Clean Architecture
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The document discusses Clean Architecture, an approach for building maintainable and testable code. It presents four main principles: 1) limit dependencies between modules, 2) introduce boundaries between modules, 3) have dependencies point towards abstractions, and 4) inject dependencies. The architecture separates entities, business rules, use cases, interfaces, and drivers/frameworks. This independent, layered structure makes the code independent of frameworks and databases, and easier to maintain and evolve over time.
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public class App {
...
static void main(String[] args){
...
dbConn = new MysqlConnection(...); // framework
view = new HTMLView(...); //framework
repository = new MysqlRepository(dbConn); // interface adapter
controller = new Controller(getRequest()); // interface adapter
presenter = new Presenter(view); // interface adapter
useCase = new ListOrders(controller, repository);
useCase.addPresenter(presenter);
useCase.run();
...
}
...
}](https://image.slidesharecdn.com/clean-architecture-181008154535/85/Clean-Architecture-35-320.jpg)
Clean Architecture
- 1. CLEAN ARCHITECTURE Flavius Ștef, Syneto Timișoara, Oct. 2018
- 2. CODING IS HARD ENOUGH ALREADY Programming language Libraries Front-end framework Back-end framework AWS or Azure sync vs async trees and graphs ML ...2
- 3. Why also bother with architecture? Layered, MVC, REST, Microservices... 3
- 4. TWO PHASES FOR EACH CODEBASE 4 Puberty MVP, 0.9beta, 1.0 Code familiarity Progress Maturity Value delivery Speed Quality Architecture matters the most here
- 5. ARCHITECTUREtries to solve an economic set of needs, not a technical one 5
- 6. Average codebase life: 10 years 6
- 7. SYNETO ARCHITECTURE NEEDS Steady Velocity In the marketplace High quality Limited margin for errors Easy onboarding Of new team members. Reuse components As we build new features Test automation To catch errors fast. Code readability Change code with confidence. 7
- 8. YOUR NEEDS? Reuse, automation, readability Security Scalability Velocity 8
- 9. CLEAN ARCHITECTURE By Robert “Uncle Bob” Martin Code maintenance and evolution 9
- 11. What gets in the way? 11
- 12. Dependencies 12
- 14. Encapsulation All related code should be in the same class/module. LIMIT DEPENDENCIES Cohesion All code in the same class/module should be related. 14 👍 👎
- 15. “every module or class should have responsibility over a single part of the functionality provided by the software, and that responsibility should be entirely encapsulated by the class. -- Wikipedia (SRP) 15
- 16. SRP 16 # $ %
- 17. MODULE LEVEL DEPENDENCY MANAGEMENT ▪ How do we group classes together? ▪ How do the dependencies point? ▪ Who creates the clases? 17
- 18. Big Ball of Mud HOW DO WE GROUP CLASSES? 18 MVC / MVVM / MVP Layered Controller Model View UI Business Database
- 19. PRINCIPLE #2Introduce boundaries between modules 19
- 20. Big Ball of Mud DEPENDENCIES 20 MVC / MVVM / MVP Layered Controller Model View UI Business Database
- 22. PRINCIPLE #3Dependencies point in the direction of the abstraction 22
- 25. 25 class InvoiceGenerator { private SMTPSender sender; public InvoiceGenerator() { sender = new SMTPSender(); } } // client InvoiceGenerator g = new InvoiceGenerator(); interface EmailSender { public void sendEmail(); } class SMTPSender implements EmailSender { ... } class AWSEmailSender implements EmailSender { ... } class CleanInvoiceGenerator { private EmailSender sender; public CleanInvoiceGenerator(EmailSender s) { sender = s; } } // client CleanInvoiceSender s = new InvoiceSender(new SMTPSender()); CleanInvoiceSender s = new InvoiceSender(new AWSEmailSender());
- 26. MAINTAINABLE CODE PRINCIPLES ▪ Limit dependencies ▪ Introduce boundaries between modules ▪ Dependencies point in the dir. of the abstraction ▪ Inject dependencies 26
- 27. 2. CLEAN ARCHITECTURE Putting it all together
- 28. CHARACTERISTICS 1. independent of frameworks 2. testable 3. independent of the UI 4. independent of the database 5. independent of any external agency 28
- 29. “your business rules don’t know anything at all about the interfaces to the outside world. -- R. Martin, Clean Architecture 29
- 30. 30 Entities “VAT of 19% will be applied to all sold items, except for books where VAT is 5%” “You cannot power off a powered off VM Enterprise Rules
- 31. 31 Entities Enterprise Rules Use Cases Application Rules “send a SMS to the client after we have successfully approved his meal order”
- 33. 33 Entities Enterprise Rules Use Cases Application Rules Web UI Devices DB Frameworks & Drivers
- 34. 34 Entities Enterprise Rules Use Cases Application Rules Web UI Devices DB Frameworks & Drivers Controllers Interface Adapters
- 35. 35 public class App { ... static void main(String[] args){ ... dbConn = new MysqlConnection(...); // framework view = new HTMLView(...); //framework repository = new MysqlRepository(dbConn); // interface adapter controller = new Controller(getRequest()); // interface adapter presenter = new Presenter(view); // interface adapter useCase = new ListOrders(controller, repository); useCase.addPresenter(presenter); useCase.run(); ... } ... }
- 37. 37 AN EXAMPLE
- 39. 3. FINAL WORDS A few tips and tricks and summary
- 40. TIPS Analyze the investment Clean architecture is not cheap 40 Use it with DDD and CQRS It maps nicely Don’t be too rigid Figure out which rules can be broken Spend time understanding the layers What should go in infrastructure, app and domain
- 41. CLEAN ARCHITECTURE IS ReadableTestable Reusable Evolvable
- 42. THANKS! Any questions? You can find me at: @flaviusstef flavius.stef@gmail.com slideshare.net/fstef 42