Slides from presentation at agiledays09.

1. Agile Object Oriented Design SOLID principles [email_address]

2. Why it is Agile?

6. ?

8. principles != rules

9. Single Responsibility Principle

10. Problem domain Conceptual model Implementation

11. Problem domain Conceptual model Implementation ? ?

13. NOooo!!

14. Book Instrument 1 * 1 1 Position value: double

15. Book Position Listener 1 BookPosNode Book Position Listener 2 Network Application position position position

16. BookPosNode AbstractBookPosNode Subscriber SnapshotProvider HeartbeatMonitor StateMachine

17. 1

18. 2

19. 3

20. 4 the rest of the class is collapsed

21. 5 the rest of the class is collapsed

22. Open/Closed Principle

23. AbstractPositionNode BookPosNode Client

24. AbstractPositionNode BookPosNode JMSNode Client PositionWatcher Add Change

25. AbstractPositionNode BookPosNode JMSNode Client PositionWatcher Add NodeV2

26. Front-end Back-end Database Change

27. Liskov Substitution Principle

31. Ellipse-circle problem rectangle-square

32. Point x, y : int #equals() #hashCode()

33. Point x, y : int #equals() #hashCode() ColorPoint color : Color #equals() #hashCode()

34. Point x, y : int #equals() #hashCode() ColorPoint color : Color #equals() #hashCode() Can't extend like this preserving equals contract (Effective Java, Item 8)

35. @IViolateLSP

36. class Dog implements ICanBark … class Button implements IClickable …

37. Interface Segregation Principle

38. <<interface>> BigService Client1 Client2 Client3

39. <<interface>> BigService <<interface>> Service1 <<interface>> Service2 <<interface>> Service3 Client1 Client2 Client3

41. BookPositionNode <<interface>> ResubscribingNode AbsPosNode StateMachine Client uses uses

42. Dependency Inversion Principle

43. Client Service client service

44. Client <<interface>> Service ServiceImpl client service

45. client service

46. Client <<interface>> Service ServiceImpl client service

47. Client <<interface>> Service ServiceImpl client service

48. client service

49. Client <<interface>> Service ServiceImpl client service api

51. S RP O CP L SP I SP D IP

52. Single Responsibility Principle

53. Open/Closed Principle

54. Liskov Substitution Principle

55. Interface Segregation Principle

56. Dependency Inversion Principle

57. What else?

58. Problem domain Conceptual model Implementation

59. F**k Design

60. Zen Coding

62. and only then for computers Code is written for people

63. REP CRP CCP ADP SDP SAP

64. UML, patterns, and more...

66. Thanks!

67. S RP O CP L SP I SP D IP

68. http://weblogs.java.net/blog/82/2003/09/02/aristotles-error-or-agile-smagile http://blog.objectmentor.com/articles/2009/01/31/quality-doesnt-matter-that-much-jeff-and-joel http://www.codinghorror.com/blog/archives/000805.html http://www.youtube.com/watch?v=2k1uOqRb0HU http://blogs.msdn.com/brada/archive/2003/10/02/50420.aspx http://www.joelonsoftware.com/articles/LeakyAbstractions.html http://www.joelonsoftware.com/items/2009/09/23.html