if (log.isDebugEnabled()) log.debug("Agent "+agent+" registered with the LinksEnablingService with advice="+defaultAdvice);
        private AgentEntry assureRegistered(MessageAddress agent) {            AgentEntry entry = (AgentEntry)agents.get(agent);	    if (entry == null) {	        entry = new AgentEntry(agent, defaultAdvice);                agents.put(agent, entry);		entry.observer = new AgentObserver(agent);	    }	    return entry;	}   