Описать класс, представляющий треугольник

public class Triangle {
    private Point a;
    private Point b;
    private Point c;
 
    Triangle(Point a, Point b, Point c) {
        checkPointsTriangle(a, b, c);
        this.a = a;
        this.b = b;
        this.c = c;
    }
 
    private void checkPointsTriangle(Point a, Point b, Point c) {
        if (a == null || b == null || c == null) {
            throw new IncorrectTriangleException("Point not may be null.");
        }
        double sideA = a.distanceTo(b);
        double sideB = b.distanceTo(c);
        double sideC = a.distanceTo(c);
        if (sideA * sideB * sideC == 0 || sideA + sideB <= sideC || sideA + sideC <= sideB) {
            throw new IncorrectTriangleException("incorrect triangle points.");
        }
    }
 
    public double getSideAB() {
        return this.a.distanceTo(this.b);
    }
 
    public double getSideBC() {
        return this.b.distanceTo(this.c);
    }
 
    public double getSideAC() {
        return this.a.distanceTo(this.c);
    }
 
    public double getPerimeter() {
        return getSideAB() + getSideBC() + getSideAC();
    }
 
    public double getArea() {
        double p = getPerimeter() / 2.;
        return Math.sqrt(p * (p - getSideAB()) * (p - getSideBC()) * (p - getSideAC()));
    }
 
    public void shiftTriangle(double xStep, double yStep) {
        this.a = new Point(this.a.getX() + xStep, this.a.getY() + yStep);
        this.b = new Point(this.b.getX() + xStep, this.b.getY() + yStep);
        this.c = new Point(this.c.getX() + xStep, this.c.getY() + yStep);
    }
 
    public Point getCenter() {
        double a = getSideBC();
        double b = getSideAC();
        double c = getSideAB();
        double x0 = (a * this.a.getX() + b * this.b.getX() + c * this.c.getX()) / (a + b + c);
        double y0 = (a * this.a.getY() + b * this.b.getY() + c * this.c.getY()) / (a + b + c);
        return new Point(x0, y0);
    }
 
    public void turnTriangle(int degree) {
        Point e = getCenter();
        double f = degree * (Math.PI / 180.);
        this.a = turnPoint(this.a, e, f);
        this.b = turnPoint(this.b, e, f);
        this.c = turnPoint(this.c, e, f);
    }
 
    public void changeScale(double k) {
        this.a = getScaleToPoint(this.a, k);
        this.b = getScaleToPoint(this.b, k);
        this.c = getScaleToPoint(this.c, k);
    }
 
    private Point getScaleToPoint(Point point, double k) {
        double x0 = point.getX() * k;
        double y0 = point.getY() * k;
        return new Point(x0, y0);
    }
 
    private Point turnPoint(Point point, Point e, double f) {
        Point res = new Point(point.getX() - e.getX(), point.getY() - e.getY());
        double x0 = res.getX() * Math.cos(f) - res.getY() * Math.sin(f);
        double y0 = res.getX() * Math.sin(f) + res.getY() * Math.cos(f);
        return new Point(x0 + e.getX(), y0 + e.getY());
    }
 
    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("Points:\n").append("   ");
        sb.append("A").append(this.a).append("; ");
        sb.append("B").append(this.b).append("; ");
        sb.append("C").append(this.c).append(";\n\n");
 
        sb.append("Sides [length]:\n");
        String parse = String.format("%.2f", getSideAB());
        sb.append("   ").append("AB = ").append(parse).append(";\n");
        parse = String.format("%.2f", getSideBC());
        sb.append("   ").append("BC = ").append(parse).append(";\n");
        parse = String.format("%.2f", getSideAC());
        sb.append("   ").append("AC = ").append(parse).append(";\n\n");
 
        parse = String.format("%.2f", getPerimeter());
        sb.append("Perimeter: ").append(parse).append(";\n");
        parse = String.format("%.2f", getArea());
        sb.append("Area:      ").append(parse).append(";\n\n");
 
        sb.append("Point center: O").append(getCenter()).append(";\n");
        return sb.toString();
    }
}
 
class IncorrectTriangleException extends RuntimeException {
    IncorrectTriangleException(String message) {
        super(message);
    }
}
 
class Point {
    private final double x;
    private final double y;
 
    public double getX() {
        return x;
    }
 
    public double getY() {
        return y;
    }
 
    Point(double x, double y) {
        this.x = x;
        this.y = y;
    }
 
    public double distanceTo(Point point) {
        double temp = Math.pow(point.getX() - x, 2);
        temp += Math.pow(point.getY() - y, 2);
        return Math.sqrt(temp);
    }
 
    @Override
    public String toString() {
        return String.format("(%.2f; %.2f)", this.x, this.y);
    }
}
 
class TriangleTest {
    public static void main(String[] args) {
        Triangle triangle = new Triangle(new Point(1., 1.), new Point(2., 2.), new Point(3., 0.));
        System.out.println("Triangle info:\n" + triangle);
 
        System.out.println("Shift triangle to 2.0.\n");
        triangle.shiftTriangle(2.0, 2.0);
        System.out.println("Shift triangle:\n" + triangle);
 
        System.out.println("Turn triangle to 70 degree.\n");
        triangle.turnTriangle(70);
        System.out.println("Turn triangle:\n" + triangle);
 
        System.out.println("Scale triangle to 2.0.\n");
        triangle.changeScale(2.0);
        System.out.println("Scale triangle:\n" + triangle);
    }
}

Triangle info:
Points:
   A(1,00; 1,00); B(2,00; 2,00); C(3,00; 0,00);
 
Sides [length]:
   AB = 1,41;
   BC = 2,24;
   AC = 2,24;
 
Perimeter: 5,89;
Area:      1,50;
 
Point center: O(1,86; 1,14);
 
Shift triangle to 2.0.
 
Shift triangle:
Points:
   A(3,00; 3,00); B(4,00; 4,00); C(5,00; 2,00);
 
Sides [length]:
   AB = 1,41;
   BC = 2,24;
   AC = 2,24;
 
Perimeter: 5,89;
Area:      1,50;
 
Point center: O(3,86; 3,14);
 
Turn triangle to 70 degree.
 
Turn triangle:
Points:
   A(3,70; 2,28); B(3,10; 3,57); C(5,32; 3,82);
 
Sides [length]:
   AB = 1,41;
   BC = 2,24;
   AC = 2,24;
 
Perimeter: 5,89;
Area:      1,50;
 
Point center: O(3,86; 3,14);
 
Scale triangle to 2.0.
 
Scale triangle:
Points:
   A(7,39; 4,57); B(6,20; 7,13); C(10,64; 7,64);
 
Sides [length]:
   AB = 2,83;
   BC = 4,47;
   AC = 4,47;
 
Perimeter: 11,77;
Area:      6,00;
 
Point center: O(7,72; 6,28);
 
 
Process finished with exit code 0