Clean Architecture

By Yohan

Transcript

2. Clean Code - quick summary • Naming • Small functions • Meaningful comments • Data abstraction • Error Handling • TDD(Unit Tests) • Building Systems
4. Goals At working at module level, software structure should • Tolerate changes • Easy to understand • Basic components for reuse
5. Our Enemies • Rigidity - difficult to change • Fragility - easy to break • Immobility - difficult to reuse • Viscosity - resistance against making changes
6. SOLID Principles • Single Responsibility • Open-closed • Liskov substitution • Interface segregation • Dependency Inversion
7. Single Responsibility Principle (SRP) • A module should be responsible to one, and only one, actor
8. SRP: Violation Employee -regularHours +calculatePay +reportHours +save Roy John Zune
9. SRP: Solution Employee Facade +calculatePay +reportHours +save PayCalculator +calculatePay HourReporter +reportHours EmployeeSaver +save
10. Open-closed Principle • Open for extension but closed for modification • Example with inheritance ◦ Bad ◦ Good
11. Liskov Substitution Principle • If for each object o1 of type S, there is an object o2 of type T, such that, for all programs P defined in terms of T, the behavior of P is unchanged when o1 is substituted for o2, then S is a subtype of T
14. LSP Violation Rectangle +setHeight +setWidth Square +setSides User
15. Interface Segregation Principle (ISP)
16. ISP Violation Ops +ops0 +ops1 +ops2 User0 User1 User2
17. Dependency Inversion Principle • Source code should interact with abstractions, not concretions • Stable vs volatile concrete elements
18. Takeaways • Consider actors in the system • Keep options open with layers • Interact with abstractions over details