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

A UML class diagram


We will now discuss the Façade pattern with the help of the following UML diagram:

As we observe the UML diagram, you'll realize that there are three main participants in this pattern:

  • Façade: The main responsibility of a façade is to wrap up a complex group of subsystems so that it can provide a pleasing look to the outside world.

  • System: This represents a set of varied subsystems that make the whole system compound and difficult to view or work with.

  • Client: The client interacts with the Façade so that it can easily communicate with the subsystem and get the work completed. It doesn't have to bother about the complex nature of the system.

You will now learn a little more about the three main participants from the data structure's perspective.

Façade

The following points will give us a better idea of Façade:

  • It is an interface that knows which subsystems are responsible for a request

  • It delegates the client's requests to the appropriate subsystem objects using composition

For...