Design Patterns Explained: A New Perspective on Object-Oriented Design, Second Edition

Chapter 18. The Observer Pattern

Overview

In this chapter

This chapter continues the international e-commerce case study started in Chapter 9, “The Strategy Pattern,” and continued in Chapter 16, “The Analysis Matrix.”

This chapter

•   Introduces the categorization scheme of patterns.

•   Introduces the Observer pattern by discussing additional requirements for the case study.

•   Applies the Observer pattern to the case study.

•   Describes the Observer pattern.

•   Describes the key features of the Observer pattern.

•   Describes some of my experiences using the Observer pattern in practice.

Categories of Patterns

The GoF has three categories

There are many patterns to keep track of. To help sort this out, the Gang of Four ...