Test-Driven Development in Java/

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Simplifying Maintenance with SRP

Simplifying Maintenance with SRP

Explore how to refactor to adhere to SRP, streamlining future maintenance and enhancing code readability.

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Refactoring for single responsibility

To see the value of applying SRP, let’s consider a piece of code that doesn’t use it. The following code snippet has a list of shapes that all get drawn when we call the draw() method:

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main.java
Rectangle.java
Textbox.java
Shape.java
Graphics.java
Shapes.java
import java.util.ArrayList;
import java.util.List;
public class main {
    public static void main(String[] args) {
        Shapes shapes = new Shapes();
        shapes.add(new TextBox("Hello, World!"));
        shapes.add(new Rectangle(5, 3));
        Graphics graphics = new Graphics();
        shapes.draw(graphics);
    }
}

We can see that this code has four responsibilities, as follows:

  • Managing the list of shapes with the add() method

  • Drawing all the shapes in the list with the draw() method

  • Knowing every type of shape in the switch statement

  • Has implementation details for drawing each shape type in the case statement

If we want ...