programming-principles-solid.md

Programming principles (SOLID)

SOLID Principles

Single Responsibility Principle

• Do one thing and do it well.
• Short and focused methods, small and focused classes.

Open Closed Principle

• Be open for extension and closed for modification.

Liskov Substitution Principle

• Derived classes can stand in for base classes.
• Replacing an object with an instance of a subtype shouldn't alter the correctness of a program.

Interface Segregation Principle

• Make interfaces fine grained and client specific.
• Expose only those things that you absolutely have to.
• Many client-specific interfaces are better than one general-purpose interface.

Dependency Inversion

• Depend on abstractions, not concrete implementations.

Other Principles

Don't Repeat Yourself (DRY)

• Clipboard inheritance is an anti-pattern.

The Boy Scout Principle

• Clean up after yourself, clean up after others.
• For instance, add some unit tests if there are none.

You Ain't Gonna Need It (YAGNI)

• Focus on current actual requirements.

Separation Of Concerns

• Focusing one's attention upon some aspect.
• For instance, don't mix your UI and your database logic all together.
• (Similar to Single Responsibility Principle).