Refactoring to Design Patterns (phpDay 2009)

@ phpDay 2009

Transcript

1. Refactoring to Design Pa0erns Simone Carle5 phpDay 2009 – May 15‐16, 2009 – Verona, Italy h0p://grusp.it ‐ h0p://phpday.it ‐ h0p://joind.in/event/view/34
2. About Me •  Technical Manager in Altura Labs •  Addicted to Agile Development •  Fallen in love with Development Best Prac=ces •  Passionate about Object Oriented Programming phpDay 2009 – 15 e 16 Maggio Verona, Italy
3. Designing object oriented soKware is hard, and designing reusable object‐oriented soKware is even harder. Design Pa*erns (GoF) phpDay 2009 – 15 e 16 Maggio Verona, Italy
4. EvoluRon
5. Maintainability phpDay 2009 – 15 e 16 Maggio Verona, Italy
6. Maintainability Long project lifecycle phpDay 2009 – 15 e 16 Maggio Verona, Italy
7. Maintainability Long project lifecycle Scalability phpDay 2009 – 15 e 16 Maggio Verona, Italy
8. Maintainability Long project lifecycle Scalability Flexibility phpDay 2009 – 15 e 16 Maggio Verona, Italy
9. … and we need it for yesterday! phpDay 2009 – 15 e 16 Maggio Verona, Italy
10. Design for Changes The key to maximizing reuse lies in an=cipa=ng new requirements and changes to exis=ng requirements, and design your system so that they can evolve accordingly. Design Pa*erns (GoF) phpDay 2009 – 15 e 16 Maggio Verona, Italy
12. Bad Smell hVp://www.codinghorror.com/blog/ archives/000589.html
13. D.R.Y. Don’t repeat yourself
14. K.I.S.S. Keep it Simple, Stupid
15. Y.A.G.N.I. You Ain't Gonna Need It
16. Over‐Engineering phpDay 2009 – 15 e 16 Maggio Verona, Italy
17. Under‐Engineering phpDay 2009 – 15 e 16 Maggio Verona, Italy
18. Refactoring
19. phpDay 2009 – 15 e 16 Maggio Verona, Italy
20. What is Refactoring? Refactoring is a disciplined technique for restructuring an exis=ng body of code, altering its internal structure without changing its external behavior. Mar2n Fowler phpDay 2009 – 15 e 16 Maggio Verona, Italy
21. Why? •  Improve readability •  Improve maintainability •  Gain a beVer understanding of code phpDay 2009 – 15 e 16 Maggio Verona, Italy
22. How? •  Small steps •  Con=nuous •  Don’t add features •  … or bugs •  Have a good knowledge of the code phpDay 2009 – 15 e 16 Maggio Verona, Italy
23. Design Pa0erns
24. Design PaVerns describe simple and elegant solu=ons to specific problems in object oriented soKware design. phpDay 2009 – 15 e 16 Maggio Verona, Italy
25. phpDay 2009 – 15 e 16 Maggio Verona, Italy
26. Each paVerns describes a problem which occurs over and over again in our environment, and then describes the core of the solu=on to that problem, in such a way that you can use this solu=on a million =mes over. Christopher Alexander phpDay 2009 – 15 e 16 Maggio Verona, Italy
27. Context Problem Solu=on phpDay 2009 – 15 e 16 Maggio Verona, Italy
28. A word of warning Ideally when the appropriate problem comes along, you should trigger the design paVern and your problem is solved. Russ Olsen, Design Pa*erns in Ruby phpDay 2009 – 15 e 16 Maggio Verona, Italy
29. Design Pa0erns by Purpose •  Crea=onal PaVerns •  Structural PaVerns •  Behavioral PaVerns •  Concurrency PaVerns •  Architectural PaVerns phpDay 2009 – 15 e 16 Maggio Verona, Italy
30. There is a natural rela=on between paVerns and refactorings. PaVerns are where you want to be, refactorings are ways to get there from somewhere else. Mar2n Fowler phpDay 2009 – 15 e 16 Maggio Verona, Italy
31. TesRng
32. phpDay 2009 – 15 e 16 Maggio Verona, Italy
33. TesRng performance integra=on func=onal unit phpDay 2009 – 15 e 16 Maggio Verona, Italy
34. Test Driven Development phpDay 2009 – 15 e 16 Maggio Verona, Italy
35. Tes=ng Refactoring Design PaVerns phpDay 2009 – 15 e 16 Maggio Verona, Italy
36. Refactoring to Design Pa0erns
37. Observer
38. Observer The Observer paVern defines dependency between objects so that when one object change state, all its dependents are no=fied and updated automa=cally phpDay 2009 – 15 e 16 Maggio Verona, Italy
39. Observer Post CacheSweeper Logger EmailNo=fier phpDay 2009 – 15 e 16 Maggio Verona, Italy
40. Observer Post CacheSweeper Logger EmailNo=fier $post‐>=tle = “foo”; $post‐>save(); phpDay 2009 – 15 e 16 Maggio Verona, Italy
41. Observer Post CacheSweeper Logger EmailNo=fier $post‐>=tle = “foo”; $post‐>save(); phpDay 2009 – 15 e 16 Maggio Verona, Italy
42. Observer Post CacheSweeper Logger EmailNo=fier $post‐>=tle = “foo”; $post‐>save(); aKer_save() aKer_save() aKer_save() phpDay 2009 – 15 e 16 Maggio Verona, Italy
43. Observer Post CacheSweeper Logger EmailNo=fier $post‐>delete(); phpDay 2009 – 15 e 16 Maggio Verona, Italy
44. Observer Post CacheSweeper Logger EmailNo=fier $post‐>delete(); phpDay 2009 – 15 e 16 Maggio Verona, Italy
45. Observer Post CacheSweeper Logger EmailNo=fier aKer_delete() aKer_delete() $post‐>delete(); phpDay 2009 – 15 e 16 Maggio Verona, Italy
46. Code Time
47. Strategy
48. Strategy function doSomething($even, $odd) { if ($even == "secret") { if ($odd == "other secret") { return 1; } else if ("pizza" == "good") { return "Yes it is!"; } } else if ($odd != $even) { return "yeah, they are"; } else { return "I'm getting crazy"; } } phpDay 2009 – 15 e 16 Maggio Verona, Italy
49. Strategy method($params) { // complex logic // conditional strategy } phpDay 2009 – 15 e 16 Maggio Verona, Italy
50. Strategy Strategy 1 Strategy 2 Strategy 3 method($params) { $s = new Strategy(); $s->method($params); } $s = new Strategy() $s->method($params); phpDay 2009 – 15 e 16 Maggio Verona, Italy
51. Code Time
52. QuesRons? phpDay 2009 – 15 e 16 Maggio Verona, Italy
53. License This presenta=on is published under the AVribu=on‐Share Alike Unported Crea=ve Commons License. You are free: •  to Share — to copy, distribute and transmit the work •  to Remix — to adapt the work Under the following condi=ons: •  A0ribuRon — You must aVribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). •  Share Alike — If you alter, transform, or build upon this work, you may distribute the resul=ng work only under the same, similar or a compa=ble license. Visit hVp://crea=vecommons.org/licenses/by‐sa/3.0/ for more details. phpDay 2009 – 15 e 16 Maggio Verona, Italy
54. Thank you! Slides will be available at www.simonecarleq.com www.slideshare.net/weppos Rate this talk at hVp://joind.in/talk/view/417