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Object Calisthenics
Practices for Writing Object-Oriented
Aviva Solutions
Dennis Doomen
Object…what?
Object Calisthenics
Object..ˌka-ləs-ˈthe-niks
Like this?
“…9 rules of thumb that will help push
your code into good object-oriented
shape...”
Jeff Bay
So who am I?
Principal Consultant
Aviva Solutions
Fluent Assertions
C# Coding
Guidelines
@ddoomen
TDD, DDD, BDD
Application Lifecycle
Management
Agile
XP
www.dennisdoomen.net
demo
One level of indentation per method
Rule 1
demo
One dot per line
Don’t use the else keyword
Rules 2 & 5
demo
Wrap all primitives and strings
…a.k.a. first-class types
Rule 3
demo
First-class collections
Rule 4
Choose names carefully
…not too short
…and…not too long
…contextual
Rule 6
Keep all classes small
…a.k.a. Single Responsibility Principle
Rule 7
No more than two instance variables
Rule 8
demo
No properties
Rule 9
demo
…no protected properties
…test data builders
…more refactoring
Final result
Q&A
Resources
• Example Code (original by Johan
Martinsson)
• Object Calisthenics (by Jeff Bay)
• C# Coding Guidelines (by me)
• www.dennisdoomen.net (by me…again )
• Agile Principles, Patterns, and Practices in
C# (by Uncle Bob)
Thank you!
Object Calisthenatics

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Object Calisthenics; Practices for Writing Object-Oriented C#