Writing high quality code for agile2012
- 1. 7/17/2012 Writing High Quality Code Agile 2012 www.ToBeAgile.com © Copyright 2009-2012 To Be Agile DB20120717 info@ToBeAgile.com www.techniquesofdesign.com info@techniquesofdesign.com COPYRIGHT © TECHNIQUES OF DESIGN DB20111207 Thank you for being here 2 http://ToBeAgile.com 1
- 2. 7/17/2012 I am David Bernstein 3 Standing on the shoulders of giants 4 http://ToBeAgile.com 2
- 3. 7/17/2012 What is quality? Service Products ? Software 5 What makes software good? 6 http://ToBeAgile.com 3
- 4. 7/17/2012 Correctness is not enough 7 Remember when? 8 http://ToBeAgile.com 4
- 5. 7/17/2012 Things change 9 Dealing with change 10 http://ToBeAgile.com 5
- 6. 7/17/2012 What makes code easy to change? 11 What makes code difficult to change? 12 http://ToBeAgile.com 6
- 7. 7/17/2012 Code pathologies 13 Rigidity – hard to repurpose 14 http://ToBeAgile.com 7
- 8. 7/17/2012 Viscosity – difficult to change 15 Complexity – unsure how to change 16 http://ToBeAgile.com 8
- 9. 7/17/2012 Opaque – difficult to understand 17 Brittleness – expensive to change 18 http://ToBeAgile.com 9
- 10. 7/17/2012 Pathologies scare us 19 It’s harder on larger projects 20 http://ToBeAgile.com 10
- 11. 7/17/2012 Quality in software 21 6 software qualities 22 http://ToBeAgile.com 11
- 12. 7/17/2012 Cohesive 1 23 Language and software 24 http://ToBeAgile.com 12
- 13. 7/17/2012 Class cohesion 25 Method cohesion 26 http://ToBeAgile.com 13
- 14. 7/17/2012 Pathologies of poor cohesion 27 Non-redundant 2 28 http://ToBeAgile.com 14
- 15. 7/17/2012 Finding redundancy 29 Types of redundancy 30 http://ToBeAgile.com 15
- 16. 7/17/2012 Can non-identical code be redundant? 31 Can identical code be non-redundant? 32 http://ToBeAgile.com 16
- 17. 7/17/2012 Redundant intent 33 Code investment or debt 34 http://ToBeAgile.com 17
- 18. 7/17/2012 Pathologies of redundancy 35 Encapsulated 3 36 http://ToBeAgile.com 18
- 19. 7/17/2012 What can be encapsulated? 37 What you don’t know… 38 http://ToBeAgile.com 19
- 20. 7/17/2012 …can’t hurt you 39 Encapsulate by policy 40 http://ToBeAgile.com 20
- 21. 7/17/2012 Optimization 41 Can you encapsulate it? 42 http://ToBeAgile.com 21
- 22. 7/17/2012 Many ways to encapsulate 43 Pathologies of poor encapsulation 44 http://ToBeAgile.com 22
- 23. 7/17/2012 Assertive 4 45 Assertive or inquisitive? 46 http://ToBeAgile.com 23
- 24. 7/17/2012 Object therapy 47 “With great state comes great responsibility” 48 http://ToBeAgile.com 24
- 25. 7/17/2012 Winston Churchill, Spiderman’s Uncle 49 Pathologies of inquisitiveness 50 http://ToBeAgile.com 25
- 26. 7/17/2012 Testable 5 51 Testability guides design 52 http://ToBeAgile.com 26
- 27. 7/17/2012 Pathologies of poor testability 53 Explicit 6 54 http://ToBeAgile.com 27
- 28. 7/17/2012 Good and bad coupling 55 Bad coupling 56 http://ToBeAgile.com 28
- 29. 7/17/2012 Coupling Type Interface Abstract Concrete 57 Coupling example Abstract Coupling Type Coupling Interface Coupling No Concrete Coupling 58 http://ToBeAgile.com 29
- 30. 7/17/2012 Pathologies of bad coupling 59 The six code qualities… 60 http://ToBeAgile.com 30
- 31. 7/17/2012 – Cohesive – non-Redundant – Encapsulated – Assertive – Testable – Explicit 61 …spells CREATE 62 http://ToBeAgile.com 31
- 32. 7/17/2012 Code qualities guide us 63 Thank You! We have just scratched the surface, to learn more: – Read my blog: http://ToBeAgile.com/blog – Follow me on Twitter (@ToBeAgile) – Attend my one of my Certified Scrum Developer trainings Public Certified Scrum Developer Essentials classes: – October 15 – 19, 2012 in Redwood City, CA Public Agile Software Developer Essentials classes: – December 10 – 14, 2012 Online (8:00 am-12:00 pm PT) Private classes available for groups of 8 or more developers – Learn more at http://ToBeAgile.com 64 http://ToBeAgile.com 32