public List getMessages(Topic topic) 
{
            List ret;
            if (messagesMap.containsKey(topic)) {
                ret = (List) messagesMap.get(topic);
            } else {
                ret = Collections.EMPTY_LIST;
            }
            return Collections.unmodifiableList(ret);
}

 public boolean isListeningTo(Topic topic) 
{
            return messagesMap.containsKey(topic);
}

 public synchronized  void onMessage(Message message) 
{
            try {
                Destination dest = message.getJMSDestination();
                List messages = null;
                if (!messagesMap.containsKey(dest)) {
                    register((Topic) dest);
                }
                messages = (List) messagesMap.get(dest);
                if (!messages.contains(message)) {
                    messages.add(message);
                }
                messagesMap.put(dest, messages);
            } catch (JMSException e) {
                log.error(e.getMessage(), e);
            }
}

 public  void register(Topic topic) 
{
            if (!messagesMap.containsKey(topic)) {
                List messages = new ArrayList();
                messagesMap.put(topic, messages);
            }
}