SRP(Single Responsibility Principle)

SRP

SRP (Single Responsibility Principle), also known as the Single Responsibility Principle, is an object-oriented design principle stating that a class should have only one responsibility.

• A responsibility is synonymous with a role or a reason for change. If a single class changes for multiple reasons, it indicates it has more than one responsibility.
• “Only one role”

Bad example

class Report {
 
    String title;
    String content;
 
    void saveToFile() { /* Save to file */ }
    void print() { /* Print to console */ }
}

In this example, responsibilities for data management, printing, and saving are all mixed within one class.

Good example

class Report {
 
    String title;
    String content;
}
 
class ReportPrinter {
 
    void print(Report report) { ... }
}
 
class ReportSaver {
 
    void saveToFile(Report report) { ... }
}

Each class now has only one responsibility. The reasons for changes are clearly separated.

Method	Explanation
Separate into functional classes	Don’t put multiple roles into a single class
Separation of Concerns (SoC)	Clearly separate UI, logic, repository, etc.
Design for a single responsibility	Create a structure where there’s only one reason for change