public Disruptor createSingleDisruptor(String topic) {
		TreeSet handlers = getHandles(topic);
		if (handlers == null)
			return null;
		Disruptor dw = createSingleDw(topic);
		Disruptor disruptor = addEventMessageHandler(dw, topic, handlers);
		if (disruptor == null)
			return null;
		disruptor.start();
		return disruptor;
	}
public Disruptor createSingleDisruptor ( String topic ) { TreeSet handlers = getHandles ( topic ) ; if ( handlers == null ) return null ; Disruptor dw = createSingleDw ( topic ) ; Disruptor disruptor = addEventMessageHandler ( dw , topic , handlers ) ; if ( disruptor == null ) return null ; disruptor . start ( ) ; return disruptor ; }
single producer :single consumer

no lock

@param topic
@return