First Look at Clean Architecture
Introduction
Clean Architecture is a comprehensive software design methodology renowned for its flexibility, sustainability, and emphasis on testability. At its core, it advocates for the separation of concerns, ensuring that each layer of the software operates independently, facilitating easier maintenance and scalability.
By adhering to the SOLID principles, Clean Architecture promotes a codebase that is robust, adaptable, and inherently resistant to unforeseen changes. Moreover, its careful structuring minimizes dependencies between components, fostering a modular and easily maintainable system that can evolve with changing requirements and technological advancements.
Layers
- Entities: It is the inner part that contains entities and core business logic. Entities contain important concepts and data involved in business processes. It represents business domain-specific entities and the relationships between them. Entities don’t depend on anywhere or anything.
- Use Cases: This layer includes use cases. It contains the rules and logic that relate to the application’s design and behavior. In this layer, requests are received, and processed and appropriate responses are generated. It transfers requests from the user interface to the business logic and is responsible for transmitting the results to the user.
- Interface Adapters: It consists of a collection of adapters that translate data from the format most appropriate for the use cases and entities to the format most convenient for an external agency such as a database or the web.
- Framework and Drivers: The frameworks and tools that structure up the outermost layer often include the database, the web framework, etc.
Why?
➡️ The architecture is designed to be framework-agnostic, meaning it doesn’t rely on specific software libraries for its functionality. This flexibility allows frameworks to be used as tools rather than being restricted by their limitations.
➡️ The system’s business rules can be tested independently of any external elements like the user interface, database, or web server.
➡️ Changes to the UI can be made easily without impacting the rest of the system. For instance, transitioning from a web interface to a console interface wouldn’t require alterations to the core business rules.
➡️ The choice of database is interchangeable without affecting the business rules. Whether using Oracle, SQL Server, MongoDB, or another database system, the functionality remains intact.
➡️ The business rules are completely isolated from external influences, operating independently without any knowledge of or reliance on external agencies or systems.
References
- https://romanglushach.medium.com/understanding-hexagonal-clean-onion-and-traditional-layered-architectures-a-deep-dive-c0f93b8a1b96
- https://medium.com/oolooroo/navigating-the-maze-of-modern-architectures-comparing-and-contrasting-leading-software-dcec9b68fc87
- https://blog.cleancoder.com/uncle-bob/2012/08/13/the-clean-architecture.html
