SwingWorker asynchronous PropertyChangeEvent problems

Question

I'm using a SwingWorker to execute a task that I am keeping progress on. I have a JDialog that I show and dispose of based on events from the SwingWorker. These events are generated asynchronously on the EDT which is fine. I understand that it may be the case I could call setProgress a few times before a PropertyChangeEvent actually happens, however what I don't understand is why a "state" event is never making it as the event when the SwingWorker completes. If I cancel the task it will reach it, but when it finishes by itself there is nothing. This state event should be getting fired and listened to and handled on the EDT but its not. Attached is my code for three classes and an example of how to use it. Basically it just takes a .lst whose format is an IP address on each line, nothing else.
public class OpenSwingWorker extends SwingWorker<Object[], Object> {
    private FILETYPE _fileType = null;
    private File[] _files = null;
    private DefaultListModel _listModel = null;
    private List<Object> _objects = null;
    private int _progress = 0;
    public OpenSwingWorker(FILETYPE fileType, File[] files, ListModel listModel) {
        _fileType = fileType;
        _files = files;
        _listModel = (DefaultListModel) listModel;
        _objects = new ArrayList<Object>();
    @Override
    protected Object[] doInBackground() {
        int progress = 0;
        if (_fileType == FILETYPE.LST) {
            BufferedReader bufferedReader = null;
            String line = null;
            for (File file : _files) {
                if (isCancelled()) {
                    break;
                try {
                    bufferedReader = new BufferedReader(new FileReader(file));
                    while ((line = bufferedReader.readLine()) != null) {
                        InetAddress inetAddress = InetAddress.getByName(line);
                        _objects.add(inetAddress);
                        publish(inetAddress);
                } catch (FileNotFoundException ex) {
                    Logger.getLogger(OpenSwingWorker.class.getName()).log(Level.SEVERE, null, ex);
                } catch (IOException ex) {
                    Logger.getLogger(OpenSwingWorker.class.getName()).log(Level.SEVERE, null, ex);
                } catch (Exception ex) {
                    Logger.getLogger(OpenSwingWorker.class.getName()).log(Level.SEVERE, null, ex);
                } finally {
                    try {
                        bufferedReader.close();
                    } catch (IOException ex) {
                        Logger.getLogger(OpenSwingWorker.class.getName()).log(Level.SEVERE, null, ex);
                setProgress(++_progress * 100 / _files.length);
        } else if (_fileType == FILETYPE.MSG) {
            MsgParser msgParser = Main.getMsgParser();
            for (File file : _files) {
                if (isCancelled()) {
                    break;
                try {
                    MessageRecord messageRecord = new MessageRecord(msgParser.parseMsg(file));
                    _objects.add(messageRecord);
                    publish(messageRecord);
                } catch (IOException ex) {
                    Logger.getLogger(OpenSwingWorker.class.getName()).log(Level.SEVERE, null, ex);
                } catch (UnsupportedOperationException ex) {
                    Logger.getLogger(OpenSwingWorker.class.getName()).log(Level.SEVERE, null, ex);
                setProgress(++progress * 100 / _files.length);
        return _objects.toArray();
    @Override
    protected void process(List<Object> chunks) {
        for (Object object : chunks) {
            _listModel.addElement(object);
public class SwingWorkerPropertyChangeListener implements PropertyChangeListener {
    private ProgressJDialog _progressJDialog = null;
    private SwingWorker _swingWorker = null;
    public SwingWorkerPropertyChangeListener(ProgressJDialog progressJDialog, SwingWorker swingWorker) {
        _progressJDialog = progressJDialog;
        _swingWorker = swingWorker;
    public void propertyChange(PropertyChangeEvent evt) {
        String propertyName = evt.getPropertyName();
        if (propertyName.equals("state")) {
            SwingWorker.StateValue stateValue = (StateValue) evt.getNewValue();
            if (stateValue.equals(SwingWorker.StateValue.STARTED)) {
                _progressJDialog.setVisible(true);
            } else if (stateValue.equals(SwingWorker.StateValue.DONE)) {
                _progressJDialog.dispose();
        } else if (propertyName.equals("progress")) {           
            if (_progressJDialog.isCancelled()) {
                _swingWorker.cancel(true);
            } else {
                _progressJDialog.setProgress((Integer) evt.getNewValue());
public class ProgressJDialog extends JDialog {
    private boolean _cancelled = false;
    private JButton _jButton = null;
    private JProgressBar _jProgressBar = null;
    public ProgressJDialog(boolean indeterminate, String taskName) {
        super((JDialog) null, "Performing Task...", true);
        _jProgressBar = new JProgressBar();
        _jProgressBar.setBorder(BorderFactory.createTitledBorder(taskName));
        _jProgressBar.setIndeterminate(indeterminate);
        _jProgressBar.setStringPainted(true);
        initComponents();
    private void createJButton() {
        _jButton = new JButton("Cancel");
        _jButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                dispose();
        _jButton.setMnemonic(KeyEvent.VK_C);
    private void initComponents() {
        createJButton();
        add(_jProgressBar, BorderLayout.CENTER);
        add(_jButton, BorderLayout.LINE_END);
        addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosed(WindowEvent e) {
                _cancelled = true;
        pack();
        setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
    public boolean isCancelled() {
        return _cancelled;
    public void setProgress(int progress) {
        _jProgressBar.setValue(progress);
/* EXAMPLE USAGE BELOW */
if (jFileChooser1.showOpenDialog(this) == JFileChooser.APPROVE_OPTION) {
            SwingWorker openSwingWorker = new OpenSwingWorker(Main.FILETYPE.valueOf(jFileChooser1.getFileFilter().getDescription()), jFileChooser1.getSelectedFiles(), jList1.getModel());
            openSwingWorker.addPropertyChangeListener(new SwingWorkerPropertyChangeListener(new ProgressJDialog(false, "Opening files..."), openSwingWorker));
            openSwingWorker.execute();
}

Answer 1

I figured out the problem. It's not that the PropertyChangeEvent's weren't occuring it's that they were occuring too quickly. I placed a sleep before setting progress and now it works nicely. I hope if anyone else runs into this problem I save them some time this was bugging me forever. Thanks again.