Refactoring to SOLID Code
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The document outlines a user group meeting for emerging .NET developers focused on design principles and best practices in software development, specifically exploring the SOLID principles. It emphasizes the importance of good design, maintainability, and the need for refactoring code to adhere to these principles. Key topics include the Single Responsibility Principle, Open-Closed Principle, Liskov Substitution Principle, Interface Segregation Principle, and Dependency Inversion Principle.
Refactoring to SOLID Code
- 1. Emerging .NET Devs October User Group Meeting Design Principles & Practices Adil Ahmed Mughal Zubair Ahmed
- 2. Refactoring to SOLID Code Emerging .NET Devs
- 3. Session => Refactoring to SOLID Code What You must already know: - Object Oriented Programming Language such as Java, C++, C# - Professional Experience What You will learn today: - Good Practices - OO Principles Sponsors:
- 4. Speaker => Adil Ahmed Mughal Affiliations: Contact Information: [email protected] @adilamughal http://www.adilmughal.com
- 5. Agenda This is not a single side talk, its discussion! Promise me that you will raise hand when you have query? • How You Code Today? • What is Bad Design? • What would You Call a Good Design? • SOLID Principles!
- 6. How You Code Today? • Do you care about design principles or patterns? • Anti-patterns? • Is your code Agile? • Do you Refactor your code? • Is your code design bad or good?
- 8. Bad design is... Needless Rigid Complexity Needless Fragile Repetition Immobile Viscous
- 11. What would You Call a Good Design? • Reliability • Flexibility • Separations of Concerns • Reusability • Maintainability
- 12. SOLID Object Oriented Principles Introduced by Robert C. Martin in early 2000s
- 13. SOLID Principles • S – Single Responsibility Principle (SRP) • O – Open Closed Principle (OCP) • L – Liskov Substitution Principle (LSP) • I – Interface Segregation Principle (ISP) • D – Dependency Inversion Principle (DIP)
- 14. Single Responsibility Principle (SRP)
- 16. The Single Responsibility Principle "A responsibility is a reason to change, a class or module should have one, and only one, reason to change."
- 17. The Single Responsibility Principle • “There should never be more than one reason for a class to change.” • More responsibilities => More likelihood of change • Dijkstra’s SoC: separation of concerns • Applies on every level of code • Solves the naming dilemma
- 18. Trade Validator Trade Validator DB Trade What is wrong here: Changes if DB changes or Business Logic Changes
- 19. Refactored Trade Validator Trade Trade Validator Source Trade DB What's its job? Classes must have an identifiable single responsibility.
- 21. The Open-Closed Principle (OCP)
- 22. The Open Closed Principle “Software Entities (Classes, Modules, Functions, etc.) should be open for extension, but closed for modification”
- 23. The Open Closed Principle • Modules that conform to the open-closed principle have two primary attributes – Open For Extension • behavior of the module can be extended – Closed for Modification • The source code of such a module is inviolate • The normal way to extend the behavior of a module is to make changes to that module. How can these two opposing attributes be resolved?
- 24. OCP – Change behavior without changing code? • Abstraction is the key to achieve it Client Server Closed Client
- 25. OCP – Change behavior without changing code? Client Abstract Server Server Open Client
- 27. Liskov Substitution Principle (LSP)
- 28. Liskov Substitution Principle “Functions that reference a base class must be able to use objects of derived classes without knowing it."
- 30. Interface Segregation Principle (ISP)
- 31. Interface Segregation Principle “Clients should not be forced to depend upon interfaces that they do not use.” • Prefer small, cohesive interfaces to fat interfaces
- 33. Dependency Inversion Principle (DIP)
- 34. Dependency Inversion Principle “High level modules should not depend upon low level modules. Both should depend upon abstractions. “ “Abstractions should not depend upon details. Details should depend upon abstractions.”
- 35. Trade Validator Introduce stability High Level (Less Stable) with abstraction Trade Trade Validator Source Trade Low Level DB (More Stable)
- 36. Better Trade Validator Trade Validator <Interface> ITradeSource Trade DbTradeSource DB
- 37. Extensible Trade Validator <Interface> TradeValidator ITradeSource Trade DbTradeSource WSTradeSource DB Cloud
- 40. Actions => From Now On Learn, Practice and Make it your Habit Links: - ObjectMentor.com - Practices and Patterns on MSDN Books:
- 41. References • Combatting Software Entropy using Design Principles and Practices – Hammad Rajjoub – TechEd ME • Agile Principles, Patterns and Practices using C# by Robert.C.Martin • Special thanks for motivational poster images by NimblePros
- 42. Thank You! Refactoring to SOLID Code Emerging .NET Devs