use of a Signal - whether injected or on the view - extend SignalMediator.

Instead of registering a listener with a signal directly, make use of the addToSignal and addOnceToSignal methods.

override public function onRegister():void
{
	// add normally
	addToSignal(someInjectedSignal, someHandler);       
	
	// add once
	addOnceToSignal(view.submit, submitHandler);
}   

The SignalMediator will then make use of the SignalMap to add the handlers to these signals, and when the mediator is destroyed the handlers will all be unmapped. (Via the preRemove() method which is called by the MediatorMap automatically when views leave the stage).

To manually unmap a signal-listener

The sugar methods addToSignal and addOnceToSignal are provided for convenience. You can also access the SignalMap property of the SignalMediator directly, and you should use this approach to manually remove a signal (for example in response to another signal or a normal event listener):

signalMap.removeFromSignal(someInjectedSignal, someHandler);

You can also use the SignalMap outside of SignalMediator

SignalMap itself has no dependencies and can be used within a complex view, a service or any other place it might be useful to you. Even a controller if you're into that kind of thing.

Compatibility

This should be compatible with any 1.x robotlegs release, and at least 0.7 and 0.8 releases of signals. The SignalMap makes use of the Vector class - available only in Flash Player 10+. It should be trivial to switch out the Vector for an array if you required FP 9 usage.