Why can’t I seem to grasp interfaces?

by

Interfaces allow you to program against a “description” instead of a type, which allows you to more-loosely associate elements of your software.

Think of it this way: You want to share data with someone in the cube next to you, so you pull out your flash stick and copy/paste. You walk next door and the guy says “is that USB?” and you say yes – all set. It doesn’t matter the size of the flash stick, nor the maker – all that matters is that it’s USB.

In the same way, interfaces allow you to generisize your development. Using another analogy – imagine you wanted to create an application that virtually painted cars. You might have a signature like this:

public void Paint(Car car, System.Drawing.Color color)...

This would work until your client said “now I want to paint trucks” so you could do this:

public void Paint (Vehicle vehicle, System.Drawing.Color color)...

this would broaden your app… until your client said “now I want to paint houses!” What you could have done from the very beginning is created an interface:

public interface IPaintable{
   void Paint(System.Drawing.Color color);
}

…and passed that to your routine:

public void Paint(IPaintable item, System.Drawing.Color color){
   item.Paint(color);
}

Hopefully this makes sense – it’s a pretty simplistic explanation but hopefully gets to the heart of it.

More Related Contents:

  1. Interface vs Abstract Class (general OO)
  2. Interface vs Base class
  3. When to use an interface instead of an abstract class and vice versa?
  4. What does “program to interfaces, not implementations” mean?
  5. Why would I want to use Interfaces? [closed]
  6. When should one use interfaces?
  7. Why do we use Interface? Is it only for Standardization? [closed]
  8. What is the definition of “interface” in object oriented programming
  9. When to use mixins and when to use interfaces in Dart?
  10. When to use interfaces or abstract classes? When to use both?
  11. When to implement an interface and when to extend a superclass?
  12. What is an example of the Liskov Substitution Principle?
  13. What is polymorphism, what is it for, and how is it used?
  14. Difference between abstraction and encapsulation?
  15. How will I know when to create an interface?
  16. What is the exact problem with multiple inheritance?
  17. Is it possible to access struct fields from within a trait?
  18. How much work should be done in a constructor?
  19. Do/can abstract classes replace interfaces? [duplicate]
  20. Why “private” methods in the object oriented?
  21. What is the meaning and reasoning behind the Open/Closed Principle?
  22. Should you always Code To Interfaces In Java [closed]
  23. What is the real difference between “Bastard Injection” and “Poor Man’s Injection”
  24. Difference between value parameter and reference parameter?
  25. Differences between Proxy and Decorator Pattern
  26. interface as a method parameter in Java
  27. What is immutability and why should I worry about it?
  28. adapter-Any real example of Adapter Pattern [closed]
  29. Is it possible to extend a default method implementation of a trait in a struct?
  30. How much interfaces a class file can implement [closed]

Leave a Comment