Object Calisthenics – 10 Steps to Better Software Design

Object calisthenics is a simple ruleset that, if applied correctly, should have a big effect on your designs. For the time being, follow these rules; we will discuss the principles behind them later on:

• Only one level of indentation per method
• Don't use the ELSE keyword
• Wrap all primitives and strings (wrap primitive types in classes)
• First-class collections (wrap collections in classes)
• One dot per line
• Don't abbreviate
• Keep all entities small
• No classes with more than two instance variables
• No getters/setters/properties
• All classes must have state

Object calisthenics does not give you anything new; on the contrary, it takes stuff away. Expect these rules/constraints to be challenging/frustrating if you have never used them before. Be strict for now – no exceptions! The time to bend the rules has not yet come.

Important

Pay extra attention to not...