Inversion of Control is inverting the whole program flow so that a container manages all program dependencies. Instead of this, you can transfer your construction responsibilities to an IoC container. You can manually handle all of the initializations and injections, but this leads to intricate systems, which we try to avoid. How you do this “carrying away” and “re-introducing them” is the problem of managing dependencies. You carry away the complicated part from the code, and you re-introduce dependencies through other ways.

Delegating object initializations can reduce the stress of designing classes by taking care of complex operations. The dependency injection principle tells us that a class should receive its dependencies rather than instantiating them. Then, we have to ask these questions: How are these references constructed? Should we assemble these objects, or should others be responsible for instantiating them? What if instantiating a class is too complex, and we want to avoid spaghetti code? All these questions compose the problem set the Dependency Injection Principle tries to solve.īefore we proceed to the examples, we have to understand a few concepts about dependency injection. Other classes support our class by offering to do complex operations on our behalf of us.Ī class may have fields that refer to other ones. Like building a structure, we set up relations that are called dependencies between our blocks. In Object-Oriented Programming, we use classes to build complex architectures. Photo by Anthony DELANOIX on Unsplash IntroductionĮvery software program has fundamental building blocks.

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