public boolean addReference(MessageReference ref) throws Throwable
public void addReference(MessageReference ref, Transaction tx) throws Throwable
   public boolean addReference(MessageReference ref) throws Throwable   {      boolean first;                   synchronized (refLock)      {                  ref.setOrdering(getNextReferenceOrdering());                        if (ref.isReliable() && recoverable)         {            //Reliable message in a recoverable state - also add to db            if (trace) { log.trace("adding " + ref + " to database non-transactionally"); }                        pm.addReference(channel.getChannelID(), ref, null);                     }                  first = addReferenceInMemory(ref);                                     }      return first;    }