我想通过重置按钮重置网格

public class ButtonGrid extends JFrame{


private final JButton[][] grid;
private int length,width;

public ButtonGrid(int width,int length){

    JPanel panel = new JPanel();
    JButton start = new JButton("Start");
    JButton reset = new JButton("Reset");
    panel.add(start);
    //start.addActionListener(this);
    panel.add(reset);

    add(panel,BorderLayout.PAGE_START);
    JPanel panel1 = new JPanel();
    panel1.setLayout(new GridLayout(width,length));
    grid = new JButton[width][length];

    for(int y=0; y<length; y++){
        for(int x=0; x<width; x++){
            grid[x][y]=new JButton();
            grid[x][y].setBackground(Color.WHITE);
            panel1.add(grid[x][y]);
            grid[x][y].addActionListener(new ActionListener(){
                public void actionPerformed(ActionEvent e){
                    Object source = e.getSource();
                    JButton b1 = (JButton)source;
                    if(b1 == source){
                    b1.setBackground(Color.BLACK);
                    }
                }
            });
            reset.addActionListener(new ActionListener(){
                public void actionPerformed(ActionEvent e){
                    Object source = e.getSource();
                    JButton b1 = (JButton)source;
                    if(b1 == source){
                    b1.setBackground(Color.WHITE);
                }
                }
            });
            }
    }


    add(panel1,BorderLayout.CENTER);
    panel1.setBackground(Color.RED);

    setSize(600,600);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
}
        public static void main(String[] args) {
     EventQueue.invokeLater(new Runnable() {
     public void run() {
     ButtonGrid bg = new ButtonGrid(25,25);
      }
     });
    }
}
public class ButtonGrid extends JFrame{


priva