GoF Design Patterns, a brief introduction about Creational patterns, Simple Factory and Factory Method

1. Design Patterns
in Swift
Ch 1
Creational Patterns
Simple Factory
Factory Method
Sai Li @ Yowoo Tech.
taipingeric@gmail.com
2017/4/25

2. Agenda
• Creational Patterns
• Simple Factory
• Factory Method
2

3. References
搞笑談軟⼯工
by Teddy Chen
3
⼀一本聖經，各⾃自表述

4. 1. Factory Method
2. Strategy
3. Decorator
4. Composite
5. Iterator
6. Template Method
7. Abstract Factory
8. Builder
9. Singleton
10. Proxy
11. Adaptor
Kerievsky Joshua: A Learning Guide To Design Patterns
12. Bridge
13. Mediator
14. Observer
15. Chain of Responsibility
16. Memento
17. Command
18. Prototype
19. State
20. Visitor
21. Flyweight
22. Interpreter
23. Facade
Kerievsky Joshua: A Learning Guide To Design Patterns

5. purpose
creational structural behavioral
scope
class Factory Method Adaptor
Interpreter
Template Method
object
Abstract Factory
Builder
Prototype
Singleton
Adapter
Bridge
Composite
Decorator
Facade
Flyweight
Proxy
Chain of Responsibility
Command
Iterator
Mediator
Memento
Observer
State
Strategy
Visitor

6. OOP
• DIP: depends on interface
6

7. • Swift
‣ let myPhone = Phone()
• Java
‣ Phone myPhone = new Phone()
• Javascript
‣ var myPhone = new Phone()
init()

8. Creational Patterns
• Abstracting initialization process
• Theme
1. Encapsulate concrete class knowledge
2. Hiding instance creation and composition by
knowing interface only
3. Flexibility: What, Who, How, When
4. static -> compiling time, dynamic -> runtime
8

9. Simple Factory

15. Factory Method

16. Factory Method
Define an interface for creating an object, but let
subclasses decide which class to instantiate.
Factory Method lets a class defer instantiation to
subclasses.
16
定義⽣生成物件的介⾯面，但讓⼦子類別決定該實體化哪
⼀一種物件。
Factory Method使類別實體化交付於(延遲⾄至)⼦子類別
處理理

17. Product Creator

18. created object’s interface
concrete implementation
1.define Factory Method Interface
(2. default implementation)
override Factory Method
to return ConcreteProduct
…
let product = FactoryMethod()
…
return ConcreteProduct()

19. << create >>

21. factory method

23. extension

24. Simple Factory
vs.
Factory Method

25. w/o default implementation

26. References
• 搞笑談軟⼯工
• Kerievsky Joshua: A Learning Guide To Design Patterns
26
Q & A