What is Observer Design Pattern

The observer pattern is a Behavioral design pattern in which an object, called the subject, maintains a list of its dependents, called observers, and notifies them automatically of any state changes or updates.

Diagram

When to use Observer Design Pattern

• Heavy used in "event driven" application
• It is suitable for any scenario that requires push-based notification.

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

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.