Exercise – Design patterns

There are many OOD patterns that have shared software-design solutions of specific coding problems. OOD patterns are also often used by programmers as the way to talk about different implementations. 

They are traditionally grouped into four categories: creational, behavioral, structural, and concurrency patterns. Read about them and:

• Name one pattern in each category
• Name three patterns we have used already

Answer

The four patterns—one from each of the four categories—could be the following:

• Creational patterns: Factory method
• Structural patterns: Composite
• Behavioral patterns: Visitor
• Concurrency patterns: Messaging pattern

In this book, we have already used the following patterns:

• Lazy initialization: In Chapter 6, Interfaces, Classes, and Object Construction, we initialized the SingletonClassExample OBJECT static field, not automatically, but only when the getInstance() method was called
• Singleton: In Chapter 6, Interfaces, Classes, and Object Construction, see the SingletonClassExample...