The Clean Architecture is a software architecture proposed by Robert C. Martin (better known as Uncle Bob). This architecture is similar to the Onion-Hexagonal-DCI-Architecture proposed by their respective authors. The base of this architecture is to follow and obey rules of the 'Dependency Rule'.
The Clean Architecture is proposed by Robert C. Martin, also known as Uncle Bob. This architecture is similar to the Onion, Hexagonal, Screaming, and DCI architectures. Though these architectures all vary somewhat in their details, they are very similar. They all have the same objective, which is the separation of concerns. They all achieve this separation by dividing the software into layers.
Robert C. Martin, The Clean Architecture, 2012
The foundation layers of The Clean Architecture are:
- Entities (Enterprise Business Rules)
- Use cases (Application Business Rules)
- Interface Adapters
- Frameworks and Drivers.
The rules are driven by The Dependency Rule, which states that:
...source code dependencies can only point inwards. Nothing in an inner circle can know anything at all about something in an outer circle. In particular, the name of something declared in an outer circle must not be mentioned by the code in the an inner circle. That includes, functions, classes. variables, or any other named software entity.
Finally, when obeying this rule and using this architecture it is proposed that:
By separating the software into layers, and conforming to The Dependency Rule, you will create a system that is intrinsically testable, with all the benefits that implies.
