d.acknowledge(null);
if (d.isSelectorAccepted()) { d.acknowledge(null); } else { d.cancel(); }
   void acknowledgeAll() throws JMSException   {        try      {              for(Iterator i = deliveries.values().iterator(); i.hasNext(); )         {            SingleReceiverDelivery d = (SingleReceiverDelivery)i.next();            d.acknowledge(null);                 }         deliveries.clear();      }      catch(Throwable t)      {         throw new JBossJMSException("Failed to acknowledge deliveries", t);      }   }