Objective-C. Should I sub-class or should I use a protocol?

Question

I have an example where a protocol would be ideal except for the fact that there is a subset of common state and a few methods that I want to share amongst all implementers of the protocol. This would suggest class sub-classing rather then protocol-ing. I am leary of using sub-classing do primarily to its inflexibility and general loose coupling.

Can someone suggest an clean solution to this example?

Thanks in advance.

-Doug

Answer 1

Perhaps a combination of protocol and composition would be cleaner. Where the protocol defines the common functionality, but reference a common data object that maintains the shared state.

This solution has worked well for me in some specific cases, hard to tell if this would accomplish what you want.