帮我根据以下要求：Then modify the View superclass to:  hide the frame when the user clicks on the “close” button;  add a “window closing” event handler (use an anonymous window adapter) that calls the controller’s shutdown method.修改下述代码：import javax.swing.JFrame; public abstract class View<T extends Controller> extends JFrame implements ModelListener { protected Model m; protected T c; public View(Model m, T c) { this.m = m; this.c = c; m.addListener(this); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } @Override public abstract void update(); }，public class MyFrame extends View<ControllerClicks> { public MyFrame(Model m, ControllerClicks c) { super(m, c); this.setTitle("MyFrame Title"); this.setSize(400, 300); this.setLocationRelativeTo(null); this.setLayout(new BorderLayout()); MyPanel centerPanel = new MyPanel(m, c); this.add(centerPanel, BorderLayout.CENTER); JPanel topPanel = new JPanel(); this.add(topPanel, BorderLayout.PAGE_START); topPanel.setLayout(new FlowLayout(FlowLayout.CENTER)); JButton resetButton = new JButton("Reset"); resetButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { c.resetClicked(); } }); topPanel.add(resetButton); JButton undoButton = new JButton("Undo"); undoButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { c.undoClicked(); } }); topPanel.add(undoButton); this.setVisible(true); } @Override public void update() { repaint(); // Makes Swing call MyPanel's paintComponent method. } } import javax.swing.JLabel; public class ViewNumber extends View<Controller> { private JLabel label; public ViewNumber(Model m, Controller c) { super(m, c); this.setTitle("View Number"); this.setSize(150, 150); label = new JLabel(); update(); // Initialize the label using the model. this.add(label); this.setVisible(true); } @Override public void update() { label.setText("Number of points is: " + m.numberOfPoints()); } }

修改后的代码如下：

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public abstract class View<T extends Controller> extends JFrame implements ModelListener {
protected Model m;
protected T c;

public View(Model m, T c) {
this.m = m;
this.c = c;
m.addListener(this);
this.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
c.shutdown();
}
});
}

@Override
public abstract void update();
}

public class MyFrame extends View<ControllerClicks> {
public MyFrame(Model m, ControllerClicks c) {
super(m, c);
this.setTitle("MyFrame Title");
this.setSize(400, 300);
this.setLocationRelativeTo(null);
this.setLayout(new BorderLayout());
MyPanel centerPanel = new MyPanel(m, c);
this.add(centerPanel, BorderLayout.CENTER);
JPanel topPanel = new JPanel();
this.add(topPanel, BorderLayout.PAGE_START);
topPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
JButton resetButton = new JButton("Reset");
resetButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
c.resetClicked();
}
});
topPanel.add(resetButton);
JButton undoButton = new JButton("Undo");
undoButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
c.undoClicked();
}
});
topPanel.add(undoButton);
this.setVisible(true);
}

@Override
public void update() {
repaint(); // Makes Swing call MyPanel's paintComponent method.
}
}

import javax.swing.JLabel;

public class ViewNumber extends View<Controller> {
private JLabel label;

public ViewNumber(Model m, Controller c) {
super(m, c);
this.setTitle("View Number");
this.setSize(150, 150);
label = new JLabel();
update(); // Initialize the label using the model.
this.add(label);
this.setVisible(true);
}

@Override
public void update() {
label.setText("Number of points is: " + m.numberOfPoints());
}
}