borja / herocalf

Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.

Common duplication problems, and corresponding solutions are:

• If you have the same expression in different places: Extract expression to a method
• If you have the same method in different sub-classes: Extract method, and pull up field to the parent class
• If you have the same code in unrelated classes: Consider extracting the code to a new class, and injecting that class