public synchronized MessageIdGenerator getGenerator(String serverId, ConnectionDelegate cd)
public synchronized MessageIdGenerator getGenerator(String serverId, ConnectionFactoryDelegate cfd)
   public synchronized MessageIdGenerator getGenerator(String serverId, ConnectionDelegate cd)      throws JMSException   {      Holder h = (Holder)holders.get(serverId);      if (h == null)      {         h = new Holder(new MessageIdGenerator(cd, BLOCK_SIZE));         holders.put(serverId, h);      }      else      {         h.refCount++;      }      return h.generator;   }