In Object-Oriented Programming, SOLID is an acronym for five important design principles intended to make software designs more reusable, scalable, and robust. Promoted as a subset of a set of principles by Robert C Martin, the SOLID principles are important for the creation of robust software that has low coupling, high cohesion, and strong encapsulation.
S.O.L.I.D stands for:
S – Single-Responsibility Principle
O – Open-Closed Principle
L – Liskov Substitution Principle
I – Interface Segregation Principle
D – Dependency Inversion Principle
Single-Responsibility Principle (SRP)
As per the SRP, a class must have only one responsibility and should do only the task for which it has been designed.
Benefits of using SRP: Reduced coupling and understandable code
Open-Closed Principle (OCP)
As per the OCP, software entities such as classes, functions, modules, etc, should be written in such a way that it must be easily extensible with new features without changing its existing code in use.
Benefits of using OCP: Codebase that is robust and reusable
Liskov Substitution Principle (LSP)
LSP was defined by Barbara Liskov and says that objects in a program must be replaceable by instances of their subtypes without altering the correct functioning of that program.
Benefits of using LSP: Class hierarchies are easier to understand
Interface Segregation Principle (ISP)
As per LSP, a class should not force any client to implement an interface that is irrelevant to them. It is the first principle that is applicable to Interfaces instead of classes.
Benefits of using ISP: Decoupled system and easy refactoring of code
Dependency Inversion Principle (DIP)
As per DIP, a particular class should not depend directly on another class, but rather on an abstraction of this class.
Benefits of using DIP: Reduced coupling
SOLID principles are applicable for all object-oriented programming languages such as Java, C#, Python, etc.