JOptionpane + JDialog (non-modal) get the return value

I have a non-modal dialog with two input text fields shown with the JOptionPane with OK and CANCEL buttons. I show the dialog as below.

        JTextField field_1 = new JTextField("Field 1");
        JTextField field_2 = new JTextField("Field 2");

        Object[] inputField = new Object[] { "Input 1", field_1,
                "Input_2", field_2 };

        JOptionPane optionPane = new JOptionPane(inputField,
                JOptionPane.QUESTION_MESSAGE, JOptionPane.OK_CANCEL_OPTION);
        JDialog dialog = optionPane.createDialog(null, "Input Dialog");
        dialog.setModal(false);
        dialog.setVisible(true);

How can i get the return value from the dialog? Means i need to get whether Ok or CANCEL button is pressed. How can achieve this?

One way would be to add a ComponentListener to the dialog and listen for its visibility to change,

dialog.addComponentListener(new ComponentListener() {
    @Override
    public void componentResized(ComponentEvent e) { }

    @Override
    public void componentMoved(ComponentEvent e) { }

    @Override
    public void componentShown(ComponentEvent e) { }

    @Override
    public void componentHidden(ComponentEvent e) {
        if ((int) optionPane.getValue()
                == JOptionPane.YES_OPTION) {
            // do YES stuff...
        } else if ((int) optionPane.getValue()
                == JOptionPane.CANCEL_OPTION) {
            // do CANCEL stuff...
        } else {
            throw new IllegalStateException(
                    "Unexpected Option");
        }
    }
});

Note: you should probably use the ComponentAdapter instead; I'm showing the whole interface for illustration.