In this chapter, we have seen 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 the performance was not demonstrated in this chapter. You might 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 the creation of 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 for creating different form fields, and discussed other possible use cases for it. As an example, we implemented a factory method that provided access to the XML and JSON files.
The abstract factory design pattern is implemented as a number of factory methods that belong to a single class and are used to create a family of related objects (the parts of a car, the environment of a game, and so forth). We mentioned how the abstract factory is related to car manufacturing, how the django_factory package for Django makes use of it to create clean tests, and then we covered its common use cases. Our implementation example of the abstract factory is a mini-game that shows how we can use many related factories in a single class.
In the next chapter, we will discuss the builder pattern, which is another creational pattern that can be used for fine-tuning the creation of complex objects.
