SOLIDdesign

SOLIDdesign is a term used to describe a set of object-oriented design principles commonly referred to as SOLID. The acronym SOLID stands for Single Responsibility Principle, Open/Closed Principle, Liskov Substitution Principle, Interface Segregation Principle, and Dependency Inversion Principle. These principles guide the structuring of software modules to improve maintainability, extensibility, and testability. The concept originated with Robert C. Martin, who helped popularize the principles in the early 2000s, with the acronym later popularized by Michael Feathers.

The five principles are defined as follows: Single Responsibility Principle states that a module should have one reason to change; Open/Closed Principle states that software entities should be open to extension but closed to modification; Liskov Substitution Principle requires that objects of a superclass be replaceable with objects of a subclass without altering correctness; Interface Segregation Principle advocates many small, client-specific interfaces rather than a single, broad one; Dependency Inversion Principle suggests depending on abstractions rather than concrete implementations, and that high-level modules should not depend on low-level modules.

Adoption and critique: SOLIDis widely taught and applied in languages such as Java, C#, C++, and Python, particularly during design refinement and refactoring. Critics warn against over-engineering, noting that SOLID can be misapplied or less suitable in simple or performance-critical contexts, as well as in functional programming domains where different design patterns apply.

Overall, SOLIDdesign remains a foundational concept in modern software design, guiding developers toward modular, testable architectures while encouraging context-aware application.