Problems getting data from JMenuBar to JInternalFrame

Question

I have modified an example to show my problem. I am trying to take text input from the menu bar and print it into a JTextArea. I don't know how to reference the data in my ActionListener.
The ActionListener is incomplete, but this is basically what I am trying to do:
import javax.swing.JInternalFrame;
import javax.swing.JDesktopPane;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JMenuBar;
import javax.swing.JFrame;
import javax.swing.KeyStroke;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
* InternalFrameDemo.java is a 1.4 application that requires:
*   MyInternalFrame.java
public class InternalFrameDemo extends JFrame
                               implements ActionListener {
    JDesktopPane desktop;
    JTextField memAddrBox;
    JTextArea menuText;
    JTextArea frame;
    String textFieldString = " Input Text: ";
    ActionListener al;
    public InternalFrameDemo() {
        super("InternalFrameDemo");
        //Make the big window be indented 50 pixels from each edge
        //of the screen.
        int inset = 50;
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        setBounds(inset, inset,
                  screenSize.width  - inset*2,
                  screenSize.height - inset*2);
        //Set up the GUI.
        desktop = new JDesktopPane(); //a specialized layered pane
        frame = createFrame(); //create first "window"
        setContentPane(desktop);
        setJMenuBar(createMenuBar());
        //Make dragging a little faster but perhaps uglier.
        desktop.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
    protected JMenuBar createMenuBar() {
        JMenuBar menuBar = new JMenuBar();
        JLabel memAddrLabel = new JLabel(textFieldString);
        memAddrLabel.setLabelFor(memAddrBox);
        menuBar.add(memAddrLabel);
        JTextField memAddrBox = new JTextField();
        memAddrBox.addActionListener(this);
        memAddrBox.setActionCommand("chMemAddr");
        menuBar.add(memAddrBox);
        return menuBar;
    //React to menu selections.
    public void actionPerformed(ActionEvent e) {
        if ("chMemAddr".equals(e.getActionCommand())) 
            JMenuBar bar = getJMenuBar();
//            JTextField memAddrBox = bar.getParent();
            String memStartString = memAddrBox.getText();
            update(memStartString);
    public void update(String temp)
        frame.setText(temp);
    //Create a new internal frame.
    protected JTextArea createFrame() {
        JInternalFrame frame = new JInternalFrame("Memory",true,true,true,true);      
        frame.setSize(650, 500);
        frame.setVisible(true);
        frame.setLocation(200, 0);
        desktop.add(frame);  
        JTextArea textArea = new JTextArea();
        frame.getContentPane().add("Center", textArea);
        textArea.setFont(new Font("SansSerif", Font.PLAIN, 12));
        textArea.setVisible(true);
        textArea.setText("Initial Text");
        return textArea;
    //Quit the application.
    protected void quit() {
        System.exit(0);
    public static void main(String[] args) {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
        //Create and set up the window.
        InternalFrameDemo frame = new InternalFrameDemo();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Display the window.
        frame.setVisible(true);
class MyInternalFrame extends JInternalFrame {
    static int openFrameCount = 0;
    static final int xOffset = 30, yOffset = 30;
    public MyInternalFrame() {
        super("Document #" + (++openFrameCount),
              true, //resizable
              true, //closable
              true, //maximizable
              true);//iconifiable
        //...Create the GUI and put it in the window...
        //...Then set the window size or call pack...
        setSize(300,300);
        //Set the window's location.
        setLocation(xOffset*openFrameCount, yOffset*openFrameCount);
}I want to take the input from the "memAddrBox" and put it into the "frame" using the update() method. Probably a simple solution, but I have not found a similar problem in the Forums.

Answer 1

I knew it had to be something simple, here is the fix I found:
import javax.swing.JInternalFrame;
import javax.swing.JDesktopPane;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JMenuBar;
import javax.swing.JFrame;
import javax.swing.KeyStroke;
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
* InternalFrameDemo.java is a 1.4 application that requires:
*   MyInternalFrame.java
public class InternalFrameDemo extends JFrame
                               implements ActionListener {
    JDesktopPane desktop;
    JTextField memAddrBox;
    JTextArea menuText;
    JTextArea frame;
    String textFieldString = " Input Text: ";
    ActionListener al;
    public InternalFrameDemo() {
        super("InternalFrameDemo");
        //Make the big window be indented 50 pixels from each edge
        //of the screen.
        int inset = 50;
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        setBounds(inset, inset,
                  screenSize.width  - inset*2,
                  screenSize.height - inset*2);
        //Set up the GUI.
        desktop = new JDesktopPane(); //a specialized layered pane
        frame = createFrame(); //create first "window"
        setContentPane(desktop);
        setJMenuBar(createMenuBar());
        //Make dragging a little faster but perhaps uglier.
        desktop.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
    protected JMenuBar createMenuBar() {
        JMenuBar menuBar = new JMenuBar();
        JLabel memAddrLabel = new JLabel(textFieldString);
        memAddrLabel.setLabelFor(memAddrBox);
        menuBar.add(memAddrLabel);
        JTextField memAddrBox = new JTextField();
        memAddrBox.addActionListener(this);
        memAddrBox.setActionCommand("chMemAddr");
        menuBar.add(memAddrBox);
        return menuBar;
    //React to menu selections.
    public void actionPerformed(ActionEvent e) {
        if ("chMemAddr".equals(e.getActionCommand())) 
           JTextField textField =
             (JTextField)e.getSource();
            String memStartString = textField.getText();
            update(memStartString);
    public void update(String temp)
        frame.setText(temp);
    //Create a new internal frame.
    protected JTextArea createFrame() {
        JInternalFrame frame = new JInternalFrame("Memory",true,true,true,true);      
        frame.setSize(650, 500);
        frame.setVisible(true);
        frame.setLocation(200, 0);
        desktop.add(frame);  
        JTextArea textArea = new JTextArea();
        frame.getContentPane().add("Center", textArea);
        textArea.setFont(new Font("SansSerif", Font.PLAIN, 12));
        textArea.setVisible(true);
        textArea.setText("Initial Text");
        return textArea;
    //Quit the application.
    protected void quit() {
        System.exit(0);
    public static void main(String[] args) {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);
        //Create and set up the window.
        InternalFrameDemo frame = new InternalFrameDemo();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Display the window.
        frame.setVisible(true);
class MyInternalFrame extends JInternalFrame {
    static int openFrameCount = 0;
    static final int xOffset = 30, yOffset = 30;
    public MyInternalFrame() {
        super("Document #" + (++openFrameCount),
              true, //resizable
              true, //closable
              true, //maximizable
              true);//iconifiable
        //...Create the GUI and put it in the window...
        //...Then set the window size or call pack...
        setSize(300,300);
        //Set the window's location.
        setLocation(xOffset*openFrameCount, yOffset*openFrameCount);
}Note the e.getSource() change in the ActionListener.