code: public synchronized List<LocalQueue> updatedQueues( List<String> deliveredMessageIDs ) throws FFMQException
      {
      	int len = deliveredMessageIDs.size();
      	List<LocalQueue> updatedQueues = new ArrayList<>(len);
      	for(int n=0;n<len;n++)
      	{
      		String deliveredMessageID = deliveredMessageIDs.get(len-n-1);
      		
      		boolean found = false;
      		Iterator<TransactionItem> entries = items.iterator();
          	while (entries.hasNext())
      		{
          		TransactionItem item = entries.next();
          		if (item.getMessageId().equals(deliveredMessageID))
          		{
          			found = true;
          			
          			LocalQueue localQueue = item.getDestination();
                      if (!updatedQueues.contains(localQueue))
                          updatedQueues.add(localQueue);
  
          			break;
          		}
      		}
      		
      		if (!found)
      			throw new FFMQException("Message does not belong to transaction : "+deliveredMessageID,"INTERNAL_ERROR");
      	}
      	return updatedQueues;
      }
docs: Compute a list of queues that were updated in this transaction set