Clean Architecture & Error Handling

Transcript

1. Clean Architecture & Error Handling Ahtsham Abbasi Senior Android Developer @ Mobiquity Consultant @ Rabobank mobiquity
2. Agenda 1. Clean Architecture 2. Domain Layer 3. Conclusion
3. #1 Clean Architecture What’s all the fuss about?
5. Why Architecture?
6. Why Clean Architecture? • Decouples the external components
7. Why Clean Architecture? • Decouples the external components • Works with other architectures like MVP, MVC, MVVM
8. Why Clean Architecture? • Decouples the external components • Works with other architectures like MVP, MVC, MVVM • Framework independent
9. What is Clean Architecture?
10. What is Clean Architecture? Clean code
11. What is Clean Architecture? Clean code
12. What is Clean Architecture? Clean code Onion arch. + Hexagonal arch.
13. What is Clean Architecture?
14. Flow of Control
15. Flow of Control Use Case Controller DB IoC
16. Number of layers
17. Layers Entities Use Cases Repositories View Models User Interface Database Rem ote API
18. Frontend app • Outer most circle • Notifications code • Cookies • Displaying content
19. Backend app • Outer most circle • Database code • Auth library • 3rd party services
20. Models Each layer must have its own models.
21. Dependency Injection Koin, Guice, Spring
22. #2 Domain Layer Implementation and error handling
23. Domain Layer
24. Components of Domain Layer • Use cases
25. Components of Domain Layer • Use cases • Models
26. Components of Domain Layer • Use cases • Models • Interfaces
27. Use Cases
33. Structuring a Use Case • Scope
34. Structuring a Use Case • Scope • Structure
35. Structuring a Use Case • Scope • Structure • Inputs / Outputs
36. Outputs • Requirement • Exhaustive output • Easy to learn • Easy to scale
37. Outputs • Requirement • Exhaustive output • Easy to learn • Easy to scale • Different options considered • Kotlin Try • Monadic outputs • Arrow-Kt • Sealed classes
38. Example
39. Invocation
40. Pitfalls to avoid
41. Pifalls to avoid • Returning nulls
42. Pifalls to avoid • Returning nulls • Wrapping non-exhaustible data in outputs
43. Pifalls to avoid • Returning nulls • Wrapping non-exhaustible data in outputs • Callbacks
44. Pifalls to avoid • Returning nulls • Wrapping non-exhaustible data in outputs • Callbacks • Exceptions
45. Pifalls to avoid • Returning nulls • Wrapping non-exhaustible data in outputs • Callbacks • Exceptions • Base classes
46. Other Layers Entities Use Cases Repositories View Models User Interface Database Rem ote API • Separate models • Aggregate outputs • Avoid exceptions
47. #3 Conclusions Learnings so far
48. Is it a good architecture for me?
49. It is for you, if you want to.. • Manage complex and scaling business requirements
50. It is for you, if you want to.. • Manage complex and scaling business requirements • Decouple the external components
51. It is for you, if you want to.. • Manage complex and scaling business requirements • Decouple the external components • Share business logic across platforms
52. It is for you, if you want to.. • Manage complex and scaling business requirements • Decouple the external components • Share business logic across platforms • Increase testability
53. It is for you, if you want to.. • Manage complex and scaling business requirements • Decouple the external components • Share business logic across platforms • Increase testability • Have a framework independent architecture
54. Drawbacks
55. Drawbacks • Code duplication • Boilerplate code • Learning curve • Not ideal for smaller projects
56. Final thoughts
57. Resources • Clean Architecture Book by Robert C. Martin • https://blog.cleancoder.com/uncle-bob/2012/08/13/the-clean-architecture.html • https://elizarov.medium.com/kotlin-and-exceptions-8062f589d07 • https://pusher.com/tutorials/clean-architecture-introduction/
58. Thank you! Ahtsham Abbasi ahtabbasi@gmail.com https://www.linkedin.com/in/ahtabbasi/ mobiquity