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. A Builder pattern is usually a better candidate than a Factory pattern when:
- We want to create a complex object (an object composed of many parts and created in different steps that might need to follow a specific order).
- Different representations of an object are required, and we want to keep the construction of an object decoupled from its representation
- 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 a Builder pattern and a Factory pattern, and gave...
