# What is Decorator Design Pattern 
Decorator pattern allows a user to add new functionality to an existing object without altering its structure.This pattern creates a decorator class which wraps the original class and provides additional functionality keeping the class methods signature intact.

## Diagram
![Diagram](https://github.com/premaseem/DesignPatternsJava9/blob/decorator-pattern/diagrams/Decorator%20Pattern%20class%20diagram.jpeg "Diagram")

![Diagram](https://github.com/premaseem/DesignPatternsJava9/blob/decorator-pattern/diagrams/4477491529_462d9dd985_b.jpeg "Diagram")

![Diagram](https://github.com/premaseem/DesignPatternsJava9/blob/decorator-pattern/diagrams/Decorator%20pattern%20sequence%20diagram.png "Diagram")

### When to use Decorator Design Pattern 
When you want to get rid of too many sub classes by creating separate class for each combination.

### Learn Design Patterns with Java by Aseem Jain
This repository contains working project code used in video Course by Packt Publication with title "Learn Design Patterns with Java " authored by "Aseem Jain".

### Course link: 
https://www.packtpub.com/application-development/learn-design-patterns-java-9-video

### ![ http://in.linkedin.com/in/premaseem](https://github.com/premaseem/DesignPatternsJava9/blob/master/linkedin.png "http://in.linkedin.com/in/premaseem") Profile:  http://in.linkedin.com/in/premaseem

### Authors blog on design patterns:
https://premaseem.wordpress.com/category/computers/design-patterns/

### Software Design pattern community face book page:
https://www.facebook.com/DesignPatternGuru/

### Note: 
* This code base will work on Java 9 and above versions. 
* `diagrams` folders carry UML diagrams.
* `pattern` folder has code of primary example. 
* `patternBonus` folder has code of secondary or bonus example.