Using Swift Protocol Extensions for strongly typed coding

CodingKeyType.swift

protocol CodingKeyType {
    typealias CodingKey: RawRepresentable
}

extension CodingKeyType where Self: NSCoding, CodingKey.RawValue == String {
    static func decodeObject<T: AnyObject>(inout objv: T?, fromCoder aDecoder: NSCoder, forKey key: CodingKey) {
        guard let object = aDecoder.decodeObjectOfClass(T.self, forKey: key.rawValue) as? T? else {
            fatalError("Failed to decode a value of type \(T.self)")
        }
        
        objv = object
    }
    
    static func encodeObject<T: AnyObject>(objv: T?, toCoder aCoder: NSCoder, forKey key: CodingKey) {
        aCoder.encodeObject(objv, forKey: key.rawValue)
    }
}

Person.swift

class Person: NSObject, NSCoding, CodingKeyType {
    enum CodingKey: String {
        case Name = "name"
    }
    
    let name: String
    
    required init?(coder aDecoder: NSCoder) {
        var name: NSString?
        Person.decodeObject(&name, fromCoder: aDecoder, forKey: CodingKey.Name)
        self.name = name as! String
    }
    
    func encodeWithCoder(aCoder: NSCoder) {
        Person.encodeObject(name as NSString, toCoder: aCoder, forKey: CodingKey.Name)
    }
}