delegation pattern 응용

생각보다 delegation pattern(d.p) 중요한 디자인패턴같다
우선 좋은 유튜브영상을 공유합니다
https://www.youtube.com/watch?v=JV1BKdz9hUA

d.p를 사용하면 특정 struct Data Fetch 하는개념을 Service라는 다른 클래스의 객체를 생성해서 진행할수있고 썸네일에 나와있는것처럼 4가지 편리함이 있다

struct ReservationPeople {
    let count:Int
    let name:String
    
}

protocol AppleStore {
    func didFetchReservation(_ reservationPeople:ReservationPeople)
}

protocol GeniusBar {
    var reservationPeople:ReservationPeople? {
        get
    }
}

class ReservationService {
    
    var delegate: AppleStore?
    var dataSource: GeniusBar?
    
    func fetchReservation() {
        guard let dataSource = dataSource else {
            return
        }
        let reservationName = dataSource.reservationPeople?.name
        let reservationCount = dataSource.reservationPeople?.count
        let reservationPeople = ReservationPeople(count:reservationCount ?? 0, name:reservationName ?? "")
        delegate?.didFetchReservation(reservationPeople)
    }
}

struct KoreanAppleStore: AppleStore, GeniusBar {
    let reservationService = ReservationService()
    
    init() {
        reservationService.delegate = self
        reservationService.dataSource = self
        
    }
    func makeReservation() {
        reservationService.fetchReservation()
    }
    
    func didFetchReservation(_ reservationPeople: ReservationPeople) {
        print(reservationPeople.name)
        print(reservationPeople.count)
    }
    
    var reservationPeople: ReservationPeople? {
        let _name: String? = reservationPeople?.name
        let _count:Int? = reservationPeople?.count
        let _value = ReservationPeople(count: _count ?? 0, name: _name ?? "")
        return _value
    }
}

let reservationFirst = ReservationPeople(count: 3, name: "David")

let Garosulgill = KoreanAppleStore()

let reservationService = ReservationService()

Garosulgill.didFetchReservation(reservationFirst)

reservationService.fetchReservation()

let reservationSecond = ReservationPeople(count:5, name: "D-Park")

Garosulgill.didFetchReservation(reservationSecond)

reservationService.fetchReservation()

//출력값
David
3
D-Park
5