Code Smell 31 - Accidental Methods on Business Objects

Adding persistence, serialization, displaying, importing, exporting code to an object bloats its protocol and brings coupling.

Problems

• Readability

• Coupling

• Maintainability

Solutions

1. Keep your objects clean.

2. Decouple business objects.

3. Separate accidental concerns: Move Persistence, Formatting, Serialization to special objects.

4. Keep essential protocol using bijection.

Examples

• Persistence

• Identifiers

• Serialization

• Formatting

Sample Code

Wrong

Right

Detection

It is difficult (but not impossible) to create linting rules based on naming and hinting for suspect names.

Exceptions

• Some frameworks force us to inject dirty code in our objects. (For example identifiers).

We should try to use better languages/frameworks.

Tags

• Declarative

Conclusion

We are very used to see business objects polluted. This is normal. We need to reflect on the consequences and coupling from these designs.

Credits

Photo by Robert Bye on Unsplash

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Simple things should be simple, complex things should be possible.

Alan Kay