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 Abstract Factory pattern


The main objective of the Abstract Factory pattern is to provide an interface to create families of related objects without specifying the concrete class. While the factory method defers the creation of the instance to the subclasses, the goal of Abstract Factory method is to create families of related objects:

A UML Diagram for the Abstract Factory pattern

As shown in the diagram, ConcreteFactory1 and ConcreteFactory2 are created from the AbstractFactory interface. This interface has methods to create multiple products.

ConcreteFactory1 and ConcreteFactory2 implement AbstractFactory and create instances of ConcreteProduct1, ConcreteProduct2, AnotherConcreteProduct1, and AnotherConcreteProduct2.

ConcreteProduct1 and ConcreteProduct2 are in turn created from the AbstractProduct interface, and AnotherConcreteProduct1 and AnotherConcreteProduct2 are created from the AnotherAbstractProduct interface.

In effect, Abstract Factory patterns make sure that the client is...