1. Introduction to Yan Cui Aspect Oriented Programming by theburningmonk.com @theburningmonk

2. Server-side Developer @

4. Overview  Cross-Cutting Concerns  AOP  What’s in it for you AOP  Terminologies  AOP and OOP  Solutions Q&A

5. C ROSS -C UTTING C ONCERNS the PROBLEM...

6. Image by Mike Rohde Cross-Cutting Concerns

7. Cuts across multiple abstractions Difficult to decompose High-coupling Boilerplate code

8. Code tangling and scattering  Poor traceability  Lower productivity  Less code reuse  Harder refactoring

9. A SPECT -O RIENTED P ROGRAMMING the SOLUTION...

10. “AOP is a programming paradigm which aims to increase modularity by allowing the separation of cross-cutting concerns” - wikipedia

11. AOP

12. Image by Mike Rohde AOP

14. Centralize concerns implementation Intercept method calls Inject new behaviour More reusable code Cleaner code

15. What’s in it for YOU ?

16. Write less code Read less code More concise and easy to understand More maintainable

17. Fewer code = Less boilerplate code More interesting work Increased attention More PRODUCTIVITY! FEWER DEFECTS!

18. AOP dive a little deeper into...

19. Join Point  Place where behaviour can be added  start/end of method  property getter/setter ...

20. Advice  Code that’s injected at join points  Logging  Validation ...

21. Point cut  Join points where advice should be applied

22. Aspect  Container holding point cuts and advice  Aspect is to AOP what class is to OOP

23. Weaving  Combines advices with point cuts

24. AOP is complementary to OOP AOP targets a specific problem Code modularization  OOP – Real world objects  AOP – Functionalities

25. Help you S.O.L.I.Dify your code  Single responsibility  Open/close

26. You can do AOP via:  Dynamic Proxies  Functional Programming  Code Generation  Dynamic Languages  Static Weaving

27. D YNAMIC P ROXIES AOP via...

28. IoC framesworks  Castle  Spring.Net Dynamic interceptors

29. Image by Mike Rohde Dynamic Proxies

31. Advantages  Can use existing DI framework  Built-in aspects (logging, etc.)  Aspects can be configured after build

32. Disadvantages  Significant change to base code required to adapt  Limited AOP features  Do not work on static, non-public methods  Do not work on fields, properties, or events  Higher run-time overhead  No build-time verification  Objects must be instantiated using the container

33. Class, is AOP the same as Dependency Injection? NOOOO Sir!!

34. F UNCTIONAL P ROGRAMMING AOP via...

35. Image by Mike Rohde Functional Programming

37. Advantages  No external dependencies

38. Disadvantages  Requires modification to every function  No support for matching rules  Manual aspect composition

39. C ODE G ENERATION AOP via...

40. T4, CodeSmith tools

41. Advantages  Easy to generate complex source code

42. Disadvantages  Input is usually XML  Cannot inject new behaviour to existing code

43. D YNAMIC L ANGUAGES AOP via...

44. Image by Mike Rohde Dynamic Languages

45. Advantages  Meta-programming is easy

46. Disadvantages  Switch to a dynamic language can be hard  No (limited) Visual Studio tooling

47. S TATIC W EAVING AOP via...

48. PostSharp, AspectJ Uses low-level MSIL transformation Compile time

49. Aspect Decomposition Aspects Core program Aspect Recomposition Requirements Final System

50. Image by Mike Rohde PostSharp

51. Advantages  Most complete support of AOP features  Aspect usage is verified at build time  Better runtime performance

52. Disadvantages  Increased build time  New to many developers

53. PostSharp Examples Auto-implement INotifyPropertyChanged Undo/Redo Thread dispatching Transaction handling Performance Monitoring

54.  Method execution time  Method execution count  Error count

55. Record exec time Publish to Amazon CloudWatch

57. Amazon CloudWatch  Cheap to run  Supports alarms and notifications  Visualization tool

58. http://bit.ly/KRDdgr

59. Thank You! @theburningmonk theburningmonk.com @theburningmonk theburningmonk.com