@Override
 public SampleArrayFxList getObject() throws Exception {
   if (null == instance) {
     instance = new SampleArrayFxList(topicName);
     instance.start(subscriber, eventLoop, expression, params, qosLibrary, qosProfile);
   }
   return instance;
 }
 @Override
 public void destroy() throws Exception {
   if (null != instance) {
     instance.stop();
   }
 }