refactor

Refuse Alternative Classes with Different Interfaces when two classes do similar things but with mismatched method names and signatures — sortBy() vs orderUsing(), valueOf() vs evaluate(). Apply Change Function Declaration, Move Function.

Apply Change Function Declaration when you see Mysterious Name, Long Parameter List, Alternative Classes with Different Interfaces. Function names match what they actually do; parameter lists carry only what the function needs, in the order callers expect.

Apply Change Reference to Value when you see Mutable Data. An object treated as a sharable record (with setters) becomes a value object — immutable, equal by content, replaced rather than mutated.

Apply Change Value to Reference when you see Duplicated Code. Duplicate copies of a logically-single entity collapse into one shared object that everyone references.

Apply Collapse Hierarchy when you see Lazy Element, Speculative Generality. A subclass that no longer differs meaningfully from its parent merges back in.