Chapter 14. Useful Design Patterns

A design pattern is a reusable, somewhat language-specific solution to a common problem in software design. The most popular book on this topic is Design Patterns: Elements of Reusable Object-Oriented Software, Addison-Wesley Professional, written by Gamma, Helm, Johnson, and Vlissides, also known as the Gang of Four or GoF. It is considered as a major writing in this area and provides a catalogue of 23 design patterns with examples in SmallTalk and C++.

While designing an application code, these patterns help in solving common problems. They ring a bell to all developers since they describe proven development paradigms. But they should be studied with the used language in mind, since some of them do not make sense in some languages or are already built-in.

This chapter describes the most useful patterns in Python or patterns that are interesting to discuss, with implementation examples. The following are the three sections that correspond to design...