如何将rectangle 转换成polygon

如题，如何将rectangle 转换成polygon
源代码如何修改能将rectangle 转换成polygon运行？
import java.awt.Graphics;
import java.awt.Polygon;

import java.util.ArrayList;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class FloorLayout extends JPanel {
public static int width;
public static int height;
ArrayList toDraw;

// Constructor
public FloorLayout(int width, int height) {
    this.width=width;
    this.height=height;
    toDraw =new ArrayList<Polygon>();/
}

public void addToDraw(Polygon poly) {
    toDraw.add(poly);// to be written
}

public void addRectangle(int xPos, int yPos, int dX, int dY) {
    Polygon poly = new Rectangle(); 
    toDraw.add(poly);

}

@Override
public void paintComponent(Graphics g){
    g.drawRect(10,10,200,300);
}


public static void main(String[] toDraw) {
    FloorLayout panel =  new FloorLayout(600, 400);
    Polygon poly1 = new Rectangle(17,23,24,26);
    Polygon poly2 = new Rectangle(27,23,24,26);
    Polygon poly3 = new Rectangle(37,23,24,26);
    toDraw.add(poly1);
    toDraw.add(poly2);
    toDraw.add(ploy3);

    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    final int FRAME_WIDTH = 800;
    final int FRAME_HEIGHT = 600;
    frame.setSize(FRAME_WIDTH,FRAME_HEIGHT); 
    frame.add(panel); 
    frame.setVisible(true); 
}

}

就是把矩形的坐标连接起来就可以了。构造对象