code: public Disruptor createDisruptor(String topic) {
  		TreeSet handlers = getHandles(topic);
  		if (handlers == null)
  			return null;
  
  		Disruptor dw = createDw(topic);
  		Disruptor disruptor = addEventMessageHandler(dw, topic, handlers);
  		if (disruptor == null)
  			return null;
  		disruptor.start();
  		return disruptor;
  	}
docs: one topic one EventDisruptor
  
  @param topic
  @return