01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
package types.point5;
import java.awt.Color;
interface Colored {
  Color getColor();
}
interface Point {
  double getX();
  double getY();
}
interface ColoredPoint
extends Colored, Point
{ }
final class CartesianPoint implements ColoredPoint {
  
  private final double x;
  private final double y;
  private final Color color;
  public CartesianPoint(double x, double y, Color color) {
    this.x = x;
    this.y = y;
    this.color = color;
  }
  public double getX() { return x; }
  public double getY() { return y; }
  public Color getColor() {
    System.out.println("It's Cartesian!");
    return color;
  }
  
}
final class PolarPoint implements ColoredPoint {
  
  private final double theta;
  private final double r;
  private final Color color;
  public PolarPoint(double theta, double r, Color color) {
    this.theta = theta;
    this.r = r;
    this.color = color;
  }
  public double getX() { return r*Math.cos(theta); }
  public double getY() { return r*Math.sin(theta); }
  public Color getColor() {
    System.out.println("It's Polar!");
    return color;
  }
  
}
public class Main {
  private Main() {}
  public static void printColoredPoint(ColoredPoint cp) {
    System.out.println(cp.getX());
    System.out.println(cp.getY());
    System.out.println(cp.getColor());
  }
  public static void main(String[] args) {
    printColoredPoint(new CartesianPoint(0,0,Color.RED));
    printColoredPoint(new PolarPoint(0,0,Color.RED));
  }
}