Code Smell 35 — State as Properties

When an object changes its state the best solution is to change the attribute, isn’t it?

Photo by Tom Crew on Unsplash

Problems

• Mutability
• Attributes polluting
• Setters

Code Smell 28 — Setters

Solutions

1. Model states as mathematical set inclusion.
2. State is accidental, take it away from the object.

Examples

• State diagrams

Sample Code

Wrong

Right

Detection

If we want to be extreme, we should consider every setter to be a potential state change. Linters can warn us. But we might end up getting too many false positives.

Exceptions

• Over Design
• Performance issues (if a serious benchmark supports it).

Code Smell 20 — Premature Optimization

Tags

• Mutation

Conclusion

This technique is very elegant but can lead to over design. For example changing a visual component its color should be a counterexample to this smell.

We should be aware and very caution like with any other smell.

They are hints and not rigid rules.

Relations

Code Smell 28 — Setters

More info

The evil powers of mutants

First make the change easy (warning: this might be hard), then make the easy change.

Kent Beck

Software Engineering Great Quotes

This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code