In object-oriented programming (OOP), SOLID is an acronym that represents a set of five design principles that aim to make software designs more understandable, flexible, and maintainable. These principles were introduced by Robert C. Martin and have become widely accepted in the software development community. The SOLID principles are:
- Single Responsibility Principle (SRP):A class should have only one reason to change, meaning that it should have only one responsibility or job. This principle encourages the organization of code in a way that each class or module has a clear and distinct purpose.
- Open/Closed Principle (OCP):Software entities (classes, modules, functions, etc.) should be open for extension but closed for modification. This principle promotes the idea that new functionality should be added through the introduction of new code rather than altering existing code.
- Liskov Substitution Principle (LSP):Subtypes must be substitutable for their base types without altering the correctness of the program. In simpler terms, objects of a superclass should be replaceable with objects of a subclass without affecting the correctness of the program.
- Interface Segregation Principle (ISP):A class should not be forced to implement interfaces it does not use. This principle suggests that it is better to have several small, specific interfaces rather than a large, general-purpose one. This helps avoid classes being burdened with methods they don't need.
- Dependency Inversion Principle (DIP):High-level modules should not depend on low-level modules; both should depend on abstractions. Additionally, abstractions should not depend on details; details should depend on abstractions. This principle promotes the use of interfaces or abstract classes to decouple high-level and low-level components, allowing for more flexibility and easier maintenance.