refactoring-patterns

Safe refactoring of long methods requires applying one-at-a-time, behavior-preserving transformations like Extract Function. You must identify specific code smells, apply a mechanical change from a defined catalog, and validate the result by re-running tests immediately after each step.

Replace Conditional with Polymorphism is used to fix code smells when you have complex conditional logic that varies by type. This refactoring moves conditional behavior into subclasses, reducing duplicated logic and simplifying the main method body while preserving observable behavior.

The best way to reduce Feature Envy and Data Clumps is to identify these code smells and map them to targeted transformations. Extract Function moves behavior to the correct object, while replacing primitive obsessions with proper classes gradually eliminates data clumps.

To extract a function from a God Class, use the Extract Function refactoring pattern with mechanical guardrails. Move the targeted logic step-by-step, ensuring behavior preservation by validating the transformation against your existing test suite immediately after each extraction.

Running tests after every single refactoring step is required because transformations must be behavior-preserving. Validating each isolated change immediately catches structural errors before they compound, ensuring the sequence of catalog-applied refactorings maintains the original observable behavior.

Yes, you can inline variables to simplify duplicated logic. Inline Variable is a valid catalog transformation that replaces temporary variables with their direct values, reducing unnecessary indirection and making subsequent refactorings to eliminate duplicated logic easier to apply.