Decorator

The Decorator pattern enables us to change the behavior of an object by hiding the contained functions and adding new functionalities around it. It is also a common way to avoid the limits of single inheritance by multiple interface implementations (composition over inheritance).

Usage

This pattern finds its typical use in framework development because it enables the layering of functionalities around a core service.

Examples

• Caching in HTTP services can be implemented as a decorator pattern by wrapping the http client within a client that analyzes the requested url and prepares a response
• Logging and instrumenting methods can be implmented as a decorator that covers the interactions once for all the possible activities.