Principle Classes that depend on other classes should depend on abstractions rather than concrete implementations. This makes the classes much more flexible to changing implementations. Scenario To demonstrate ISP I will continue using the E-Commerce example from the previous blog. A customer has an order which includes multiple order items. Given an order we calculate … More SOLID Principles – Part 06 – Dependency Inversion Principle

Principle Functionality should be broken into specific interfaces rather than one all-purpose interface. This means clients are not be forced to depend upon methods that they do not use. Scenario To demonstrate ISP I will continue using the E-Commerce example from the previous blog. A customer has an order which includes multiple order items. Given … More SOLID Principles – Part 05 – Interface Segregation Principle

Principle This principle is an extension of the Open Close Principle and was first introduced by Barbara Liskov during a conference keynote speech. We need to ensure that new derived classes are extending the base classes without changing their behaviour. You should be able to replace a class with its base type without altering the … More SOLID Principles – Part 04 – Liskov Substitution Principle

Principle A class should only have a single responsibility. E.g. If it’s a logging class it should only do logging. If it’s a payments class it should only do payments, and so forth. A class should only have one reason to change. Scenario To demonstrate SRP I will use an E-Commerce example. A customer has … More SOLID Principles – Part 02 – Single Responsibility Principle

It was nearly 10 years ago I picked up a book called Agile Principles, Patterns and Practises in C# by Robert C. Martin which revolutionised the way I thought about Object Orientated Programming. In this book he discussed SOLID Principles. In this blog series I will discuss each principle with code examples. This will prevent … More SOLID Principles – Part 01 – Overview