SOLID Principles
Study SOLID Principles
SRP, OCP, LSP, ISP, DIP with practical examples
Topics
S Single Responsibility Principle SRP
The Single Responsibility Principle says a class should have exactly one reason to change. Keeping responsibilities like validation, execution, and logging in separate classes shrinks the blast radius of every edit, makes tests…
O Open Closed Principle OCP
The Open/Closed Principle says modules should be open for extension but closed for modification: new behaviour should arrive as new types (strategies, plugins, decorators) rather than edits to battle-tested code. Done well it eliminates…
L Liskov Substitution Principle LSP
The Liskov Substitution Principle states that any subclass must be usable wherever its base type is expected, without surprises. When derived types throw NotSupportedException, strengthen preconditions, or weaken postconditions, callers…
I Interface Segregation Principle ISP
The Interface Segregation Principle says clients should never be forced to depend on methods they don't use. Splitting a fat contract into focused, role-based interfaces keeps implementations honest, shrinks the surface that mocks and…
D Dependency Inversion Principle DIP
The Dependency Inversion Principle flips the normal flow: high-level policy and low-level details both depend on abstractions, not the other way round. Injecting interfaces through constructors (wired at the composition root) decouples…