Patterns Reusable solutions to common object-oriented programming problems When given a programming problem, re-use an existing solution. Gang of Four Patterns

Simple Elegant Solutions Design patterns capture solutions that have developed and evolved over time – They aren't the designs people tend to generate initially. – They reflect untold redesign and recoding as developers have struggled for greater reuse and flexibility in their software.

General Categories Creational patterns – Create objects for your rather than using new Factory Method, Abstract Factory, Builder, Prototype, Singleton Structural patterns – Compose groups of objects into larger structures Adapter, Bridge, Composite, Decorator, Façade, Flyweight, Proxy Behavioral patterns – Define the communication between objects Chain of responsibility, Observer, Strategy, Command, Interpreter, Iterator

Nonfunctional Requirements may suggest a design pattern “manufacturer independent”, “device independent”, “must support a family of products” – Abstract Factory Pattern “must interface with an existing object” – Adapter Pattern “must deal with the interface to several systems, some of them to be developed in the future” – Bridge Pattern

Design Patterns Quick Reference