Modal dialog issue

Question

I have subclassed JDialog in way that permits me to use it like this: String data = DialogUI.getData(...);
However, it seams as if I have two conflicting requirements. I want the dialog to block until the user has made a selection. Then, the selection should be returned as illustrated. However, I want the dialog to close if they move to a different field.
Is there a way (a hack) to close a modal dialog if the user clicks some outside the boundaries?
If I have to make it non-modal, is there a way to make the dialog return a value when the dialog is closed?
Also, does the following code make since, from an architecture and design view point?
Next
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Insets;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
class DialogUI extends JDialog {
  private JButton _btnOk = null;
  private JPanel _pnlMain = null;
  private JPanel _pnlSouth = null;
  protected JPanel _pnlCenter = null;
  private String _result;
  public DialogUI(Frame frame){
    super(frame, "", true);
    _pnlSouth = new JPanel();
    _pnlSouth.setPreferredSize(new Dimension(0, 40));
    _pnlSouth.setMinimumSize(new Dimension(0, 0));
    _pnlSouth.setMaximumSize(new Dimension(0, 0));
    _pnlCenter = new JPanel();
    _pnlMain = new JPanel();
    _pnlCenter.setOpaque(true);
    _pnlMain.setLayout(new BorderLayout());
    _pnlMain.add(_pnlSouth, BorderLayout.SOUTH);
    _pnlMain.add(_pnlCenter, BorderLayout.CENTER);
    BoxLayout layout = new BoxLayout(_pnlSouth, BoxLayout.X_AXIS);
    _pnlSouth.setLayout(layout);
    _btnOk = new JButton("OK");
    _btnOk.setPreferredSize(new Dimension(50, 0));
    _btnOk.setText("OK");
    _btnOk.setActionCommand("OK");
    _btnOk.setMargin(new Insets(1,0,1,0));
    _pnlSouth.add(Box.createHorizontalGlue());
    _pnlSouth.add(_btnOk, null);
    this.getContentPane().add(_pnlMain);
    _btnOk.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent event){
        _result = String.valueOf(new Date());
        dispose();
  public void open(){
    setSize(new Dimension(200, 100));
    setVisible(true);
  public static String getData(JComponent invoker) throws Exception{
    Frame frame = (Frame)javax.swing.SwingUtilities.getRoot(invoker);
    DialogUI dsw = new DialogUI(frame);
    dsw.setUndecorated(true);
    Point p = new Point();
    if(invoker != null){
      p.x = invoker.getLocationOnScreen().x;
      p.y = invoker.getLocationOnScreen().y + invoker.getHeight();
      dsw.setLocation(p);
    dsw.open();
    return dsw._result;
public class TextMP extends JPanel {
  private JTextField _text;
  private JButton _button;
  public TextMP() {
    _text = new JTextField();
    _button = new JButton("X");
    setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
    add(_text);
    add(_button);
  public JButton getButton() {
    return _button;
  public JTextField getText() {
    return _text;
  public static void main(String[] args) {
    final TextMP t = new TextMP();
    t.getButton().addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent arg0) {
        try{
          String data = DialogUI.getData(t.getButton());
          t.getText().setText(data);
        catch(Exception e){
          e.printStackTrace();
    JFrame frame = new JFrame();
    frame.getContentPane().add(t);
    frame.setSize(400, 300);
    frame.setVisible(true);
}

Answer 1

You should decide what is more important - forcing the end user to enter something, or allowing a default value.
If you do the former, then keep it modal. If the later, then non-modal and default the field.
I did not read through your code and so I don't know what you are trying to design. But I will say that it makes more sense in general (thinking of how most forms are designed - whether they be applications for the desktop, or the web) you allow the user to navigate over the form and enter or not at will. Then when some event is triggered - often a button being pressed - then you validate the entire form (or part of it if it is embedded in larger unit) and force entry or default depending on needs.
~Bill