code: public synchronized List<LocalQueue> updatedQueues()
      {
      	List<LocalQueue> updatedQueues = new ArrayList<>(items.size());
      	for (int i = 0 ; i < items.size() ; i++)
          {
      		TransactionItem item = items.get(i);
              LocalQueue localQueue = item.getDestination();
              if (!updatedQueues.contains(localQueue))
                  updatedQueues.add(localQueue);
          }
      	
      	return updatedQueues;
      }
docs: Compute a list of queues that were updated in this transaction set