Java Example

• shapes

  • shapes/Circle.java

    package refactoring_guru.prototype.example.shapes;
    
    public class Circle extends Shape {
        public int radius;
    
        public Circle() {
        }
    
        public Circle(Circle target) {
            super(target);
            if (target != null) {
                this.radius = target.radius;
            }
        }
    
        @Override
        public Shape clone() {
            return new Circle(this);
        }
    
        @Override
        public boolean equals(Object object2) {
            if (!(object2 instanceof Circle) || !super.equals(object2)) return false;
            Circle shape2 = (Circle) object2;
            return shape2.radius == radius;
        }
    }

  • shapes/Rectangle.java

    package refactoring_guru.prototype.example.shapes;
    
    public class Rectangle extends Shape {
        public int width;
        public int height;
    
        public Rectangle() {
        }
    
        public Rectangle(Rectangle target) {
            super(target);
            if (target != null) {
                this.width = target.width;
                this.height = target.height;
            }
        }
    
        @Override
        public Shape clone() {
            return new Rectangle(this);
        }
    
        @Override
        public boolean equals(Object object2) {
            if (!(object2 instanceof Rectangle) || !super.equals(object2)) return false;
            Rectangle shape2 = (Rectangle) object2;
            return shape2.width == width && shape2.height == height;
        }
    }

  • shapes/Shape.java

    package refactoring_guru.prototype.example.shapes;
    
    import java.util.Objects;
    
    public abstract class Shape {
        public int x;
        public int y;
        public String color;
    
        public Shape() {
        }
    
        public Shape(Shape target) {
            if (target != null) {
                this.x = target.x;
                this.y = target.y;
                this.color = target.color;
            }
        }
    
        public abstract Shape clone();
    
        @Override
        public boolean equals(Object object2) {
            if (!(object2 instanceof Shape)) return false;
            Shape shape2 = (Shape) object2;
            return shape2.x == x && shape2.y == y && Objects.equals(shape2.color, color);
        }
    }

• Demo.java

package refactoring_guru.prototype.example;

import refactoring_guru.prototype.example.shapes.Circle;
import refactoring_guru.prototype.example.shapes.Rectangle;
import refactoring_guru.prototype.example.shapes.Shape;

import java.util.ArrayList;
import java.util.List;

public class Demo {
    public static void main(String[] args) {
        List<Shape> shapes = new ArrayList<>();
        List<Shape> shapesCopy = new ArrayList<>();

        Circle circle = new Circle();
        circle.x = 10;
        circle.y = 20;
        circle.radius = 15;
        circle.color = "red";
        shapes.add(circle);

        Circle anotherCircle = (Circle) circle.clone();
        shapes.add(anotherCircle);

        Rectangle rectangle = new Rectangle();
        rectangle.width = 10;
        rectangle.height = 20;
        rectangle.color = "blue";
        shapes.add(rectangle);

        cloneAndCompare(shapes, shapesCopy);
    }

    private static void cloneAndCompare(List<Shape> shapes, List<Shape> shapesCopy) {
        for (Shape shape : shapes) {
            shapesCopy.add(shape.clone());
        }

        for (int i = 0; i < shapes.size(); i++) {
            if (shapes.get(i) != shapesCopy.get(i)) {
                System.out.println(i + ": Shapes are different objects (yay!)");
                if (shapes.get(i).equals(shapesCopy.get(i))) {
                    System.out.println(i + ": And they are identical (yay!)");
                } else {
                    System.out.println(i + ": But they are not identical (booo!)");
                }
            } else {
                System.out.println(i + ": Shape objects are the same (booo!)");
            }
        }
    }
}

0: Shapes are different objects (yay!)
0: And they are identical (yay!)
1: Shapes are different objects (yay!)
1: And they are identical (yay!)
2: Shapes are different objects (yay!)
2: And they are identical (yay!)