Summary
In this chapter, we learned how to use the factory method and the abstract factory design patterns. Both patterns are used when we want to track object creation, decouple object creation from object usage, or even improve the performance and resource usage of an application. Improving performance was not demonstrated in this chapter. You may consider trying it as a good exercise.
The factory method design pattern is implemented as a single function that doesn't belong to any class and is responsible for creating a single kind of object (a shape, a connection point, and so on). We saw how the factory method relates to toy construction, mentioned how it is used by Django to create different form fields, and discussed other possible use cases for it. As an example, we implemented a factory method that provided access to XML and JSON files.
The abstract factory design pattern is implemented as several factory methods that belong to a single class and are used to create...
