Swift3.0 - 类簇

class Drinking: NSObject{
    class func drink(name:String) -> Drinking?{
        var drink: Drinking?
        switch name {
        case "Coke" : drink = Coke(name: name)
        case "Beer" : drink = Beer(name: name)
        default :break;
        }
        return drink
    }
 }
class Coke:Drinking {
    var name:String
    init(name: String) {
        self.name = name
    }
}

class Beer:Drinking {
      var name:String
    init(name: String) {
        self.name = name
    }
}

let coke = Drinking.drink(name: "Coke") as! Coke
print(coke.name)