Solid as OOP abstraction
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The document outlines principles of Object-Oriented Programming (OOP) focusing on SOLID principles, which promote better software design and reduce technical debt. It discusses common code smells and design smells that indicate issues in OOP practices and offers guidelines for cleaner code. Key principles include single responsibility, open-closed, Liskov substitution, interface segregation, and dependency inversion.
Solid as OOP abstraction
- 1. SOLID as OOP abstraction Paweł Klimczyk Gemotial 2016
- 2. About me •Software engineer •Running Gemotial Software Studio •Co-organizer ofWrocNET •Blog: http://blog.klimczyk.pl •E-mail: pawel@klimczyk.pl •Twitter: @pwlklm •GitHub: pawelklimczyk
- 4. What is OOP ? •Abstraction •Encapsulation •Inheritance •Polymorphism
- 5. OOP (r)evolution •Simula 67, Smalltalk •Ada, Lisp •C#, Java
- 6. OOP bad habits- Code Smells • Duplicate Code • Long Method • Comments • Long Parameter List • Large Class • Switch Statements • Parallel Inheritance Hierarchies • Conditional Complexity • Combinitorial Explosion • Uncommunicative Name • Dead Code • Inconsistent Names • Temporary Field
- 7. OOP bad habits - Design Smells • Alternative Classes with Different Interfaces • Primitive ObsessionData Class • Data Clumps • Refused Bequest • Inappropriate Intimacy • Indecent Exposure • Feature Envy • Lazy Class • Message Chains • Middle Man • Divergent Change • Shotgun Surgery • Parallel Inheritance Hierarchies • Incomplete Library Class • Solution Sprawl
- 8. Technical debt trap •Hard to extend rotten code •The longer we wait to remove the smells, the more it will cost
- 9. SOLID – the beginning Michael Feathers Robert C.Martin Year ~2000
- 10. Occam's razor principle Occam's razor is a problem-solving principle devised by William of Ockham.The principle states that among competing hypotheses, the one with the fewest assumptions should be selected. Other, more complicated solutions may ultimately prove correct, but—in the absence of certainty—the fewer assumptions that are made, the better.
- 11. SOLID •Single Responsibility Principle (SRP) •Open-Closed Principle (OCP) •Liskov Substitution Principle (LSP) •Interface Segregation Principle (ISP) •Dependency Inversion Principle (DIP)
- 12. Single Responsibility Principle (SRP) A class or similar unit of code should have one responsibility only and, therefore, only one reason to change.
- 13. Single Responsibility Principle (SRP)
- 14. Open-Closed Principle (OCP) You should be able to extend a classes behavior, without modifying it.
- 16. Liskov Substitution Principle (LSP) Derived classes must be substitutable for their base classes.
- 17. Liskov Substitution Principle (LSP)
- 18. Interface Segregation Principle (ISP) Make fine grained interfaces that are client specific. Clients should not be forced to depend upon interfaces that they don't use.
- 19. Interface Segregation Principle (ISP)
- 20. Dependency Inversion Principle (DIP) Depend on abstractions, not on concretions. High level modules should not depend upon low level modules and abstractions should not depend upon details.
- 21. Dependency Inversion Principle (DIP)
- 22. Other principles •Keep It Simple Stupid (KISS) •You Ain’t Gonna Need It (YAGNI) •Don’t RepeatYourself (DRY)
- 23. References • http://objectmentor.com/Images/photo_feathers.jpg • http://upload.wikimedia.org/wikipedia/commons/thumb/e/ee/Robert_Cecil _Martin.png/220px-Robert_Cecil_Martin.png • http://www.butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod • SOLID examples: • https://msdn.microsoft.com/en-us/magazine/dn683797.aspx
- 24. Q&A
Editor's Notes
- #6: Ole-Johana Dahl and Kristen Nygaard