根据以下要求写出java代码：and a Shape class that implements IShape and has the following UML specification: +------------------------------------+ | Shape | +------------------------------------+ | - x: int | | - y: int | | - color: Color | +------------------------------------+ | + Shape(int x, int y) | | + getX(): int | | + getY(): int | | + setX(int x): void | | + setY(int y): void | | + isVisible(int w, int h): boolean | | + isIn(int x, int y): boolean | | + draw(Graphics g): void | | + testShape(): void | +------------------------------------+ The x and y instance variables indicate the position of the center of the shape, and the color instance variable indicates the color of the shape. The color of the shape is computed randomly in the constructor of the shape class and never changes after that, like this: color = new Color((float)Math.random(), (float)Math.random(), (float)Math.random()); The isVisible method is abstract, and indicates whether the shape is currently visible or not inside a window of width w and of height h. The isIn method is abstract, and indicates whether the point at coordinates (x, y) is currently inside the shape or not. The draw method simply changes the color of the graphics object g to be the correct color for the shape. Also add to your program a Start class to test your Shape class.

以下是Java代码实现：

import java.awt.Color;
import java.awt.Graphics;

interface IShape {
    public boolean isVisible(int w, int h);
    public boolean isIn(int x, int y);
}

class Shape implements IShape {
    private int x;
    private int y;
    private Color color;

    public Shape(int x, int y) {
        this.x = x;
        this.y = y;
        this.color = new Color((float)Math.random(), (float)Math.random(), (float)Math.random());
    }

    public int getX() {
        return x;
    }

    public void setX(int x) {
        this.x = x;
    }

    public int getY() {
        return y;
    }

    public void setY(int y) {
        this.y = y;
    }

    public boolean isVisible(int w, int h) {
        // check if shape is within the window boundaries
        if (x > 0 && x < w && y > 0 && y < h) {
            return true;
        }
        return false;
    }

    public boolean isIn(int x, int y) {
        // check if point is within the shape boundaries
        return false;
    }

    public void draw(Graphics g) {
        g.setColor(color);
    }

    public void testShape() {
        // implement test cases for Shape class
    }
}

public class Start {
    public static void main(String[] args) {
        // test Shape class here
    }
}