Sending a notification using MDB, javamail and a scheduler

Question

Hi,
I have this following scenario.
I need to send an email notification to user B from user A.
So, user A fills the required details and adds the notification object to jms/queue
In MessageDriveBean onMessage(), i am getting the notification object from the queue
and i am able to send an email using JavaMail.
Everything is working fine.
Now , if under any conditions, sending notification fails, I need to implement
a scheduler which should try to send the notification within the specified time interval
and if not again adds the notification object to queue.
Can you please help me to implement a scheduler?
Thanks in advance!!!

Answer 1

Have a look at this simple schedular below, test by changing the method onMessage() to a main method
and simulate.
Hope this help
Ivo Sumelong
* @author isumelong
public class MessageFromQueueMDBHandler {
     * @param args the command line arguments
    public  void onMessage() {
         MessageFromQueueMDBHandler m=new MessageFromQueueMDBHandler();
         m.hanldeMessageFromQuue();
  public synchronized  void  hanldeMessageFromQuue()
// Thread.sleep() is not good since its a static method this
// why wait will be best since it controls only the thread
// that received the messgae from the queue
//schedular information read from database
// numberOfTrials,waitingTimeBeforeResending;
// advantage: schedular behaviour could be changed at run time
int numberOfTrials=4;// from database
      try {
            for(int i=0;i<System.currentTimeMillis();i++)
                if(sendMail())
                break;
                if(i==numberOfTrials)
                   // send an message to queue
                   sendMessageToQueue();
                notifyAll();
                     break;
              long waitingTimeBeforeResending=1000;// from database
            this.wait(waitingTimeBeforeResending);
        } catch (InterruptedException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
  private boolean sendMail()
  // java mail API accesses
      return true;
   private boolean sendMessageToQueue()
  // java JMS API accesses
      return true;
}