Implement the ADT with a Java Example

Problem:

Implement the ADT below:
ADT: Point
amplitude(): Real
distanceTo(Point): Real
equals(Point): Boolean
magnitude(): Real
toString(): String
xCoordinate(): Real
yCoordinate(): Real

Output:

Not applicable.

Solution:

public class MyPoint implements Point {
 private double x, y;
 public static Point ORIGIN = new MyPoint();
 private MyPoint() {
 }
 public MyPoint(double x, double y) {
 this.x = x;
 this.y = y;
 }
 public double amplitude() {
 return Math.atan(y/x);
 }
 public double distanceTo(Point point) {
 if (point.equals(this)) {
 return 0.0;
 } else if (!(point instanceof MyPoint)) {
 throw new IllegalArgumentException("use a MyPoint object");
 } else {
 MyPoint that = (MyPoint)point;
 double dx = that.x - this.x;
 double dy = that.y - this.y;
 return Math.sqrt(dx*dx + dy*dy);
 }
 }
 public boolean equals(Object object) {
 if (object==this) {
 return true;
 } else if (!(object instanceof MyPoint)) {
 return false;
 }
 MyPoint that = (MyPoint)object;
 return (that.x == this.x && that.y == this.y); 
 }
 public double magnitude() {
 return Math.sqrt(x*x + y*y);
 }
public String toString() {
 return String.format("(%.2f,%.2f)", x, y);
 }
 public double xCoordinate() {
 return x;
 }
 public double yCoordinate() {
 return y;
 }
}