Summary  
Composition uses object containment and delegation to build complex functionality by combining independent components instead of using rigid inheritance hierarchies. Dependency injection techniques (constructor and setter) govern how components are provided, balancing flexibility, safety, and testability.

General domain of usage  
Object-oriented software architecture

Composition focuses on building complex objects by combining simpler, independent components.

Instead of relying on inheritance, which creates rigid hierarchies, composition allows classes to collaborate through contained objects. This approach makes systems more **flexible**, **modular**, and **easier to maintain**, since components can be replaced or extended without breaking the entire structure.

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A few pitfalls to watch for when using composition are creating **god objects** that collect too many components and become difficult to manage, **leaking component APIs** through the outer class instead of keeping a clean interface, and introducing **hidden coupling** when components depend too much on each other's internal details.


What is a common risk when using composition that can make the design harder to maintain?

Learn how to build clean, secure, and scalable applications with Object-Oriented Programming in Python. Cover the fundamentals of classes and objects, then moves into advanced concepts such as inheritance, composition, polymorphism, and encapsulation. With clear explanations and practical examples, you'll develop the ability to design Python programs that are powerful, maintainable, and ready for real-world use.

Learn the core building blocks of object-oriented programming in Python. This section covers classes, objects, methods, and variables, giving you a solid base to understand how OOP organizes and structures code.

Explore how classes can share and extend functionality. You'll learn different inheritance patterns, from simple hierarchies to multiple inheritance and abstract classes, and see how they enable code reuse and scalability.

Discover how to build flexible systems by combining objects. Instead of relying only on inheritance, you'll see how composition lets you assemble behaviors in a modular, adaptable way.

Understand how different objects can share a common interface while behaving in their own way. This section shows how method overriding, interfaces, and protocols make your code more dynamic and reusable.

Learn how to safeguard internal data and control access to class attributes. You'll explore private attributes, getters and setters, and data-hiding techniques that keep your classes secure and maintainable.

Core Principles of Composition