::: 책 읽는 프로그래머 :::

Motivation Sometimes it's important to have only one instance for a class. For example, in a system there should be only one window manager (or only a file system or only a print spooler). Usually singletons are used for centralized management of internal or external resources and they provide a global point of access to themselves. The singleton pattern is one of the simplest design patterns: i..

Motivation Also known as Virtual Constructor, the Factory Method is related to the idea on which libraries work: a library uses abstract classes for defining and maintaining relations between objects. One type of responsibility is creating such objects. The library knows when an object needs to be created, but not what kind of object it should create, this being specific to the application using..

Motivation Modularization is a big issue in today's programming. Programmers all over the world are trying to avoid the idea of adding code to existing classes in order to make them support encapsulating more general information. Take the case of a information manager which manages phone number. Phone numbers have a particular rule on which they get generated depending on areas and countries. If..

Motivation The Factory Design Pattern is probably the most used design pattern in modern programming languages like Java and C#. It comes in different variants and implementations. If you are searching for it, most likely, you'll find references about the GoF patterns: Factory Method and Abstract Factory. In this article we'll describe a flavor of factory pattern commonly used nowdays. You can a..

Motivation Extending an objects functionality can be done statically (at compile time) by using inheritance however it might be necessary to extend an objects functionality dynamically (at runtime) as an object is used. Consider the typical example of a graphical window. To extend the functionality of the graphical window for example by adding a frame to the window, would require extending the w..

Motivation We can not talk about Object Oriented Programming without considering the state of the objects. After all object oriented programming is about objects and their interaction. The cases when certain objects need to be informed about the changes occured in other objects are frequent. To have a good design means to decouple as much as possible and to reduce the dependencies. The Observer ..

Strategy Motivation There are common situations when classes differ only in their behavior. For this cases is a good idea to isolate the algorithms in separate classes in order to have the ability to select different algorithms at runtime. Intent Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that us..

Adapter(적응자) Adapter?— Adapter는 개조시키다 라는 의미로 직류 10볼트의 컴퓨터를 교류 100볼트로 환경에 맞게 바꿔서 사용가능하게 하는것을 말한다.— 프로그래밍에서의 Adapter은 이미 제공되는 인터페이스를 다른 클래스에서도 재사용할수 있도록 바꿔주는 디자인패턴이다.Adapter 의 의도— 클래스의 인터페이스를 사용자가 기대하는 인터페 이스 형태로 적응(변환)— 함께 동작시킴— 다른이름 : 래퍼(Wrapper) 어떠한 장치가 있을 때 다른 장치에 도움을 받아야 할 때 그 장치간에 호환성이 있어야 한다.인터페이스를 우리가 사용할 수 있는 인터페이스를 바꿔주는 장치가 아답터 이다.주된 개체가 사용할 수 있는 인터페이스에 맞게끔 다른 클래스를 이용해서 주된 개체가 사용할 수 있는 인..