Template Method

Template Method: base defines the skeleton, subclass fills a step

Problem: several variants share the same overall flow but differ in one or two steps.

PawWalk scenario: a report generator whose run always does header, body, footer. Each report type overrides only body.

The base method calls overridable methods; subclasses override just the varying step. (In Ruby you could also inject a block — but the classic template method is a clean fit when the skeleton is fixed.)