Figuring out of a step has been completed

Question

I posted this here since I am using SwingWorker for my threading, but I may have chosen the wrong section like always. First, here is my code:
    class Task extends SwingWorker<Void, Void>
        @Override
        public Void doInBackground ()
            try
                /* doInBackground is a 2nd thread that connects to the database to download the library
                 * that we will store locally on the system. During the download process, doInBackground
                 * also updates the progress bar and status label so the user knows what is going on.
                 * When this method is called, our ArrayList is cleared to ensure we don't get dupplicate
                 * entries. Each row from the database is stored in an index and the information is
                 * seperated by a tab delimeter. We will use tab spacing to space out the artist, title,
                 * and path of the audio file.
                al.clear ();
                progressLabel.setText ("Connecting to database...");
                downloadProgress.setIndeterminate (true);
                Connection connection = Database.sqlConnection ();
                progressLabel.setText ("Downloading library list...");
                downloadProgress.setIndeterminate (false);
                Statement stmt = connection.createStatement (ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
                String sql = "SELECT * FROM audio";
                PreparedStatement pstmt = connection.prepareStatement (sql);
                ResultSet rs = pstmt.executeQuery ();
                /* Let's get the row count so we can make an accurate progress bar.  First, we must move the cursor
                 * of the ResultSet to the last row, and by using getRow(), we can return an INT of the last row
                 * count. We will then store that INT into 'rowcount'. After doing so, we much move the cursor back
                 * to the beginning of the ResultSet. Otherwise, we will not be able to get any row information since
                 * we are at the last row.
                rs.last ();
                int rowcount = rs.getRow ();
                downloadProgress.setMaximum (rowcount);
                rs.beforeFirst ();
                /* Now we are ready to read the row information from the database. Starting at the beginning of the
                 * ResultSet, we will get the information from each row and store it in an ArrayList. We will then
                 * use the ArrayList to write our downloaded library to a file. We are using an ArrayList due to
                 * the fact that we will not be able to accurately specify the number of indexes needed, hence
                 * why we are not using a typical Array.
                while (rs.next ())
                    al.add (rs.getInt ("id") + "\t" + rs.getString ("artist") + "\t" + rs.getString ("title") + "\t" + rs.getString ("path") + "\t" + rs.getInt ("length"));
                    downloadProgress.setValue (downloadProgress.getValue () + 1);
                Database.closeResultSet (rs);
                Database.closePreparedStatement (pstmt);
                Database.closeStatement (stmt);
                Database.closeConnection (connection);
                System.out.println("The size of the ArrayList is " + al.size () + " indexes");
                /* Now that we have downloaded the list from the server, libraryCreator will
                 * take the array and write it to library.lst to make our music list locally
                 * accessable. This will reduce us to only 1 SQL connection instead of needing
                 * a connection everytime the user wants to search for a song.
                libraryCreator ();
            catch (SQLException e)
                // Could not connect to the database
                JOptionPane.showMessageDialog (null,"Unable to connect to the database.\n\nPlease check your network connection. "
                        + " Contact the administrator if the problem persists.", "Connection Error",
                        JOptionPane.ERROR_MESSAGE);
                System.out.println ("Error: " + e.getMessage ());
            return null;
         * Executed in event dispatching thread
        @Override
        public void done ()
            try
                Toolkit.getDefaultToolkit ().beep ();
                setCursor (null); //turn off the wait cursor
                progressLabel.setText ("Completed.");
                continueButton.setEnabled (true);
            catch (Exception e)
                System.out.println(e);
    }What's going on is, well everything is working correctly, but I want to be a bit more accurate with my error reporting. Currently, the application is connecting to a database, selecting all the rows from a table, getting the total number of rows so I can accurately update my progress bar, close my statements and connection, and then call a method to do some file writing. With the way it is right now, say I am unable to connect to the database due to lack of network connection or whatever, I still throw an exception and display a JOptionPane telling the user that there was a connection issue, but even with the exception being throw, my progress indicator still goes on to finish up and say "Completed" when it really isn't completed.
Within my done() method, how can I go about seeing if an exception has been thrown in my Database class, and if so, change the progressLabel to "Incomplete" rather than "Complete"? Hopefully this makes sense.

Answer 1

Hi,
introduce a flag
class Task extends SwingWorker<Void, Void> {
  private boolean completed = false;
...into your Task class and set it to true, when your task is finished, inside the doInBackground method right after you called libraryCreator(), e.g.
     libraryCreator();
     completed = true;
   } catch (SQLException e) {
...Change the done method so that it checks that flag. For example:
* Executed in event dispatching thread
@Override
public void done() {
  try {
    Toolkit.getDefaultToolkit().beep();
    setCursor(null); //turn off the wait cursor
    if ( completed ) {
      progressLabel.setText("Completed.");
      continueButton.setEnabled(true);
    } else {
      progressLabel.setText("An error occured.");
      continueButton.setEnabled(false);
  } catch (Exception e) {
    System.out.println(e);
}- Michael