void acknowledge(String messageID, Transaction tx)
synchronized void acknowledge(String messageID, Transaction tx)
   void acknowledge(String messageID, Transaction tx)   {      if (log.isTraceEnabled()) { log.trace("acknowledging " + messageID); }      try      {         for(Iterator i = deliveries.iterator(); i.hasNext(); )         {            Delivery d = (Delivery)i.next();            if (d.getReference().getMessageID().equals(messageID))            {               d.acknowledge(tx);               i.remove();            }         }      }      catch(Throwable t)      {         log.error("Message " + messageID + "cannot be acknowledged to the source");      }   }