1. Isn’t this a design
sofftek developer
Skill traciende lenguajes
Las bases que TODOS debemos
patterns talk?
tener.
Friday, October 14, 2011

2. aqui me pararia y me
largaba
Object Oriented
Design - Basics
Friday, October 14, 2011

3. ME
Como me siento?
Con quienes he
colaborado?
En que cosas te
apasionas?
• Emmanuel Delgado
• Ingeniero de Software para Crowd
Interactive
• UAA, INEGI, Softtek
• PHP, Perl, Javascript, Java, Ruby
• Apasionadazo
• @chischaschos
Friday, October 14, 2011

4. What makes a system
complicated?
code smell, you feel it
mario c nice code, shit happens eveywhere
same old problems
Friday, October 14, 2011

5. un cambio implica tocar
muchos lugares
Rigidity
Friday, October 14, 2011

6. cambio rompe lugares
inesperados
Fragility
Friday, October 14, 2011

7. dificil hacer la cosa
correcta
de diseño
de ambiente
Viscosity
Friday, October 14, 2011

8. duplicidad
no puedes reutilizar
componentes
componentes utiles, pero
separar es muy complicado
Immobility
Friday, October 14, 2011

9. mas de lo que ocupas
anticipas a
requerimientos
hard to understand
Unnecessary complexity
Friday, October 14, 2011

10. resultado de reutilizar
codigo copy paste
Unnecessary duplicity
Friday, October 14, 2011

11. la imagen es la misma
tendencia dificil de entender
codigo puede ser claro y legible
requieres esfuerzo constante
para seguir siendo leguible
Opacity
Friday, October 14, 2011

12. Rotten system usual smells
• Rigidity
• Fragility
ocurren poco a poco un
commit a la vez
• Viscosity
• Immobility
• Unnecessary duplicity and complexity
• Opacity
Friday, October 14, 2011

13. small building blocks
small shapes
Pequeñas formas ->
grandes diseños
Bellos?
Small components design
principles
Friday, October 14, 2011

14. Single Responsibility (SR)
Friday, October 14, 2011

15. SR- How do I achieve
it?
Friday, October 14, 2011

16. SR - Analyze your object
• Delegate
• Encapsulate what changes
Friday, October 14, 2011

17. SR - Delegate?
Friday, October 14, 2011

18. SR - Delegate! in ruby
Friday, October 14, 2011

19. SR - Delegate! in ruby
Friday, October 14, 2011

20. SR - Delegate! with rails
Friday, October 14, 2011

21. SR - Delegate! with rails
Friday, October 14, 2011

22. SR - Encapsulate what changes
interview question
Que es encapsular,
ejemplo ftp uploader
como ayuda churn,
idealmente los No picos
+------------------------------------+---------------+
| file_path | times_changed |
+------------------------------------+---------------+
| lib/churn/churn_calculator.rb | 14 |
| README.rdoc | 7 |
| lib/tasks/churn_tasks.rb | 6 |
| Rakefile | 6 |
| lib/churn/git_analyzer.rb | 4 |
| VERSION | 4 |
| test/test_helper.rb | 4 |
| test/unit/churn_calculator_test.rb | 3 |
| test/churn_test.rb | 3 |
+------------------------------------+---------------+
Friday, October 14, 2011

23. OC - Open for extension
closed for modification
Friday, October 14, 2011

24. OC - Don not reopen an
object
Friday, October 14, 2011

25. OP - Encapsulate and extend it
Friday, October 14, 2011

26. OC - Composition over
inheritance
Friday, October 14, 2011

27. OC - Composition
implemented
Friday, October 14, 2011

28. Dependency Inversion (DI)
Friday, October 14, 2011

29. DI - What is a dependency?
dependencia agrega
responsabilidades
responsabilidad da
razones para cambiar
vas a tener que hacer
cambios
entre menos mejor, asi
gastas mas tiempo
creando codigo obra d arte
Friday, October 14, 2011

30. DI - Depend upon abstractions
Si tu clase emplea servicios externos, o tiene
muchas librerias requeridas,
o ves demasiadas constantes, utilizalas tan tarde
como puedas.
Friday, October 14, 2011

31. Basic suggestions
• Only one responsibility per object
• Encapsulate what changes
• Depend upon abstractions
• Delegate responsibilities
• Composition over inheritance
• Extend components, do not reopen them
Friday, October 14, 2011

32. patrones de diseño
alguien identifico
problemas comunes
formas se repiten
evita crear patrones
hasta el ultimo momento
Afterwards common
shapes will arise
Friday, October 14, 2011

33. Observer
• THINK: monitoring
behavior
Friday, October 14, 2011

34. Observer - An observer
Friday, October 14, 2011

35. Observer - The observed
Friday, October 14, 2011

36. Strategy
• THINK: Interchangeable
algorithms
Friday, October 14, 2011

37. Strategy
como llegas aqui? cuando
un metodo ya tiene
varios branchings
Friday, October 14, 2011

38. gy - Interchangeable algorithms
como llegas aqui? cuando
un metodo ya tiene
varios branchings
Friday, October 14, 2011

39. Proxy
• THINK: Wrapping object
behavior, forward calls
Friday, October 14, 2011

40. Proxy
Friday, October 14, 2011

41. Template
• THINK: Predefined steps
Friday, October 14, 2011

42. Template- Required?
Friday, October 14, 2011

43. Template- Implemented
Friday, October 14, 2011

44. Decorator
• THINK: Present new
content based on
original content
Friday, October 14, 2011

45. Decorator - required?
Friday, October 14, 2011

46. Decorator - implemented
Friday, October 14, 2011

47. THE END
Friday, October 14, 2011

48. Conclusion
• Follow damn simple principles
• Do not program upon design patterns, let
them arise by themselves
• Refactor to design patterns
Friday, October 14, 2011

49. References - 1
Friday, October 14, 2011

50. References - 2
• CHURN: https://github.com/danmayer/churn
• http://vimeo.com/12350535
• http://vimeo.com/26330100
• http://confreaks.net/videos/257-larubyconf2009-the-building-
blocks-of-modularity
• https://www.destroyallsoftware.com/screencasts
Friday, October 14, 2011

51. References - 3
Friday, October 14, 2011

52. References - 4
pregunta para ustedes como mantienes el diseño
dia tras dia?
boy scout rule
tdd
refactor all the fucking time
Friday, October 14, 2011