Dependency Inversion Principle (DIP) is a software development principle that reduces coupling between code.
Robert C Martin explains DIP:
- High-level modules should not depend on low-level modules. Both should depend on abstractions.
- Abstractions should not depend on details. Details should depend on abstractions.
Consider if you have an object that calls another object. The higher level object is dependent on the lower level object; making changes to the lower level object may cause issues in the higher level object. Instead of implementing the code this way, both objects should depend on an abstraction.
To implement an abstraction, we can create an interface for our low level object, and then have each of the objects call the interface.