How can you use design patterns to implement composition over inheritance in object-oriented programming?

The Strategy Pattern is how we implement the Open-Closed Principle (The O of SOLID). It works well with an Inversion of Control (IoC) framework, such as .NET and Angular. Instead of writing some behaviour (B) class C needs within C, you define it elsewhere: class E. You then let C compose B by adding B to C’s constructor. B is the Strategy. After that, you configure your IoC framework to provide (inject) E where B is needed. If you need to change the behaviour of B in the future, you can write it in a new class (N). After that, reconfigure the IoC framework to provide N for B instead of E. Viola! You’ve changed C’s behaviour without having to modify it. Note that C composed B. It didn’t inherit it.

Always a strategic challenge to choose the right design pattern. Always keep SOLID principles in mind while preparing thr class design. Rest all with fall in their righteous places.

To implement composition over inheritance using design patterns in object-oriented programming, you can utilize the "Decorator" or "Strategy" patterns. These patterns allow you to favor composition by assembling objects dynamically rather than relying on static inheritance hierarchies.

There are many patterns to use for this but adding detail for 2 Patterns. 1.Decorator Pattern The Decorator pattern enables you to dynamically add behaviour or responsibilities to objects. Instead of adding functionality through subclasses, you wrap things within other objects (decorators) that add or modify behaviour. This encourages code reuse while avoiding inheritance's inflexible class structures. 2. Strategy Pattern The Strategy pattern describes a family of algorithms, encapsulates them, and allows them to be interchanged. Classes include a reference to an interface or abstract class that defines the behaviour, rather than inheriting it from a superclass. At runtime, different implementations (strategies) can be exchanged.

To implement composition over inheritance using design patterns in object-oriented programming, you can utilize the "Decorator" or "Strategy" patterns. These patterns allow you to favor composition by assembling objects dynamically rather than relying on static inheritance hierarchies.

Really helpful and simple description. An important thing in this kind of structure is the protection against the cycle, that should take care during building or navigation.

Strategy, Adapter are life savers for me. I do love CQRS with Mediator and Specific generic repository with unit of work in .NET.

The Adapter pattern promotes flexibility by decoupling classes through composition rather than inheritance. This approach simplifies maintenance, allows for clearer responsibilities per class, and facilitates scalability. By encapsulating adapting behaviors in specific adapters, we ensure a streamlined and maintainable object-oriented design.

If you need a set of fixed patterns to design software, you're not in the field that fits your skills. If you can't compose using librairies w/o OO, you're impaired. Period. OO just adds more ceremonial low value code. Go find something else to do. ?? This is not a bureaucratic process.