Swing Decoupling example

public class MainClass {

    public static void main(String[] args) {
        ExportFunction exporter = new ExportFunction();
        exporter.perform();
    }

}

public class ExportFunction implements ActionPerformedListener {

    private ExportUIDialog uiDialog;

    public void perform() {
        uiDialog = new ExportUIDialog();
        uiDialog.addActionPerformedListener(this);

        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                uiDialog.pack();
                uiDialog.setVisible(true);
            }
        });

    }

    @Override
    public void actionPerformed(int action) {
        if (ActionPerformedListener.STARTJOB == action) {
            ExportJob exportJob = new ExportJob();
            exportJob.addJobFinishedListener(uiDialog);
            exportJob.addLogListener(uiDialog);
            exportJob.start();
        }
    }

}

public class ExportJob extends Thread {

    private List<LogListener> logListeners = new ArrayList<LogListener>();

    private List<JobFinishedListener> jobDoneListeners = new ArrayList<JobFinishedListener>();

    public void addJobFinishedListener(JobFinishedListener listener) {
        jobDoneListeners.add(listener);
    }

    public void addLogListener(LogListener listener) {
        logListeners.add(listener);
    }

    @Override
    public void run() {

        // do some excel creating stuff
        try {
            fireLogListener("Job started");
            Thread.sleep(1000);
            fireLogListener("Excel Sheet 1 created");
            Thread.sleep(1000);
            fireLogListener("Excel Sheet 2 created");
            Thread.sleep(1000);
            fireJobFinishedListener("Here comes your Excel Sheet: Hokus Pokus!");
            Thread.sleep(500);
            fireLogListener("Job finished successfully.");
        } catch (InterruptedException e) {
            fireErrorOccuredListener(e);
        }

    }

    private void fireLogListener(final String message) {
        for (final LogListener listener : logListeners) {
            if (listener.shouldRunInUIThread()) {
                SwingUtilities.invokeLater(new Runnable() {

                    @Override
                    public void run() {
                        listener.reportLogging(message);
                    }
                });
            } else {
                listener.reportLogging(message);
            }
        }
    }

    private void fireJobFinishedListener(final String resultMessage) {
        for (final JobFinishedListener listener : jobDoneListeners) {
            if (listener.shouldRunInUIThread()) {
                SwingUtilities.invokeLater(new Runnable() {

                    @Override
                    public void run() {
                        listener.jobDone(resultMessage);
                    }
                });
            } else {
                listener.jobDone(resultMessage);
            }
        }
    }

    private void fireErrorOccuredListener(Exception e) {
        // demonstrating purpose
    }
}

public interface ActionPerformedListener {

    public static final int STARTJOB = 0;

    public static final int CANCELJOB = 1;

    public void actionPerformed(int action);

}


public interface JobFinishedListener extends ThreadListener {

    public void jobDone(Object result);

}


public interface LogListener extends ThreadListener{

    public void reportLogging(String message);

}

public interface ThreadListener {

    public boolean shouldRunInUIThread();

}

public class ExportUIDialog extends JDialog implements LogListener,
        JobFinishedListener {

    private static final long serialVersionUID = 8349630311908151734L;

    private List<ActionPerformedListener> actionListeners = new ArrayList<>();

    private JLabel label;

    private JList<String> list;

    public ExportUIDialog() {
        initGui();
    }

    public void addActionPerformedListener(ActionPerformedListener listener) {
        actionListeners.add(listener);
    }

    private void initGui() {
        setPreferredSize(new Dimension(400, 400));
        setLayout(new GridBagLayout());

        JButton button = new JButton("Save to Excel");
        button.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent arg0) {
                if (startConditionsFulfilled()) {
                    fireActionListener(ActionPerformedListener.STARTJOB);
                }
            }

        });
        GridBagConstraints cons = new GridBagConstraints();
        cons.gridx = 0;
        cons.gridy = 0;
        add(button, cons);

        label = new JLabel("ResultLabel");
        cons.gridy = 2;
        add(label, cons);

        list = new JList<String>();
        list.setVisibleRowCount(5);
        list.setModel(new DefaultListModel<String>());
        cons.gridy = 1;
        cons.fill = GridBagConstraints.BOTH;
        add(list, cons);

    }

    private void fireActionListener(int action) {
        for (ActionPerformedListener listener : actionListeners) {
            listener.actionPerformed(action);
        }
    }

    private boolean startConditionsFulfilled() {
        // do some UI prerequisites checks then tell the interface the
        // action can be performed.
        return true;
    }

    @Override
    public boolean shouldRunInUIThread() {
        // inherited from listener interface. This method is called from
        // Business logic to decide whether SwingUtilies.invokeLater is
        // necessary or not.
        return true;
    }

    @Override
    public void reportLogging(String message) {
        ((DefaultListModel<String>) list.getModel()).addElement(message);
    }

    @Override
    public void jobDone(Object result) {
        if (result instanceof String) {
            label.setText((String) result);
        }
    }

}