gof-strategy

One-line summary

Encapsulate each member of a family of algorithms behind a common interface and let the client compose the one it needs at runtime — instead of hardcoding the algorithm or branching on a type flag.

When to use this skill

• A class has a branching switch/if on a "type" field that selects between alternate algorithms (sort orders, pricing rules, validation strategies).
• Subclassing has been used to vary one piece of behavior, leading to a combinatorial explosion of classes.
• The set of algorithms is expected to grow.
• Two classes share most behavior but differ in a single dimension (e.g., MallardDuck and RubberDuck differ only in how they quack and fly).

When NOT to use this skill

• Only one algorithm exists and no second one is in sight — adding the indirection is YAGNI.
• The varying behavior involves a sequence of steps with mostly identical structure — that's gof-template-method.
• The variation is what gets composed not how it computes — that's often gof-decorator.

Core content