Model View Controller - hvordan styres en button i controlleren?

her er alle klasserne, som de ser ud nu, men jeg mangler at få Square knappen til at fungere, så det er den der laver udregningen og ikke ved enter i numberField. hvordan ændrer jeg det?

/******************************************************************
* View
******************************************************************/
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class View extends JFrame
{
    private Model model;   
    private JTextField numberField, squareField;
    private JLabel numberLabel, squareLabel;
    private JButton button;

    public View(Model model)
    {
        this.model = model;
        Container contentPane = this.getContentPane();
        JPanel panel = new JPanel();
        numberLabel = new JLabel("Number:");
        numberField = new JTextField(5);
        squareLabel = new JLabel("m2:");
        squareField = new JTextField(5);
        squareField.setEditable(false);
        button = new JButton("Square");
        panel.add(numberLabel);
        panel.add(numberField);
        panel.add(squareLabel);
        panel.add(squareField);
        panel.add(button);
        contentPane.add(panel);
        numberField.addActionListener(new Controller(model, this));
        squareField.addActionListener(new Controller(model, this));
        button.addActionListener(new Controller(model, this));       
    }

    public int getNumber()
    {
        return Integer.parseInt(numberField.getText());
    }

    public void update()
    {
        numberField.setText("");
        squareField.setText(Integer.toString(model.getSquare()));
    }
}

/******************************************************************
* Model
******************************************************************/
public class Model
{
    private int number;

    int getNumber()
    {
        return number;
    }
   
    int getSquare()
    {
        return number * number;
    }
   
    void setNumber(int number)
    {
        this.number = number;
    }
}

/******************************************************************
* Controller
******************************************************************/
import java.awt.event.*;
import java.awt.event.*;

public class Controller implements ActionListener
{
    private Model model;
    private View view;

    public Controller(Model model, View view)
    {
        this.model = model;
        this.view = view;
    }
   
    public void actionPerformed(ActionEvent e)
    {
        model.setNumber(view.getNumber());
        view.update();
    }
}

/******************************************************************
* Test
******************************************************************/
import java.awt.event.*;

public class Test
{
    public static void main(String args[])
    {
        Model model = new Model();
        View view = new View(model);
        view.setTitle("Hello world");
        view.setSize(140, 150);
        view.setVisible(true);
        view.setResizable(false);
        view.addWindowListener(new WindowAdapter()
            {public void windowClosing(WindowEvent e) {System.exit(0);} });   
    }