Applying Protocol-Oriented Programming in Development
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Demo
Head back to Xcode to see how this works. First, create an extension on MediaCollection:
extension MediaCollection {
}
mutating func add(_ item: Item) {
self.items.append(item)
}
movieCollection.add(bourneIdentity)
movieCollection.add(oppenheimer)
func getDescription() -> String {
"Collection contains \(items.count) items"
}
struct MediaShelf: MediaCollection {
}
var items: [T] = []
struct MediaShelf<T: MediaItem>: MediaCollection
let catan = BoardGame(title: "Catan", price: 40)
let arkhamKnight = VideoGame(title: "Batman: Arkham Knight", price: 49.99, console: .xbox)
let tearsOfTheKingdom = VideoGame(title: "The Legend of Zelda: Tears of the Kingdom", price: 59.99, console: .switch)
let noTimeToDie = Movie(title: "No Time To Die", price: 19.99, duration: 163)
var boardGameShelf = MediaShelf<BoardGame>()
var movieShelf = MediaShelf<Movie>()
var videoGameShelf = MediaShelf<VideoGame>()
boardGameShelf.add(catan)
movieShelf.add(noTimeToDie)
videoGameShelf.add(arkhamKnight)
videoGameShelf.add(tearsOfTheKingdom)
print(boardGameShelf.getDescription())
print(movieShelf.getDescription())
print(videoGameShelf.getDescription())
extension MediaShelf where T == VideoGame {
func getDescription() -> String {
let xboxCount = items.filter({ $0.console == .xbox }).count
let playstationCount = items.filter({ $0.console == .playstation }).count
let switchCount = items.filter({ $0.console == .switch }).count
return "This collection contains \(xboxCount) Xbox games, \(playstationCount) Playstation games and \(switchCount) Switch games"
}
}
extension MediaShelf where T: Codable {
func printItems() throws {
let jsonEncoder = JSONEncoder()
let data = try jsonEncoder.encode(items)
if let string = String(data: data, encoding: .utf8) {
print(string)
}
}
}
struct BoardGame: MediaItem, Codable
try boardGameShelf.printItems()