Python: Journey from Novice to Expert

Chapter 11. Python Design Patterns II

In this chapter we will be introduced to several more design patterns. Once again, we'll cover the canonical examples as well as any common alternative implementations in Python. We'll be discussing:

• The adapter pattern
• The facade pattern
• Lazy initialization and the flyweight pattern
• The command pattern
• The abstract factory pattern
• The composition pattern

The adapter pattern

Unlike most of the patterns we reviewed in Chapter 8, Strings and Serialization, the adapter pattern is designed to interact with existing code. We would not design a brand new set of objects that implement the adapter pattern. Adapters are used to allow two pre-existing objects to work together, even if their interfaces are not compatible. Like ...