Summary

In this chapter we discussed the following:

• What design patterns are and the benefits of using design patterns to design a system.
• How patterns are categorized into creational, structural, and behavioral patterns.
• The Singleton pattern and how it compares with Java and Kotlin implementations.
• Implementing the factory pattern.
• Implementing the observer pattern.
• Implementing the decorator and handler patterns.
• Selecting appropriate patterns for the problem that we are trying to solve.