Notifying Methods to Shut Down in Servlets

See Tracking Service Request

To ensure a clean shutdown, your destroy method should not release any shared resources until all of the service requests have completed. One part of doing this is to check the service counter. Another part is to notify the long-running methods that it is time to shut down. For this notification, another field is required. The field should have the usual access methods:

public class ShutdownExample extends HttpServlet {
   private boolean shuttingDown;
   ...
   //Access methods for shuttingDown
   protected synchronized void setShuttingDown(boolean flag) {
      shuttingDown = flag;
   }
   protected synchronized boolean isShuttingDown() {
      return shuttingDown;
   }
}
 

An example of the destroy method using these fields to provide a clean shutdown follows:

public void destroy() {
   /* Check to see whether there are still service methods /*
   /* running, and if there are, tell them to stop. */
   if (numServices() > 0) {
      setShuttingDown(true);
   }

   /* Wait for the service methods to stop. */
   while(numServices() > 0) {
      try {
         Thread.sleep(interval);
      } catch (InterruptedException e) {
      }
   }
}