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

Loose coupling and the Observer pattern


Loose coupling is an important design principle that should be used in software applications. The main purpose of loose coupling is to strive for loosely-coupled designs between objects that interact with each other. Coupling refers to the degree of knowledge that one object has about the other object that it interacts with.

Loosely-coupled designs allow us to build flexible object-oriented systems that can handle changes because they reduce the dependency between multiple objects.

The loose coupling architecture ensures following features:

  • It reduces the risk that a change made within one element might create an unanticipated impact on the other elements

  • It simplifies testing, maintenance, and troubleshooting problems

  • The system can be easily broken down into definable elements

The Observer pattern provides you with an object design where the Subject and Observer are loosely coupled. The following points will explain this better:

  • The only thing that the...