What is the best way to implement a timer that will be stopped and restarted in a Java Swing Application?

Ok, I'm working on my final dilemna for my project. The project is an IPv4 endpoint updater for TunnelBroker's IPv6 tunnel. I have everything working, except for the timer. It works, however if the user disables the "automatic update" and reenables it, the application crashes. I need the timer to be on an thread outside of the EDT (in such a way that it can be destroyed and recreated when the user unchecks/checks the automatic update feature or changes the amount of time between updates).

What I'm pasting here is the code for the checkbox that handles automatic updates, and the timer class. Hopefully this will be enough to get an answer on how to do this (I'm thinking either it needs to be a worker, or use multi-threading--even though only one timer will be active).

 private void jCheckBox1ItemStateChanged(java.awt.event.ItemEvent evt) {                                            
    // TODO add your handling code here:
    // if selected, then run timer for auto update
    // set time textbox to setEditable(true) and get the time from it.
    // else cancel timer.  Try doing this on different
    // class to prevent errors from happening on reselect.
    int updateAutoTime = 0;


    if (jCheckBox1.isSelected())
    {
        updateAutoTime = Integer.parseInt(jTextField4.getText())*60*1000;
        if (updateAutoTime < 3600000)
        {
            updateAutoTime = 3600000;
            jTextField4.setText(new Integer(updateAutoTime/60/1000).toString());
        }
        updateTimer.scheduleAtFixedRate(new TimerTask() {
    public void run()
    {
        // Task h开发者_如何学编程ere ...
        if (jRadioButton1.isSelected())
        {
            newIPAddress = GetIP.getIPAddress();
        }
        else
        {
            newIPAddress = jTextField3.getText();
        }
         strUsername = jTextField1.getText();
         jPasswordField1.selectAll();
         strPassword = jPasswordField1.getSelectedText().toString();
         strTunnelID = jTextField2.getText();
         strIPAddress = newIPAddress;
         if (!newIPAddress.equals(oldIPAddress))
         {
             //fire the tunnelbroker updater class
             updateIP.setIPAddress(strUsername, strPassword, strTunnelID, strIPAddress);
             oldIPAddress = newIPAddress;
             jLabel8.setText(newIPAddress);
             serverStatus = updateIP.getStatus().toString();
             jLabel6.setText(serverStatus);
         }
         else
         {
             serverStatus = "No IP Update was needed.";
             jLabel6.setText(serverStatus);
         }
        }
}, 0, updateAutoTime);

    }
    else
    {
       updateTimer.cancel();
       System.out.println("Timer cancelled");
       System.out.println("Purged {updateTimer.purge()} tasks.");
    }


}     

As I mentioned, this works once. But if the user deselects the checkbox, it won't work again. And the user can't change the value in jTextField4 after they select the checkbox.

So, what I'm looking for is this:

1. How to make this so that user can select and deselect the checkbox as they want (even if it's multiple times in a row).
2. How to make this so the user can change the value in jTextField4, and have it automatically cancel the current timer, and start a new one with the new value (I haven't done anything with the jTextField4 at all, so I'll have to create an event to cover it later).

Thanks, and have a great day:) Patrick.

Perhaps this task would be better suited to a javax.swing.Timer. See Timer.restart() for details.

Note that Timer is relatively inaccurate over long time periods. One way to account for that is to have it repeat frequently but perform it's assigned task only one a certain time has been reached or passed.

Would I be able to wrap everything in the "task" portion of the call to Swing Timer, or do I have to create another class that handles the task?

You might want to wrap the grunt work in a SwingWorker to ensure the EDT is not blocked.

..I'm assuming that I would have to create the timer as a class-level declaration .. correct?

Yes, that is what I was thinking.