We will take up an example of the stock exchange (much talked about in the Internet world) to demonstrate the implementation of the Command pattern. What happens in a stock exchange? You, as a user of the stock exchange, create orders to buy or sell stocks. Typically, you don't buy or sell them; it's the agent or broker who plays the intermediary between you and the stock exchange. The agent is responsible for taking your request to the stock exchange and getting the work done. Imagine that you want to sell a stock on Monday morning when the exchange opens up. You can still make the request to sell stock on Sunday night to your agent even though the exchange is not yet open. The agent then queues this request to be executed on Monday morning when the exchange is open for the trading. This presents a classical case for the Command pattern.
Learning Python Design Patterns - Second Edition - Second Edition
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Learning Python Design Patterns - Second Edition - Second Edition
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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.
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Learning Python Design Patterns - Second Edition - Second Edition
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Table of Contents (19 chapters)
Learning Python Design Patterns Second Edition
Credits
Foreword
About the Author
About the Reviewer
www.PacktPub.com
Preface
Free Chapter
Introduction to Design Patterns
The Singleton Design Pattern
The Factory Pattern – Building Factories to Create Objects
The Façade Pattern – Being Adaptive with Façade
The Proxy Pattern – Controlling Object Access
The Observer Pattern – Keeping Objects in the Know
The Command Pattern – Encapsulating Invocation
The Template Method Pattern – Encapsulating Algorithm
Model-View-Controller – Compound Patterns
The State Design Pattern
AntiPatterns
Index
Customer Reviews