Mastering Python Design Patterns - Second Edition

Summary

In this chapter, we covered the Command pattern. Using this design pattern, we can encapsulate an operation, such as copy/paste, as an object. This offers many benefits, as follows:

• We can execute a command whenever we want, and not necessarily at creation time
• The client code that executes a command does not need to know any details about how it is implemented
• We can group commands and execute them in a specific order

Executing a command is like ordering at a restaurant. Each customer's order is an independent command that enters many stages and is finally executed by the cook.

Many GUI frameworks, including PyQt, use the Command pattern to model actions that can be triggered by one or more events and can be customized. However, ...