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Franziska Sauerwein Software Craftswoman at Codurance LTD

Object Calisthenics

Improve your Object Oriented Design

As athlethes practice with higher constraints to excell in a competition, we too can practice our design skills by adhereing to seemingly extreme rules.

We will follow Jeff Bay's 9 rules of Object Calisthenics:

  • Use only one level of indentation per method
  • Don’t use the else keyword
  • Wrap all primitives and strings
  • Use only one dot per line
  • Don’t abbreviate
  • Keep all entities small
  • Don’t use any classes with more than two instance variables
  • Use first-class collections
  • Don’t use any getters/setters/properties
After a short introduction, participant will pair program in a object oriented language of their choice for two iterations.

Depending on their prior experience, the rules can be tackled step by step.
In between, we will have time to share and discuss our findings.


I realise this workshop is not new material, but might be useful for some conference attendees who have not had it anyways. I have run it on various occasions and I'd be happy to run it again.

Half of the participants will need a laptop with a ready-to-get-to-work IDE.