AutoClosePane

[Adam Richards]

I'm fine tuning a class that automatically closes a dialog if the user doesn't respond. I got it to work, but it seems awfully klutzy, so thought I'd see if anyone had any suggestions on ways to improve it. The code below is an extract from the class, but demonstrates the core functionality. For example, to display a confirmation dialog, you would construct the AutoclosePane object, then call confirmOrTimeout. Does anyone see any weaknesses in this code, or a way to make it shorter?

import java.awt.Component;
import java.awt.HeadlessException;
import javax.swing.JDialog;
import javax.swing.JOptionPane;
 
/**
 * Displays dialogs that close automatically after a specified length of time. 
 */
public class AutoclosePane
{
private final long timeout;
 
//----------------------------------------------------------------------------------------------
/**
 * Class constructor.
 * @param timeout Timeout period, in milliseconds.
 */
public AutoclosePane(long timeout)
{
   this.timeout = timeout;
}
//----------------------------------------------------------------------------------------------
/**
 * Displays a confirmation dialog.
 * @param message The message to display in the dialog.
 * @param title Dialog title (if <code>null</code>, default title will be used)
 * @return An integer indicating the option selected by the user, one of:<ul>
 * <li>{@link JOptionPane#CLOSED_OPTION} If timeout occurs</li>
 * <li>{@link JOptionPane#YES_OPTION}</li>
 * <li>{@link JOptionPane#NO_OPTION}</li>
 * <li>{@link JOptionPane#CANCEL_OPTION}</li>
 * </ul>
 */
public int confirmOrTimeout(String message, String title) throws HeadlessException
{
   JOptionPane pane = new JOptionPane(message, JOptionPane.QUESTION_MESSAGE, 
      JOptionPane.YES_NO_CANCEL_OPTION);
   return showWithTimeout(pane, null, title);
}
//----------------------------------------------------------------------------------------------
/**
 * Displays a dialog with an automatic timeout. The timeout value is set in the constructor.
 * @param pane The controlling pane.
 * @param parent Parent component (may be <code>null</code> :wink: 
 * @param title Dialog title.
 * @return One of the following:<ul>
 * <li>{@link JOptionPane#CLOSED_OPTION} If timeout occurs</li>
 * <li>{@link JOptionPane#CANCEL_OPTION}</li>
 * <li>{@link JOptionPane#YES_OPTION}</li>
 * <li>{@link JOptionPane#NO_OPTION}</li>
 * </ul>
 */
private int showWithTimeout(JOptionPane pane, Component parent, String title)
{
   final JDialog dialog = pane.createDialog(parent, title);
   Thread timeoutThread = new Thread()
   {
      public void run()
      {
         try { sleep(timeout); }
         catch (InterruptedException ex) { /* Fall through*/ }  // Ensure we close the dialog
         javax.swing.SwingUtilities.invokeLater(new Runnable() //   from the event dispatch
            { public void run() { dialog.hide(); } });            //   thread
      }
   };
   timeoutThread.start();
   dialog.show();
   Object selection = pane.getValue();                      // We get to this point when
   int result = JOptionPane.CLOSED_OPTION;                   // (1) The user makes a selection
   if (selection != null && selection instanceof Integer)        // or (2) the timeout thread closes
      result = ((Integer)selection).intValue();             // the dialog.
   return result;
}
//----------------------------------------------------------------------------------------------
}

[Ernest Friedman-Hill]

You could make it a little shorter and more idomatic by using a javax.swing.Timer to do the close-after-delay. But other than that, it is pretty short -- it's mostly comments.

[Adam Richards]

Thanks, Ernest. I pursued your suggestion & modified the class to use a Timer instead. The code ended up being shorter, & I was able to eliminate a
constructor to initialize the timeout value. Works like a charm now!