Interfaces in Action - The Art of Polymorphism

Understanding the importance of building loosely coupled software solutions powered by the art of the polymorphic behavior. Following the core concepts of object oriented paradigm can lead us towards the process of creating powerful functionalities in the spirit of increased flexibility, testability and extensibility.

Transcript

1. Interfaces in Action: The Art of Polymorphism
2. PLATINUM GOLD SILVER BRONZE MEDIA PARTNER SUPPORTING PARTNERS OUR PARTNERS
3. Ве молиме исклучете ги мобилните уреди Please turn off your mobile devices
4. Self-motivated software developer and future PhD in the field of bioinformatics. Latest technology addicted person with strong vision directed to the well - known real life challenges. Always open to learn and undertake upcoming modern technologies and development tools. Until now has worked in different companies as web and mobile software developer using Microsoft .NET framework and C# programming language. cekicmiodrag@gmail.com https://www.facebook.com/miodrag.cekic.94 miodrag9581
5. Agenda ▪ Class Hierarchy and Coupling ▪ Classes Relationships ▪ Interfaces in Action ▪ Wrap up
7. Class Hierarchy and Coupling • Class coupling • A measure on how one class is connected or dependent with another class/classes Application Class A Direct dependency Indirect dependency Class B Class C Class F Class D Class E Class G (Tight Coupling) (Loosely Coupling)
8. Class Hierarchy and Coupling Object Oriented Paradigm • Encapsulation • Abstraction • Inheritance • Polymorphism
9. Classes Relationships • Associations types Inheritance (Is-a relationship) Customer PremiumCustomer GoldCustomer Composition (Has-a relationship) Vehicle Engine Mechanism by which one class is allowed to inherit the code (fields and methods) of another class Mechanism by which one class is allowed to contain the another class
10. Media Storage Challenge…
11. Classes Relationships MediaStorage HardDrive (HD) FlashDrive (USB) OpticalDiscDrive (ODD) CompactDisc (CD) DigitalVertileDisc (DVD) • Inheritance
12. Classes Relationships • Composition MediaStorage - id: int - vendor: string - serial: string - size: float + openDrive(): void + read(): string + write(string): bool Deletable + delete(string): bool HardDrive (HD) CompactDisc (CD) Rewritable DigitalVertileDisc (RWDVD)
13. Classes Relationships • Composition over Inheritance MediaStorage CompactDisc (CD) HardDrive (HD) Inheritance Tightly Coupling
14. Classes Relationships • Composition over Inheritance Composition MediaStorage CompactDisc (CD) IMediaStorage CompactDisc (CD) Loosely Coupling
15. Interfaces in Action • First Things First: What is an Interface? • Structure with the definitions for a group of related functionalities • Container for declaration of the methods • Language construct like an abstract base class
16. Interfaces in Action • First Things First: What is an Interface? • Contract between itself and any class implementing it • Enables “Plug & Play” functionality • Analogy with agreement or blueprint
17. Interfaces in Action • From Composition to interface IDeletable MediaStorage + openDrive(): void + read(): string + write(string): bool Deletable + delete(string): bool HardDrive (HD)
18. Interfaces in Action • From Composition to interface IDeletable
19. Interfaces in Action • From Composition to interface IDeletable
20. Multiple Inheritance..??!
21. Interfaces in Action • Interfaces & Multiple Inheritance
22. Interfaces in Action • Interfaces & Multiple Inheritance Interfaces do NOT provide MULTIPLE INHERITANCE!
23. Interfaces in Action • WHY Interfaces? ✓ Extensibility ✓ Maintainability ✓ Testability • Building loosely coupled software applications in terms of improved:
24. Interfaces in Action • Dependency Injection Design Pattern • Constructor injection • Setter injection • Method injection
25. Interfaces in Action • Dependency on “concrete” objects new()
26. Encryption Demo Message Dispatcher
27. Interfaces in Action • DI on “concrete” objects leads to Tight Coupling
28. Interfaces in Action • Depend on abstractions, NOT concretions
29. Encryption Demo Logger Extension
30. Interfaces in Action Pluggable software components Design by contract
31. Interfaces in Action
32. Interfaces in Action POLYMORPHISM Polymorphism is the ability of an object to change behavior on runtime
33. But HOW can we TEST Interfaces…?
34. Interfaces in Action • Encryption Demo - Polymorphism.UnitTests • Mock mimics and isolates the behavior of a real object • Interfaces removes the dependencies and makes the code unit testable
35. Interfaces in Action • Encryption Demo - BUT still Tightly Coupling??? new()
36. Interfaces in Action • Encryption Demo - DI through Container REGISTER RESOLVE R-R Runtime Reflection
37. Interfaces in Action
38. Wrap Up ✓Understanding the importance of building loosely coupled software solutions powered by the art of the polymorphic behavior. ✓Interfaces as powerful language construct in the spirit of increased flexibility, testability and extensibility.
39. Thanks! Any Questions?