Protocol.swift

protocol DataModel {
}

protocol DataModelRelationships {
    var relationships : [String: Array<DataModel>] { get }
}

protocol DataStore {
    func add<T : DataModel>(element: T)
}

class ActualDataStore : DataStore {


    func add<T : DataModel>(element: T) {

    }
    
    func add<U : protocol<DataModel,DataModelRelationships>>(element: U) {
        updateRelationships(element)
    }
    
    func updateRelationships<U: protocol<DataModel,DataModelRelationships> >(element: U) {
        println("this ran")
    }
    
}

class AcutalObject : DataModel, DataModelRelationships {
    
    var relationships : [String: Array<DataModel>] {
        return ["something": []]
    }
}

let object = AcutalObject()

let store = ActualDataStore()
store.add(object)