Book Image

Learning Python Design Patterns - Second Edition - Second Edition

By : Chetan Giridhar, Gennadiy Zlobin
Book Image

Learning Python Design Patterns - Second Edition - Second Edition

By: Chetan Giridhar, Gennadiy Zlobin

Overview of this book

With the increasing focus on optimized software architecture and design it is important that software architects think about optimizations in object creation, code structure, and interaction between objects at the architecture or design level. This makes sure that the cost of software maintenance is low and code can be easily reused or is adaptable to change. The key to this is reusability and low maintenance in design patterns. Building on the success of the previous edition, Learning Python Design Patterns, Second Edition will help you implement real-world scenarios with Python’s latest release, Python v3.5. We start by introducing design patterns from the Python perspective. As you progress through the book, you will learn about Singleton patterns, Factory patterns, and Façade patterns in detail. After this, we’ll look at how to control object access with proxy patterns. It also covers observer patterns, command patterns, and compound patterns. By the end of the book, you will have enhanced your professional abilities in software architecture, design, and development.
Table of Contents (19 chapters)
Learning Python Design Patterns Second Edition
Credits
Foreword
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

The Observer pattern in the real world


We will take up a news agency case to demonstrate the real-world scenario for the Observer pattern. News agencies typically gather news from various locations and publish them to the subscribers. Let's look at the design considerations for this use case.

With information being sent/received in real time, a news agency should be able to publish the news as soon as possible to its subscribers. Additionally, because of the advancements in the technology industry, it's not just the newspapers, but also the subscribers that can be of different types such as an e-mail, mobile, SMS, or voice call. We should also be able to add any other type of subscriber in the future and budgeting for any new technology.

Let's develop an application in Python v3.5 and implement the preceding use case. We will start with the Subject, which is the news publisher:

  • Subject behavior is represented by the NewsPublisher class

  • NewsPublisher provides you with an interface so that subscribers...