This document discusses clean architecture, which aims to separate an application into distinct layers. The core application logic is separated from the user interface and database access. This improves testability and flexibility. Some benefits of clean architecture include excellent testability since each component can be tested in isolation, clearly defined separation of concerns, and flexibility to change parts of the application independently. However, there are also costs like increased complexity with more classes and data conversions between layers.

1. Clean architecture
Andrzej Bednarz
andbedwroc@gmail.com
https://github.com/andbed/clean-architecture
05.07.2014

3. A new project

4. Self testing software

5. Clean architecture

6. Demo
• Basic structure
• Input/output

8. Application Core
Source: Uncle Bob, http://blog.8thlight.com/uncle-bob/2011/11/22/Clean-Architecture.html

9. Controller -> Interactor
Source: Uncle Bob, http://blog.8thlight.com/uncle-bob/2011/11/22/Clean-Architecture.html

10. Controller <- Interactor
Source: Uncle Bob, http://blog.8thlight.com/uncle-bob/2011/11/22/Clean-Architecture.html

11. Source: Uncle Bob, http://blog.8thlight.com/uncle-bob/2011/11/22/Clean-Architecture.html

12. Traditional layered architecture

13. Clean architecture

14. Source: Uncle Bob, http://blog.8thlight.com/uncle-bob/2012/08/13/the-clean-architecture.html

15. Hexagonal Architecture

16. Summary

17. We are still on the way...

18. Excellent testability
Every component and layer could be tested in isolation

19. Clearly defined separation of concerns
Flexibility

20. Gradual architecture introduction

21. Lots of additional classes and interfaces
Lots of DTOs and conversions

22. Cost
Source: David Heinemeier Hansson, https://gist.github.com/dhh/4849a20d2ba89b34b201
Based on: Jim Weirich's "Decoupling from Rails"

23. Source: David Heinemeier Hansson, https://gist.github.com/dhh/4849a20d2ba89b34b201
Based on: Jim Weirich's "Decoupling from Rails"

24. Source: David Heinemeier Hansson, https://gist.github.com/dhh/4849a20d2ba89b34b201
Based on: Jim Weirich's "Decoupling from Rails"

25. Not new
Not only Java related
Not a rocket science
Not home-grown

26. References
http://blog.8thlight.com/uncle-bob/2012/08/13/the-clean-architecture.html
http://blog.8thlight.com/uncle-bob/2011/11/22/Clean-Architecture.html
http://blog.8thlight.com/uncle-bob/2011/09/30/Screaming-
Architecture.html
http://alistair.cockburn.us/Hexagonal+architecture
http://www.growing-object-oriented-software.com/
http://jeffreypalermo.com/blog/the-onion-architecture-part-1/
http://martinfowler.com/articles/is-tdd-dead/
https://groups.google.com/forum/#!forum/clean-code-discussion
http://en.wikipedia.org/wiki/Data,_context_and_interaction
http://andrzejonsoftware.blogspot.com/2013/12/the-four-architectures-that-
will.html
Object Oriented Software Engineering: A Use Case Driven Approach, Ivar
Jacobson, 1992

27. Examples
https://github.com/andbed/clean-architecture
http://obvious.retromocha.com/
https://github.com/michelchenrich/crudrefactorkata.git
https://github.com/lukasz-duda/ArchitectureSample
http://www.whitewashing.de/2012/08/13/oop_business_applic
ations_entity_boundary_interactor.html

28. Thank you!