Anti-pattern: Re-use through inheritance

Thu, 19 Jul 2012 00:00:00 +0000

When I first started programming in object oriented languages I used inheritance to reduce code duplication. You know the deal - you have two classes that do the same sort of thing so you create an abstract superclass and extract the common code into methods in the superclass. Voilà. No more duplicated code.

But I was unwittingly creating an untestable codebase.

I have worked extensively with dependency injection containers over the last five years and have begun to rely on the clean code they facilitate. DI encourages loosely coupled classes and interface abstractions, so code re-use is typically achieved by extracting the common code into its own class and injecting that class as a collaborator.

Anti-Pattern on Craig Pardey

Anti-pattern: Re-use through inheritance