Professional ASP.NET Design Patterns

Chapter 5. The Business Logic Layer: Patterns

WHAT'S IN THIS CHAPTER?

• How to use the Factory, Decorator, Template, State, Strategy, and Composite GoF patterns in the business layer of an ASP.NET application

• Demonstrations of how to utilize the Specification and Layer Supertype enterprise patterns in your ASP.NET code

• Improve your code's maintainability and flexibility with Dependency Injection, Interface Segregation, and the Liskov Substitution Principle

The previous chapter introduced the kinds of patterns you can use to organize your applications' middleware. This chapter looks at some specific patterns that you can leverage within the business logic layer. You examine some Gang of Four design patterns, some Enterprise design patterns, and finally some design principles that can help you keep your business logic loosely coupled and highly cohesive. You can use design patterns in any layer of your application. The series of patterns and principles in this chapter is shown in the context of the business layer of an application, but nothing can stop you from applying these patterns in the presentation, infrastructure, or data access layers of your application.

LEVERAGING DESIGN PATTERNS

In this first section, you look at the following design patterns that can assist you in your solution to your application's business problems:

• Factory Method pattern

• Decorator pattern

• Template Method pattern

• State pattern

• Strategy pattern

Factory Method

The Factory Method pattern belongs to the creational group ...