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.
