Knowledge · Anti-Patterns

Smell Repeated Switches

Code smell indicating repeated switch/case logic across the codebase (updated terminology from Switch Statements)

Impact

In the first edition, any switch statement was suspect. With languages supporting switch on strings and first-class functions, the blanket advice is no longer valid. The problem with repeated switches is that whenever you add a clause, you must find all the switches and update them. Polymorphism provides an elegant way to handle this by ensuring additions only require a new class.

Symptoms

In the first edition, any switch statement was suspect. With languages supporting switch on strings and first-class functions, the blanket advice is no longer valid. The problem with repeated switches is that whenever you add a clause, you must find all the switches and update them. Polymorphism provides an elegant way to handle this by ensuring additions only require a new class.

Source

Martin Fowler — Refactoring: Improving the Design of Existing Code, 2nd