Universal Messaging 10.1 | Developer Guide | Enterprise APIs | Enterprise Developer's Guide for Java | Publish / Subscribe Using DataStreams and DataGroups | DataStreamListener
If a nSession is created with a nDataStreamListener then it will receive asynchronous callbacks via the onMessage implementation of the nDataStreamListener interface. The nDataStreamListener will receive events when:
*An event is published directly to this particular nDataStream
*An event is published to any nDataGroup which contains this nDataStream
*An event is published to an nDataGroup which contains a nested nDataGroup containing this nDataStream
*An example of how to create a session with an nDataStreamListener interface is shown below:

public class DataGroupClient implements nDataStreamListener{

nSession mySession;

public DataGroupClient( String realmURLs){
nSessionAttributes nsa = new nSessionAttributes(realmURLs);
mySession = nSessionFactory.create(nsa, this);

// nDataStreamListener Implementation

//Callback received when event is available
public void onMessage(nConsumeEvent event){

//some code to process the message