Summary

In this chapter, we have seen how to use the builder design pattern. We use the builder pattern for creating an object in situations where using the factory pattern (either a factory method or an abstract factory) is not a good option. The builder pattern is usually a better candidate than the factory pattern when we want to create a complex object, when different representations of an object are required, or when we want to create an object at one point in time but access it at a later point.

We saw how the builder pattern is used in fast-food restaurants for preparing meals, and how two third-party Django packages, django-widgy and django-query-builder, use it for generating HTML pages and dynamic SQL queries, respectively. We focused on the differences between the builder pattern and the factory pattern and provided a preconfigured (factory) and customer (builder) computer order analogy to clarify them. We also looked at how to create a pizza-ordering application with...