S like Single responsibility principle

Single responsibility principle

Every class should have only one reason to change.

Every class should have:

• Only one goal of existence.
• Only one responsibility.
• Only one task to do.
• Only one reason for the modification.

This rule can be applied to methods, functions, classes, modules and packages.

 

Advantages

• More readable code.
• More understandable code.
• Lack of god-classes — classes, which do everything (or too much) and change with every change in the application.
• Easier software modification and maintenance.
• A small software change only affects one class.
• The modification only affects the area you want to change. A changer does not touch other areas.
• Less error-prone.

Disadvantages

• Many classes.

Examples

1. E-mail address validator in a separate class (not with user data).
2. Phone number validator in a separate class (not with user data).
3. Database writer in a separate class (not with saving data).
4. Class with address a separate class (not with client data).

All posts from mini project: Learn SOLID and OOP principles:

• SOLID
• SOLID exercises
• S like Single responsibility principle
• SOLID exercises — Kata
• O as Open-closed principle
• L jak Liskov Substitution Principle
• Interface segregation principle
• KISS — Keep it simple, stupid
• DRY — Don’t repeat yourself
• Dependency inversion principle
• SLAP — Single Level of Abstraction Principle
• Composition Over Inheritance
• Encapsulate what changes
• Lod — Law of Demeter
• ES as Exercises of Single responsibility principle
• EO as Exercises of Open/closed principle
• EL as Exercises of Liskov Substitution Principle
• EI as Eexrcises of Interface segregation principle
• ES as Exercises of Dependency Inversion Principle
• Object-oriented programming
• OOP — Object-Oriented Programming — Advice
• OOP — Object Oriented Programming

Sources

Main image

• https://www.pexels.com/photo/black-and-white-chess-chess-piece-figurine-411195/

Materials

• • Clean Architecture — Robert C. Martin
  • https://sii.pl/blog/solid-dobre-praktyki-programowania/
  • https://javadeveloper.pl/solid/
  • https://www.p-programowanie.pl/paradygmaty-programowania/zasady-solid/
  • https://www.samouczekprogramisty.pl/solid-czyli-dobre-praktyki-w-programowaniu-obiektowym/

• https://pl.wikipedia.org/wiki/Zasada_jednej_odpowiedzialno%C5%9Bci
• https://en.wikipedia.org/wiki/Single_responsibility_principle
• SRP: The Single Responsibility Principle – Robert C. Martin – https://drive.google.com/file/d/0ByOwmqah_nuGNHEtcU5OekdDMkk/view