Beyond Message Dialog

public class BaseDialog extends JDialog {

    protected BaseDialog(Frame owner, String title) {
        super(owner, title, true); 
    }

    protected boolean dataIsValid() { return true; }

    protected void setModelFromView() {}

    protected JButton stdOKButton() {
        JButton button = new JButton("OK");

        button.setMnemonic('O');
        getRootPane().setDefaultButton(button);
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (dataIsValid()) {
                    setModelFromView();
                    setVisible(false);
                }
            }
        });
        return button;
    }

    protected JButton stdCancelButton() {
        JButton button = new JButton("Cancel");

        button.setMnemonic('C');
        button.setDefaultCapable(false);
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                setVisible(false);
            }
        });
        return button;
    }

private void doExampleDialog() {
    JDialog dialog = new ExampleDialog(frame, data);
    dialog.setVisible(true);
}

public class ExampleDialog extends BaseDialog {

    private SomeClass  data;
    private JTextField nameText;
    private JTextField phoneText;

    public ExampleDialog(Frame owner, SomeClass data) {
        super(owner, "Exemplary Dialog");

        this.data = data;
        createComponents();
        setViewFromModel();
        layoutComponents();
        setLocationRelativeTo(owner);
    }

    // data validation -- note chaining of methods
    protected boolean dataIsValid() {
        return nameIsOK() && phoneIsOK();
    }

    // this only gets called if the user clicks OK
    protected void setModelFromView() {
        data.setName(nameText.getText());
        data.setPhone(phoneText.getText());
    }

    // use a method like this to init your components
    private void setViewFromModel() {
        nameText.setText(data.getName());
        phoneText.setText(data.getPhone());
    }

    private boolean nameIsOK() {
        if (nameText.getText().length() > 0) {
            return true;
        }
        showErrorMsg("You must enter a name.");
        nameText.requestFocus();
        return false;
    }

    private boolean phoneIsOK() {
        if (phoneText.getText().length() > 0) {
            return true;
        }
        showErrorMsg("You must enter a phone number.");
        phoneText.requestFocus();
        return false;
    }