Java Swing: Using a Document Listener to Handle the Return Key

Question

I have a document listener that works just fine. However, I'd like to add some functionality to it so that when the user hits the Enter key, the focus shifts to another object. I can't figure out how to trap this. Here is my code:

txtNum1.getDocument().addDocumentListener(new DocumentListener() {

            @Override
            public void insertUpdate(DocumentEvent e) {
                setAnswer(e);
            }

            @Override
            public void removeUpdate(DocumentEvent e) {
                setAnswer(e);
            }

            @Override
            public void changedUpdate(DocumentEvent e) {
                setAnswer(e);
            }

            private void setAnswer(DocumentEvent e) {
                if (txtNum1.getText().equals("")) {
                    num1 = 0;
                } else {
                    num1 = Integer.parseInt(txtNum1.getText());
                }
                calcAnswer();
                System.out.println(e); //trying to output the event 'Enter'
            }

I can do this with a key listener, but I've been scolded on this site before about using that approach, so I'm trying to learn this the correct way.

Thanks!

EDIT: Per the suggestions below, I added the following code, but it seems to have no effect. Can anyone see what I am missing? Thanks!

/* If the user hits the Enter key, we want the focus to shift to
 * the next text field */
txtNum1.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        txtNum2.requestFocus();
    }
});

Answer 1

On a JTextfield, you can trap the Enter key simply by adding an ActionListener. It will get fired when the users types enter