What is SOLID Principles?
Turkish: SOLID
SOLID is a set of five object-oriented design principles for making classes easier to understand, test, and adapt to change.
What are the SOLID Principles?
SOLID is an acronym for five object-oriented design principles that aim to make code more adaptable, readable, and testable. The principles guide decisions about class responsibilities, dependencies, and extensibility.
SOLID is not a framework or a mandatory checklist. Each principle points to a design question that helps reduce maintenance cost when used in the right context.
The Five Principles
- Single Responsibility: A class should have one main reason to change.
- Open/Closed: Code should be open to new behavior but closed to changes that break existing behavior.
- Liskov Substitution: Subclasses should be usable without violating the expectations of the parent type.
- Interface Segregation: Clients should not depend on methods they do not need.
- Dependency Inversion: High-level modules should depend on abstractions, not concrete classes.
Business Use
SOLID principles become valuable in business rules that are expected to change, such as payment calculation, shipping provider selection, report generation, or pricing by customer type. Well-separated responsibilities reduce unexpected side effects when new features are added.
At the same time, over-abstracting every small class does not automatically improve code. SOLID should be balanced with clean code and design pattern practices according to real change pressure.
Related Terms
Clean Code is a way of writing software that makes intent clear, keeps units small, and reduces the cost of future change.
Dependency InjectionDependency injection lets a class receive the dependencies it needs from the outside instead of constructing them itself.
Design PatternA design pattern describes a proven approach to recurring software design problems, independent of a specific language or framework.