OO Basics

Components can be objects, variables, methods etc...

1. Abstraction - group together common components.
2. Inheritance - extend and gain components from a parent.
3. Polymorphism - entities that can take on multiple forms.
4. Encapsulation - restrict access to components that logically sit together.

OO Design Principles

1. Identify what varies and keep it from what stays the same.
2. Program to interfaces not implementations.
3. Favour composition over inheritance.
4. Aim for loosely coupled objects.

OO Patterns

1. Strategy - interchangeable algorithms.
2. Observer - publish/subscribe model.