@Override
      public StringBuilder doInBackground() throws IOException, InterruptedException
      {
         int lineNumber = 0;
         Scanner in = new Scanner(new FileInputStream(file));
         while (in.hasNextLine())
         {
            String line = in.nextLine();
            lineNumber++;
            text.append(line);
            text.append("\n");
            ProgressData data = new ProgressData();
            data.number = lineNumber;
            data.line = line;
            publish(data);
            Thread.sleep(1); // to test cancellation; no need to do this in your programs
         }
         return text;
      }