Perth Code Dojo 3

Inheritance vs composition

Transcript

1. Perth Code Dojo 3 @willwebst #CodeDojo
2. Check-In ➔ Your name ➔ What you do (at work) ➔ A random fact about yourself
3. Code Dojo Format A Coding Dojo is a coding session centered around a programming challenge. The dojo provides a safe place to learn and experiment away from the pressures of business delivery. All programmers of varying skill levels meet as equals to learn and share.
4. Software Craftsmanship We were all rookies once Sharing of experiences Key concepts, new audience
5. Dojo Rules ➔ Paired Programming ➔ Simple Design ➔ Test Driven Development ➔ Refactoring
6. XP Practices ➔ Paired Programming ◆ A better design ◆ Collective code ownership ◆ Improved quality / less defects ◆ High standards ◆ Focus / A pair is harder to distract
7. Pomodoro ➔ Pomodoro Technique ◆ 25 mins on, 5 mins off ◆ http://tomatoi.st/perthcodedojo ➔ Four iterations
8. Retro & Pizza Closing with Pizza and a mini retrospective ➔ Share solutions on the big screen ➔ Discuss challenge / approach ➔ Feedback on the dojo
9. Polite Notice Please respect each others commitment. During a Pomodoro. ➔ No Facebook ➔ Mobile phones ➔ Etc.
10. Have Fun! Most importantly have fun! ➔ Drinks are available - help yourselves
11. Virtual garden!
12. Objective Composition and Inheritance What’s the difference? When to use?
13. Objective Inheritance for: ◦ versioning / commonality ◦ keeping state ◦ not forcing implementation - can stick with base
14. Objective Composition for: ◦ Applied to many disparate objects ◦ Has-a concept ◦ Polymorphism Liskov substitution principle ◦ Breaking changes
15. Create a basic garden Dimensions (50 metres x 10 metres) Soil type = clay Last watered Positional (X / Y) 1 x trees 2 x flowers
16. Begin! 25 mins
17. Stop! 5 mins
18. Extend Add a Mulch method Once called will mulch all applicable items
19. Begin! 25 mins
20. Stop! 5 mins
21. Second garden type Japanese Garden Dimensions (80 metres x 20 metres) Soil type = silt Positional (X / Y) 1 x ornate bridge 2 x trees
22. Begin! 25 mins
23. Stop! 5 mins
24. Third garden type Modern Low Maintenance Dimensions (20 metres x 12 metres) Soil type = na Area covered 1 x Artificial Lawn
25. Begin! 25 mins
26. Stop! 5 mins
27. Mini Retro How would you refactor to improve the design? Discuss when to apply inheritance for re-use? Any real examples where you have felt inheritance pain?
28. Bring a friend
29. Thank you sponsors! Code - http://github.com/burlistic Slides - http://speakerdeck.com/burlistic @willwebst