oop

Association & Composition

Composition builds complex objects by combining simpler ones through 'has-a' relationships, as opposed to inheritance's 'is-a' relationships. Like how a car is composed of an engine, transmission, and wheels — rather than inheriting from Engine — composition creates flexible, swappable designs. This avoids the fragile base class problem and deep inheritance hierarchies.

Use Cases

•Building a notification system by composing channel, formatter, and throttler components
•Creating game characters by mixing in abilities (fly, swim, attack) rather than a rigid class tree
•Constructing HTTP clients by injecting auth, retry, and logging middleware
•Assembling report generators from data source, transformer, and renderer components

Implementation

Output

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