I am developing a Game Project and wish to use the Object Composition pattern to give me a great deal of flexibility. I currently override message forwarding methods in order that the Composite can invoke the methods of its Components.
The only downside to this is that -forwardingTargetForSelector: only works when there is to be only one target. If I have a Composite with two Components that have the same selector, then I will have to resort to using the (much slower) -forwardInvocation method and perform the NSInvocation on both the targets.
From reading a few books on advanced Objective-C and Runtime reference, it seems that I may be able to forward messages by dynamically creating an implementation that will invoke the IMP in the child Component Classes. I would use the Runtime method class_addmethod to do this.
My question is, does anyone know if Apple considers this to be private API and thus against App Store Rules? Has anyone used class_addmethod in Apps that have passed review?
It is common knowledge that method swizzling is not allowed in the store, but this is not exactly the same thing. One typical example was swizzling the -drawRect: on UINavigationBar, before the Appearance API was available. This would be adding methods to my own object rather than messing with Apple’s own API.
Thanks for Reading!
Lawrence
From what I’ve read as long as you’re not swizzling Apple provided classes to alter functionality, you should be fine. The Objective-C runtime isn’t a private API, so if this is all happening on your own code then you should be fine to do this.