OO Design Principles

Here are some important principles of Object Oriented Design

   
• Identify the aspects of your application that vary and seperate them from what stays the same.
   
• Take what varies and encapsulate it so it won't affect the rest of the code.
   
• Program to an interface, not an implementation.
   
• Favour composition over inheritance.
   
• Strive for loosely coupled designs between objects that interact.
   
• Classes should be open for extension but closed for modification.
   
• Depend on abstractions, do not depend on concrete classes.
   
• Talk only to your immediate friends.
   
• A class should have only one reason to change.