// enumerations/Shapes.java

// (c)2021 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

// {NewFeature} Preview in JDK 17

// Compile with javac flags:

// --enable-preview --source 17

// Run with java flag: --enable-preview

import java.util.*;

sealed interface Shape {

double area();

}

record Circle(double radius) implements Shape {

@Override public double area() {

return Math.PI * radius * radius;

}

}

record Rectangle(double side1, double side2)

implements Shape {

@Override public double area() {

return side1 * side2;

}

}

public class Shapes {

static void classify(Shape s) {

System.out.println(switch(s) {

case Circle c && c.area() < 100.0

-> "Small Circle: " + c;

case Circle c -> "Large Circle: " + c;

case Rectangle r && r.side1() == r.side2()

-> "Square: " + r;

case Rectangle r -> "Rectangle: " + r;

});

}

public static void main(String[] args) {

List.of(

new Circle(5.0),

new Circle(25.0),

new Rectangle(12.0, 12.0),

new Rectangle(12.0, 15.0)

).forEach(t -> classify(t));

}

}

/* Output:

Small Circle: Circle[radius=5.0]

Large Circle: Circle[radius=25.0]

Square: Rectangle[side1=12.0, side2=12.0]

Rectangle: Rectangle[side1=12.0, side2=15.0]

*/