Tag Archives: DI frameworks

Dependency injection Containers are Code Polluters


Dependency injection Containers are Code Polluters

While dependency injection (aka, “DI”) is a natural technique of composing objects in OOP (known long before the term was introduced by Martin Fowler), Spring IoC, Google Guice, Java EE6 CDI, Dagger and other DI frameworks turn it into an anti-pattern.

I’m not going to discuss obvious arguments against “setter injections” (like inSpring IoC) and “field injections” (like in PicoContainer). These mechanisms simply violate basic principles of object-oriented programming and encourage us to create incomplete, mutable objects, that get stuffed with data during the course of application execution. Remember: ideal objects must be immutable and may not contain setters.

Instead, let’s talk about “constructor injection” (like in Google Guice) and its use with dependency injection containers. I’ll try to show why I consider these containers a redundancy, at least.