1.
#comdaybe
Object Calisthenics
Practices for Writing Object-Oriented
Aviva Solutions
Dennis Doomen

2.
Object…what?
Object Calisthenics
Object..ˌka-ləs-ˈthe-niks

3.
Like this?

4.
“…9 rules of thumb that will help push
your code into good object-oriented
shape...”
Jeff Bay

5.
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

6.
demo
One level of indentation per method
Rule 1

7.
demo
One dot per line
Don’t use the else keyword
Rules 2 & 5

8.
demo
Wrap all primitives and strings
…a.k.a. first-class types
Rule 3

9.
demo
First-class collections
Rule 4

10.
Choose names carefully
…not too short
…and…not too long
…contextual
Rule 6

11.
Keep all classes small
…a.k.a. Single Responsibility Principle
Rule 7

12.
No more than two instance variables
Rule 8

13.
demo
No properties
Rule 9

14.
demo
…no protected properties
…test data builders
…more refactoring
Final result

15.
Q&A

16.
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)

17.
Thank you!
Object Calisthenatics