Clean Code Developer Red Grade

Learn the principles and practices of Clean Code Development.

Transcript

1. Clean Code Developer A way to better code Session 01 https://github.com/mp911de/CCD Donnerstag, 18. Juli 13
2. Agenda • CCD Overview • Red Grade Donnerstag, 18. Juli 13
3. So, why is clean code important? Donnerstag, 18. Juli 13
4. You are the next on someone else‘s code Donnerstag, 18. Juli 13
5. You have to fix bugs Donnerstag, 18. Juli 13
6. Grade • 7 Grades • Make your progress visible • 0. Black: Interested in CCD • 1. Red: First Steps • 2. Orange: Steady Improvement • 3. Yellow: Intermediate • 4. Green: Productivity and Automation • 5. Blue: Test first, concepts • 6. White: Clean Code Developer Donnerstag, 18. Juli 13
7. Red Grade Donnerstag, 18. Juli 13
8. Red Grade • Principles • Don‘t Repeat Yourself (DRY) • Keep it simple, stupid (KISS) • Beware of optimization! • Favor Composition over Inheritance (FCoI) • Practices • Boy Scout Rule • Root Cause Analysis • Use a source code management system • Apply simple refactoring patterns • Reflect daily Donnerstag, 18. Juli 13
9. Don‘t Repeat Yourself (DRY) • Every duplicate causes effort and the need of maintenance • More code = more complexity • Reuse where possible double rate1 = calculateRate(1, 12); double rate2 = calculateRate(2, 24); double rate3 = calculateRate(3, 36); double rate4 = calculateRate(10, 120); Donnerstag, 18. Juli 13
10. Keep it simple, stupid (KISS)¶ • Life is simple – keep your code simple • A genius is result = not(xor(bithackA, bithackB)) and not a = !A ^ B; • More code is sometimes better to understand • Don‘t let your method names lie public String toString() { if (im == 0) return Double.toString(re); if (re == 0) return im + " I"; if (im < 0) return re + " - " + (-im) + " I"; return re + " + " + im + " I"; } Donnerstag, 18. Juli 13
11. Beware! Optimization! • Premature optimization is the root of a lot evil • Don‘t try to optimize for 2% performance, to get 5ms one-time performance • Improving performance by 500% to reduce runtime by days or weeks is something different Donnerstag, 18. Juli 13
12. Optimization Rules • Rule 1: Don't do it. • Rule 2 (for experts only): Don't do it yet. Donnerstag, 18. Juli 13
13. Favor Composition over Inheritance (FCoI) • Loose coupling • Easier testability • Easy reuse • Super-Classes in between are strong coupled in both directions Donnerstag, 18. Juli 13
14. Boy scout rule • Leave your place cleaner than you entered it • Clean up the code around your changes • Small cleanups – huge effect • Rotten code starts also small – if no one cares • But you care! Donnerstag, 18. Juli 13
15. Root Cause Analysis • You better know the cause of something (bug, feature) • No knowledge leads to wrong conclusions • Wrong conclusion • wrong implementation • Bug • Don‘t cure symptoms else your patient dies • Knowledge about the inner voodoo Donnerstag, 18. Juli 13
16. Use a SCM Need arguments? Donnerstag, 18. Juli 13
17. Apply simple refactoring patterns • Extract Method • Rename a Method/Class • Move a Method/Class • Think about the Boy scout rule • Code Examples https://github.com/mp911de/CCD Donnerstag, 18. Juli 13
18. Reflect daily • Measure your improvement • If you don‘t plan it, you don‘t do it • What have I done today? • What can I improve? • What do I want to try tomorrow? Donnerstag, 18. Juli 13
19. Image Credits Table of Contents: © by Michael Kappel http://michaelkappel.com Bands: © by Alexander Herzog Computer Geeks: Adam Breckler Blue Screen: Anders Rune Jensen Cable Chaos: Stefano Liboni Donnerstag, 18. Juli 13