Java Buzz Forum - Decorator Design Pattern in Java

Decorator Pattern is one of the famous Gang of Four (GOF) structural design pattern, which provides an alternative way of extending an object's functionality. It's different than traditional way of adding new functionality into object using Inheritance, since it's based on Composition and provides additional functionality at runtime, as opposite to Inheritance, which adds new functionalities at compile time. Decorator design pattern is introduced by famous Gang of Four design pattern book, almost 2 decades ago. It's a time tested way of adding new functionalities into object. In this Java design pattern tutorial, we will learn Decorator design pattern by using it in a Java example. This is a best way of learning design pattern, followed you try it yourself to apply in similar scenarios. Decorator pattern is one of the popular design pattern along with Factory method pattern and Singleton Pattern, and you can see it's usage even in JDK itself. Couple of classes from java.io package e.g. BufferedInputStream, LineNumberInputStream are good example of Decorator design pattern in Java.


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