Determine the number of consumers

[Cosmin Marginean]

Hi,  

Is there a reliable way to determine the number of consumers for a topic (or at 
least the number of consumer groups).
I’m using Kafka 0.9.0.0 and both the ones below return empty sets

zkUtils.getAllConsumerGroupsForTopic(topic);

OR

zkUtils.getConsumerGroups();

Thanks in advance
Cos