Design patterns in object oriented analysis and design

Design pattern is a general reusable solution to a commonly occurring problem in software development. Good OO designs are reusable, extensible and maintainable. Patterns only give you a general rule not code. Patterns show you how to build systems with good OO design qualities. Most of them address issues of change in software and allow some part of a system to vary independently of all other parts by trying to take what varies in a system and encapsulate it. Patterns also provide a shared language that can maximize the value of your communication with other developers. In this paper, we briefly introduce the concept of software design pattern and give a research on some design patterns including Strategy Pattern, Iterator Pattern, Adapter Pattern and Façade Pattern.