1.
#Swift3Arch
Dependence day:
Insurgence
Jorge D. Ortiz Fuentes
@jdortiz

2.
A Canonical
Examples
Production
#Swift3Arch

3.
#Swift3Arch
Agenda
The Problem
Solutions
Recommendations

4.
The Problem

5.
#Swift3Arch
Job Description
Understand the problem
Identify the right set of pieces
Put proper names
Make them run together properly

6.
#Swift3Arch
Social Network Option A
Social Network

7.
#Swift3Arch
Video
Text
Image
Social Network Option B
User PostGroup
Discussion
Promotion
DM

8.
#Swift3Arch
Single Responsibility
Principle
View
Controller
Presenter
View Model
Model
Presentation
logic
Business
Logic
Data
Source
Data
Source
Data
Source
Navigation

9.
The Jigsaw
Puzzle

10.
#Swift3Arch
Making it work
Objects require other objects to work ->
Dependencies
Each object creates its dependencies
Bad idea™
• Another responsibility
• What if we want to use it with different
sets of pieces?

11.
Instanciation
=
alien is born

12.
Test
environment

13.
#Swift3Arch
How to Provide
Dependencies
Initializer
Property
Method

14.
But Who?

15.
Frameworks to the
rescue

16.
#Swift3Arch
Inversion of Control
Hollywood Principle

17.
#Swift3Arch
Dependency Inversion
Containers
Dip
Swinject
Cleanse

18.
#Swift3Arch
Dip
Created by Olivier Halligon, maintained by Ilya
Puchka
Beautifully simple
Nice way to inject in Storyboards
Scopes, Named definitions, Runtime arguments,
Circular dependencies, Auto-wiring & Auto-injection,
Type forwarding, Storyboards integration, Weakly
typed components, Easy configuration, Thread
safety, Helpful error messages, and configuration
validation.

19.
#Swift3Arch
Dip
func configure(container: DependencyContainer) {
container.register(.unique) { InMemoryRepo() }
container.register(.unique) { try UseCaseFactory(entityGateway:
container.resolve() as InMemoryRepo) }
DependencyContainer.uiContainers = [showProgrammersListModule]
}
let showProgrammersListModule = DependencyContainer { container in
container.register() { try ProgrammersListPresenter(useCaseFactory:
container.resolve() as UseCaseFactory) }
container.register(tag: "ProgrammersTableVC")
{ ProgrammersTableViewController() }
.resolvingProperties { container, viewController in
viewController.presenter = try container.resolve() as
ProgrammersListPresenter
}
}
extension ProgrammersTableViewController: StoryboardInstantiatable {}

20.
#Swift3Arch
Swinject
Created by Jakub Vano, Wolfgang Lutz, Yoichi
Tagala
Pure Swift Type Support, Injection with
Arguments, Initializer/Property/Method
Injections, Initialization Callback, Circular
Dependencies, Object Scopes, Reference &
Value Types, Self-registration, Container
Hierarchy, Property Injection from Resource
files, Thread Safety, Modular Components,
Storyboard

21.
#Swift3Arch
Cleanse
Created by Square
Early version, but promising

22.
No Swift 3
Yet*!

23.
The World Outside

24.
#Swift3Arch
Java for Android
Standard annotations for DI (JSR330)
Introspection & Reflection
Many frameworks available
Some owned by Google (Guice & Dagger
2)

25.
Maturity

26.
What then?

27.
Traditional
methods

28.
#Swift3Arch
Assemble the Pieces
class ProgrammersListConnector {
// MARK: - Constants
let entityGateway: EntityGatewayProtocol
weak var presenter: ProgrammersListPresenter!
func assembleModule(view: ProgrammersTableViewController) {
let useCaseFactory = UseCaseFactory(entityGateway:
entityGateway)
let presenter = ProgrammersListPresenter(useCaseFactory:
useCaseFactory)
view.presenter = presenter
view.connector = self
presenter.view = view
self.presenter = presenter
}
}

29.
#Swift3Arch
Factories are your friend
protocol UseCase { func execute() }
class UseCaseFactory {
enum Use {
case showProgrammersList(completion:
ShowProgrammersListCompletion)
// …
}
func create(useCase whichUseCase: Use) -> UseCase {
switch whichUseCase {
case let .showProgrammersList(completion: completion):
return ShowProgrammersListUseCase(entityGateway:
entityGateway, completionHandler: completion)
// …
}
}

30.
Recap

31.
#Swift3Arch
Take aways
Make your dependencies explicit
Use factories
Understand how it a container works
Use DI frameworks with caution

32.
Thank
You!

33.
@jdortiz
#Swift3Arch