Design patterns and MV
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This document discusses design patterns and the model-view-controller (MVC) framework. It introduces common design patterns like singleton, strategy, and observer. It then explains the history and components of MVC, including how the view displays information to the user, the controller handles user input, and the model manages application data. The document emphasizes that design patterns and MVC help create extensible and maintainable code.
![Is Your Singleton Broken?
• The singleton pattern must be carefully
constructed in multi-threaded applications
• [OSDC 2014] fr3@K - Is Your Singleton
Broken? - YouTube](https://image.slidesharecdn.com/designpatteernsandmvc-150702154515-lva1-app6891/85/Design-patterns-and-MV-10-320.jpg)
![Is Your Singleton Broken?
• The singleton pattern must be carefully
constructed in multi-threaded applications
• [OSDC 2014] fr3@K - Is Your Singleton
Broken? – YouTube
• Global variable issue](https://image.slidesharecdn.com/designpatteernsandmvc-150702154515-lva1-app6891/85/Design-patterns-and-MV-11-320.jpg)
Design patterns and MV
- 1. Design Patterns and MVC Sway Wang 2014.12.25
- 2. Outline • What is Design Pattern? – Singleton pattern – Strategy pattern – Observer pattern • What is MVC? – C# example – Ruby on Rails • Conclusion
- 3. What is Design Pattern? • Patterns are formalized best practices that the programmer can use to solve common problems when designing an application or system
- 4. The History of Design Pattern • Christopher Alexander (1977) • Kent Beck and Ward Cunningham (1987) • Gamma, Erich; Richard Helm, Ralph Johnson, and John Vlissides – Design Patterns: Elements of Reusable Object- Oriented Software (1995)
- 5. History
- 6. Gang of Four (GoF) Patterns • Creational Patterns (abstracting the object-instantiation process) – Factory Method Abstract Factory – Singleton Builder – Prototype • Structural Patterns (how objects/classes can be combined to form larger structures) – Adapter Bridge – Composite Decorator – Facade Flyweight – Proxy
- 7. Gang of Four (GoF) patterns • Behavioral Patterns (communication between objects) – Command Interpreter Iterator – Mediator Observer State – Strategy Chain of Responsibility Visitor – Template Method
- 8. Singleton Pattern • It restricts the instantiation of a class to one object
- 10. Is Your Singleton Broken? • The singleton pattern must be carefully constructed in multi-threaded applications • [OSDC 2014] fr3@K - Is Your Singleton Broken? - YouTube
- 11. Is Your Singleton Broken? • The singleton pattern must be carefully constructed in multi-threaded applications • [OSDC 2014] fr3@K - Is Your Singleton Broken? – YouTube • Global variable issue
- 12. Strategy Pattern • It enables an algorithm's behavior to be selected at runtime
- 13. Strategy Pattern: Duck Example
- 14. Now We Need the Ducks to Fly
- 15. Now We Need the Ducks to Fly
- 16. Decoy Duck
- 17. How About a Interface? Duplicate code
- 18. Strategy Pattern: Duck Example
- 19. Strategy Pattern: Duck Example
- 20. Strategy Pattern: Duck Example
- 21. Strategy Pattern: Duck Example
- 22. Strategy Pattern: Duck Example
- 24. Strategy Pattern: Duck Example
- 26. Open-Closed Principle(OCP) Software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification 一個軟體應該要夠開放使得它可以被擴充， 但是也要夠封閉以避免不必要的修改
- 27. Strategy Pattern • It enables an algorithm's behavior to be selected at runtime
- 28. Observer Pattern • Newspaper subscription • Publishers + Subscribers = Observer Pattern
- 29. Observer Pattern • Newspaper subscription • Publishers + Subscribers = Observer Pattern
- 30. Observer Pattern
- 31. Observer Pattern
- 35. The History of MVC • MVC is really old and was first described in 1979 by Trygve Reenskaug • Smalltalk at Xerox PARC. • Today MVC is used in most modern web and GUI frameworks
- 36. The History of MVC • Ruby On Rails: A popular Ruby web- framework • Apple Cocoa: Apple's framework for developing Mac OS and iOS applications • ASP.Net Framework: Microsoft's web- framework for implementing web applications • ... And many many more languages and frameworks
- 37. MVC
- 38. View
- 39. Controller
- 40. Model
- 41. Perl CGI – 計數器
- 42. PHP計數器
- 43. Ruby on Rails
- 44. 缺點 • HTML和邏輯綁在一起 • 網站規模變大後不易修改 • 難以分工 • Web Framework – 導入OO概念 – 制定好了一套規範和慣例，讓開發者在該架構下來進行 開發
- 45. Web Framework • 導入OO概念 • 制定好了一套規範和慣例，讓開發者在該架 構下來進行開發
- 46. Conclusion • 要精通OOP一定要會Design Pattern • Design Pattern三種境界 – 什麼東西都套pattern – 知道什麼時候該用pattern – KISS principle • MVC架構的AP後續維護較容易 • 設計良好的程式碼當未來需求變更時，較容易改 變