Composition Root

Only one location in an application should have any knowledge of dependency injection: the composition root. This is where classes are constructed when you are using Poor Man’s DI, or where interfaces and class mappings are registered when you are using an Inversion of Control container.

The ideal is for the composition root to be as close to the entry point of the application as possible. This allows you to bootstrap DI as soon as possible, gives you a recognized location to find the DI configuration, and helps you avoid leaking dependencies on the container throughout the application.

McLean Hall, Gary

See Also:

• Ambient Context

• Dependency Injection (DI)

• Dependency Inversion Principle (DIP)

• Inversion of Control (IoC)

• Relationship between Dependency Inversion, Dependency Injection, Inversion of Control and SOLID

• SOLID Design Principles

• The Dependency Rule