Decorator پترن در جاوا (Design Pattern)

public interface Shape {
     void draw();
}
public class Circle implements Shape {

     @Override
     public void draw() {
          System.out.println("Shape: Circle");
     }
}
public class Rectangle implements Shape {

     @Override
     public void draw() {
          System.out.println("Shape: Rectangle");
     }
}
public abstract class ShapeDecorator implements Shape {
     protected Shape decoratedShape;

     public ShapeDecorator(Shape decoratedShape) {
          this.decoratedShape = decoratedShape;
     }

     public void draw() {
          decoratedShape.draw();
     }
}
public class RedShapeDecorator extends ShapeDecorator {

     public RedShapeDecorator(Shape decoratedShape) {
          super(decoratedShape);
     }

     @Override
     public void draw() {
          decoratedShape.draw();
          setRedBorder(decoratedShape);
     }

     private void setRedBorder(Shape decoratedShape) {
          System.out.println("Border Color: Red");
     }
}

public static void main(String[] args) {

          Shape circle = new Circle();

          Shape redCircle = new RedShapeDecorator(new Circle());

          Shape redRectangle = new RedShapeDecorator(new Rectangle());
          System.out.println("Circle with normal border");
          circle.draw();

          System.out.println("\nCircle of red border");
          redCircle.draw();

          System.out.println("\nRectangle of red border");
          redRectangle.draw();
     }