Clean Code Developer Orange Grade

Learn the principles and practices of Clean Code Development. This is the second session in the Clean Code Development track. Go on with the next level and dig into Clean Code.

Transcript

1. Clean Code Developer A way to better code Session 02 https://github.com/mp911de/CCD Freitag, 2. August 13
2. Agenda • Orange Grade Freitag, 2. August 13
3. Orange Grade Freitag, 2. August 13
4. Orange Grade • Principles • Single Level of Abstraction (SLA) • Single Responsibility Principle (SRP) • Separation of Concerns (SoC) • Source Code Conventions • Practices • Issue tracking • Automated integration tests • Read, read, read • Reviews Freitag, 2. August 13
5. Single Level of Abstraction • A line of code has an abstraction-level • if/switch/for • getProperty() • publish() • Keep one method on one level • Improves readability and understandability Freitag, 2. August 13
6. Violation of Single Level of Abstraction Freitag, 2. August 13
7. Single Level of Abstraction after Refactoring Freitag, 2. August 13
8. Single Level of Abstraction wrap-up • Top-Down-Design • Main control routine • Subroutines • That guys which do something • Look at the newspaper: Headline, Sub-Header, Content Freitag, 2. August 13
9. Single Responsibility Principle • There is no more than one reason to change a class • Responsibility is • Parsing HTML/XML • Generating a data transfer object • Wrapping external libraries • Bad Example: Building HTML, pushing it via FTP and sending a mail in one class • Design and divide your code by domains (what a unit is responsible for) Freitag, 2. August 13
10. SRP Violation Freitag, 2. August 13
11. SRP after Refactoring Freitag, 2. August 13
12. Separation of Concerns • Concerns encapsulate multiple responsibilities • A responsibility belongs to one concern • Encapsulation • Demands a definition what exactly a code unit/module is responsible for Freitag, 2. August 13
13. Concerns are • Logging • Transaction Management • Security • Caching Freitag, 2. August 13
14. Concerns wrap-up • Business logic has no infrastructure/resource accessors • Business logic may produce logging but does not care about log pattern processing/ logfiles Freitag, 2. August 13
15. Source Code Conventions • Everybody is individual – else we are Borg • Commit on naming and comments • Process of max. 5 minutes int length; int len; int l; int lengthMM; int laenge; function Price() function getPrice() Function getGrossPrice() Freitag, 2. August 13
16. Issue Tracking • Master of chaos – everything is random • Enclose your work within a context • Trace what you‘ve done and use issue/ticket no. in your SCM commit message • SCM history tells hints at a context Freitag, 2. August 13
17. SCM Horror 512545 2012-01-02 13:37:00 Derp. Fix missing constant post rename 512545 2012-01-02 13:37:00 lots of changes after a lot of time 512545 2012-01-02 13:37:00 Committing fixes in the dark, seriously, who killed my power!? 9533 2012-05-23 16:45:51 That last commit message about silly mistakes pales in comparision to this one 9363 2012-05-15 15:11:51 Minor updates 9131 2012-05-09 16:01:53 totally more readable 9131 2012-05-09 16:01:53 QuickFix. Freitag, 2. August 13
18. Automated Integration Tests • Test first: Life insurance • Unit Tests: Test your production Code • Integration Test: Test with partial/full integration of databases, remote systems • Depend on environment • Be careful on QA/production systems • Repetitive task: Why doing it manually, automate it! Freitag, 2. August 13
19. Read, Read, Read • Read Code • Read Books • Read Blogs • Read about techniques to improve yourself and your code Freitag, 2. August 13
20. Reviews • Two see more than one • Increase quality, not being inspected • Prevent bugs • Cross check: Does your peer share the same opinion • Pass/Gather knowledge • Code-/Condept-Reviews • Pair Programming Freitag, 2. August 13
21. Image Credits Table of Contents: © by Michael Kappel http://michaelkappel.com Bands: © by Alexander Herzog Freitag, 2. August 13