Software Design Principle: SOLID

Single Responsibility Principle

• What: A class should only have one job.

• Why:

  • If more than one then it would be coupled.

  • Easier to maintain and write the test

Open Closed Principle

• What: A class should be open for extension but closed for modification.

• Why: More extensible and guarantees that modified without changing the existing behavior.

Liskov Substitution Principle

• What:

  • The object should be replaceable by its subclass without causing any error.

  • The object of the subclass should be the subset of its parent class.

• Why: The hierarchy rules let our code easy to maintain and extend.

Interface Segregation Principle

• What: A client should not be forced to depend on methods it does not use.

Dependency Inversion Principle

• What: The module should depend on the abstraction rather than the concrete class. The abstraction should not depend on the details or entities.

• Why: Easier to make the change without affecting the existing code and easier to perform mock testing.