Code Smell 60 — Global Classes

Classes are handy. We can call them and invoke them any time. Is this good?

Photo by Alfons Morales on Unsplash

Problems

• Coupling
• Classes are global unless we use Namespaces.
• Name polluting
• Static Methods
• Static Constants
• Singletons

Solutions

1. Use namespaces, module qualifiers or similar
2. Avoid namespace polluting, keep the Global names as short as possible.
3. Class single Responsibility is to create instances.

Sample Code

Wrong

Right

Detection

We can use almost any linter or create dependency rules searching for bad class references.

Tags

• Globals

Conclusion

We should restrict our classes to small domains and expose just facades to the outside. This greatly reduces coupling.

Relations

Code Smell 18 — Static Functions

Code Smell 17 — Global Functions

More info

Singleton: The Root of all Evil

Coupling: The one and only software design problem

Write shy code — modules that don’t reveal anything unnecessary to other modules and that don’t rely on other modules’ implementations.

Dave Thomas

Software Engineering Great Quotes

This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code