# What is Visitor Design Pattern 
Visitor design pattern uses a visitor class which changes the executing algorithm of an element class. By this way, execution algorithm of element can vary as and when visitor varies.

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

![Diagram](https://github.com/premaseem/DesignPatternsJava9/blob/visitor-pattern/diagrams/visitorPattern-generic.jpeg "Diagram")

![Diagram](https://github.com/premaseem/DesignPatternsJava9/blob/visitor-pattern/diagrams/VisitorSequenceDiagram.png "Diagram")

### When to use Visitor  Design Pattern 
Visitor pattern is used when we have to perform an operation on a group of similar kind of Objects. With the help of visitor pattern, we can move the operational logic from the objects(Elements) to another class (Visitor class).

### 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.