Writing SOLID code

SOLID is an acronym introduced by Michael Feathers summarizing the words of Robert C. Martin. The intent of SOLID is to provide developers with a set of principles that will guide them toward more maintainable code that resists becoming technical debt.

The five principles of SOLID code are:

• Single Responsibility Principle (SRP)
• Open-Closed Principle (OCP)
• Liskov Substitution Principle (LSP)
• Interface Segregation Principle (ISP)
• Dependency Inversion Principle (DIP)

In this section, we’ll cover all five of these principles.

Single Responsibility Principle

The Single Responsibility Principle (SRP) says that a class should be responsible for one thing and one thing only. Here are a few examples of classes that follow the SRP:

• A class responsible for saving application data to a specific file format
• A database access class dedicated to executing queries against a database table or set of tables
• An API controller...