protocol extesion 이용한 Default

프로토콜에서 사용되는 함수나 프로퍼티의 디폴트값을 넣고싶은경우 extension 을 사용하면된다

protocol AppleDevice {
    func findMyDevice()
    func checkSerialNumber()
    var modelNumber:String {
        get set
    }
}
extension AppleDevice {
    func findMyDevice() {
        print("Find My AppleDevice...")
    }
    func checkSerialNumber() {
        print("You Can Check your SerialNumber Froe Box")
    }
    var modelNumber:String {
        get { return "Not Yet"}
        set { modelNumber = newValue}
    }
}

class iPhone: AppleDevice {
    var modelNumber: String {
        return "MNP-23"
    }
    
    var master:AppleCompany?
        init(master:AppleCompany) {
            master.delegate = self
        }
        var serialNumber: String {
            var SerialNumber = "iPhone"
            for _ in 0...15 {
                SerialNumber += String(Int.random(in: 0...9))
            }
            return SerialNumber
        }
        func findMyDevice() {
            print("Find My Iphone...")
        }
    func checkSerialNumber() {
        print(self.serialNumber)
    }

}

class Ipad: AppleDevice {
    var master:AppleCompany?
    var modelNumber: String {
        return "MAT-19"
    }
    
    init(master:AppleCompany) {
        master.delegate = self
    }
        var serialNumber: String {
            var SerialNumber = "iPad"
            for _ in 0...15 {
                SerialNumber += String(Int.random(in: 0...9))
            }
            return SerialNumber
        }
        func findMyDevice() {
            print("Find My Ipad...")
        }
    func checkSerialNumber() {
        print(self.serialNumber)
    }

}
class iMac: AppleDevice {
    var modelNumber: String {
        return "MO3-38"
    }
    var master:AppleCompany?
    var serialNumber: String {
        var SerialNumber = "iMac"
        for _ in 0...15 {
            SerialNumber += String(Int.random(in: 0...9))
        }
        return SerialNumber
    }
    
    init(master:AppleCompany) {
        master.delegate = self
    }
    
    func findMyDevice() {
        print("Find My iMac...")
    }

    func checkSerialNumber() {
        print(self.serialNumber)
    }
}

class AppleCompany {
    var delegate:AppleDevice?

    func RecallDevice() {
        print("Recall device")
    }
    func forcedFindMyDevice() {
        delegate?.findMyDevice()
    }
}

class newDevice:AppleDevice {
    
    var master:AppleCompany?
    var serialNumber: String {
        var SerialNumber = "new"
        for _ in 0...15 {
            SerialNumber += String(Int.random(in: 0...9))
        }
        return SerialNumber
    }
    
    init(master:AppleCompany) {
        master.delegate = self
    }
}
let steave = AppleCompany()

let iPhone13 = iPhone(master: steave)
print(iPhone13.modelNumber)
iPhone13.checkSerialNumber()
steave.forcedFindMyDevice()
let iPad3 = Ipad(master: steave)
print(iPad3.modelNumber)
iPad3.checkSerialNumber()
steave.forcedFindMyDevice()
let iMac3 = iMac(master:steave)
print(iMac3.modelNumber)
iMac3.checkSerialNumber()
steave.forcedFindMyDevice()
let newDevice3 = newDevice(master: steave)
newDevice3.findMyDevice()
newDevice3.checkSerialNumber()
print(newDevice3.modelNumber)

//출력값
MNP-23
iPhone2997174408378184
Find My Iphone...
MAT-19
iPad1105544854982974
Find My Ipad...
MO3-38
iMac2108360658256554
Find My iMac...
Find My AppleDevice...
You Can Check your SerialNumber Froe Box
Not Yet

newDevice class 안에는 따로 프로토콜 함수나 프로퍼티를 정의하지않아도 extension에서 정의한 값이 호출된다...