Dependency Injection - Wikipedia
Dependency Injection is a design pattern used in object-oriented programming. It is a technique where the dependencies of a class are injected into it, rather than the class creating or managing its dependencies. This allows for loose coupling between classes and promotes better code reusability and testability.
In traditional programming, a class would create and manage its own dependencies. This can lead to tightly coupled code, making it difficult to modify or test individual components. With Dependency Injection, the dependencies are provided from the outside, typically through constructor injection or setter injection.
Constructor injection involves passing the dependencies as parameters to the constructor of the class. This ensures that the dependencies are available when the object is created. Setter injection, on the other hand, involves setting the dependencies using setter methods after the object is created.
By using Dependency Injection, classes become more modular and can be easily tested in isolation. It also allows for easier swapping of dependencies, as different implementations can be provided without modifying the class itself. This promotes the principles of separation of concerns and single responsibility.
Dependency Injection is widely used in frameworks and libraries for building scalable and maintainable applications. It helps to decouple the different components of an application and promotes code that is easier to understand, modify, and test.