Swinject Example (Demo at iOSCon 2017 in London)

SwinjectExample.swift

// Demo at iOSCon 2017 in London
// https://speakerdeck.com/yoichitgy/dependency-injection-in-practice-ioscon
//
// Tested with: Xcode 8.2.1
//
// How to Use: 
// 1. Clone Swinject: git clone --recursive git@github.com:Swinject/Swinject.git
// 2. Checkout 2.0.0 branch: cd Swinject; git checkout 2.0.0
// 3. Build the Swinject project for a simulator target
// 4. Open the playground in the project
// 5. Replace the code of the playground with the following code
// 6. Run the playground

import Swinject // https://github.com/Swinject/Swinject

protocol Animal: class { }
class Cat: Animal { }

class PetOwner {
    let pet: Animal
    init(pet: Animal) {
        self.pet = pet
    }
}

// At program entry point
let container = Container()
container.register(PetOwner.self) { (resolver) in
    PetOwner(pet: resolver.resolve(Animal.self)!)
}
container.register(Animal.self) { _ in
    Cat()
}.inObjectScope(.container)


// Anywhere later
let anya = container.resolve(PetOwner.self)!
let yoichi = container.resolve(PetOwner.self)!

anya !== yoichi
anya.pet === yoichi.pet