locking JTextField from external updates while editing

My GUI displays the data coming from the backend every 500ms. I'm having a race condition when it comes to editing fields. By the time the Action listener is invoked, the value from the backend overwrites whatever the user entered manually into a text field.

Is there a way to lock the field or use a semaphore or retrieve new value from elsewhere?

Thanks.

        JTextField tf = new JTextField();
        tf.setName("reg_r"+i);          
        tf.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                开发者_开发问答JTextField tf = (JTextField)e.getSource();

                //prints OLD value!
                System.err.println(tf.getText());

            }
        });

The solution i came up with is to detect when the text field is being edited and not update it.

JTextField tf = (JTextField) FrameUtils
                    .getComponentById(
                            instance.getContentPane(), "reg_r"
                                    + i);
            Component c = (Component) getFocusOwner();
            if (c == null || !tf.getName().equals(c.getName())) {
            // JTextField is not focused/being edited, proceed with update
            tf.setText(...);
            }