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Divide interface by use cases

Medium
SOLIDcsharp
What is it?​

This practice is activated when an interface contains methods that are unrelated or serve different user goals, which can be recognized by a cluttered interface with methods that don't logically belong together.

A bad smell is when interfaces contains more than 10 methods.

Why apply it?​

Dividing interfaces by use cases enhances readability, maintainability, and usability by ensuring that each interface serves a clear and specific purpose, reducing complexity and improving codebase modularity.

How to fix it?​

Refactor the interface by segmenting it into smaller, more focused interfaces, each capturing specific use cases or logical groupings of methods.

Read more:​

https://martinfowler.com/bliki/RoleInterface.html

Examples​

Example 1:​

Negative​

Incorrect implementation that violates the practice.

namespace Packmind;

public class ReadWriteRepository : IReadWriteRepository
{
    public IList<Order> Read()
    {
        return new List<Order>();
    }

    public void WriteOrder(Order order)
    {
        
    }
}

public interface IReadWriteRepository
{
    IList<Order> Read();
    void WriteOrder(Order order);
}