Advanced Python Programming - Second Edition

Chapter 26: The Observer Pattern

We use the observer pattern when we want to be able to inform/notify all stakeholders (an object or a group of objects) when the state of an object changes. An important feature of the observer pattern is that the number of subscribers/observers, as well as who the subscribers are, may vary and can be changed at runtime.

In this chapter, we will learn about this design pattern while comparing it to a similar one we have seen in the past, known as the MVC pattern, and use it to implement a data formatter.

Specifically, we will cover the following topics:

• Understanding the observer pattern
• Real-world examples
• Use cases
• Implementation

Technical requirements

The code files for this chapter can be found at https://github.com/PacktPublishing/Advanced-Python-Programming-Second-Edition/tree/main/Chapter26 ...