How to unsubscribe a RIC using EMA API OmmConsumerClient?

dimple.shah

Hi Team,

We are currently upgrading our application from RFA API to EMA API and we are facing issues while unsubscribing a RIC in some scenarios. We are using the OmmConsumerClient as explained in the examples. But while unsubscribing a RIC we are still getting updates for it in the form of UpdateMessage.

We request you to please provide a working example to unsubscribe a RIC in Java using this OmmConsumerClient.

class AppClient implements OmmConsumerClient

{

public void onRefreshMsg(RefreshMsg refreshMsg, OmmConsumerEvent event)

{

System.out.println(refreshMsg);

}

public void onUpdateMsg(UpdateMsg updateMsg, OmmConsumerEvent event)

{

System.out.println(updateMsg);

}

public void onStatusMsg(StatusMsg statusMsg, OmmConsumerEvent event)

{

System.out.println(statusMsg);

}

public void onGenericMsg(GenericMsg genericMsg, OmmConsumerEvent consumerEvent){}

public void onAckMsg(AckMsg ackMsg, OmmConsumerEvent consumerEvent){}

public void onAllMsg(Msg msg, OmmConsumerEvent consumerEvent){}

}

public class Consumer

{

public static void main(String[] args)

{

OmmConsumer consumer = null;

try

{

AppClient appClient = new AppClient();

OmmConsumerConfig config = EmaFactory.createOmmConsumerConfig();

consumer = EmaFactory.createOmmConsumer(config.host("localhost:14002").username("user"));

ReqMsg reqMsg = EmaFactory.createReqMsg();

consumer.registerClient(reqMsg.serviceName("DIRECT_FEED").name("IBM.N"), appClient);

Thread.sleep(60000); // API calls onRefreshMsg(), onUpdateMsg() and onStatusMsg()

}

catch (InterruptedException | OmmException excp)

{

System.out.println(excp.getMessage());

}

finally

{

if (consumer != null) consumer.uninitialize();

}

}

}

wasin.w

Hello @dimple.shah

Basically, the OmmConsumer.registerClient() method returns a handle which is a reference to the subscription RIC.

Once you get a handle, you can use OmmConsumer.unregister(handle) method to unsubscribe that RIC stream.

Example Code:

long handle = consumer.registerClient(EmaFactory.createReqMsg().serviceName("ELEKTRON_DD").name("JPY="), appClient, 0)


Thread.sleep(6000);      // API calls onRefreshMsg(), onUpdateMsg() and onStatusMsg()
System.out.println("Close Item request");
consumer.unregister(handle);
Thread.sleep(60000);     // API calls onRefreshMsg(), onUpdateMsg() and onStatusMsg()

If you are using Batch, the batch request message is always closed by the backend, and then the backend creates individual streams for each of the RICs and allocate a unique handle to each stream. You can get the item subscription handler from the OmmConsumerEvent.handler() method in the OmmConsumerClient class too.

Please see the full example code from the EMA Java ex300_MP_Close example.

Example Code:

class AppClient implements OmmConsumerClient{
    long numOfUpdates = 0;
    OmmConsumer _ommConsumer = null;
    
    void setOmmConsumer(OmmConsumer consumer){
        _ommConsumer = consumer;
    }


    public void onRefreshMsg(RefreshMsg refreshMsg, OmmConsumerEvent event){
        ....
    }
    
    public void onUpdateMsg(UpdateMsg updateMsg, OmmConsumerEvent event) {
        System.out.println("Item Name: " + (updateMsg.hasName() ? updateMsg.name() : "<not set>"));
        System.out.println("Service Name: " + (updateMsg.hasServiceName() ? updateMsg.serviceName() : "<not set>"));
        
        if (DataType.DataTypes.FIELD_LIST == updateMsg.payload().dataType())
            decode(updateMsg.payload().fieldList());
        
        System.out.println();
        
        // Close streaming request after receiving 3 update messages
        if (++numOfUpdates == 3){
            System.out.println("Close Item request");
            _ommConsumer.unregister(event.handle());


        }
    }

    public void onStatusMsg(StatusMsg statusMsg, OmmConsumerEvent event) {
        ...
    }
    
    ....

    void decode(FieldList fieldList){
        ....
    }


}
public class Consumer {
   public static void main(String[] args) {
      OmmConsumer consumer = null;
      try{
         AppClient appClient = new AppClient();
         consumer = EmaFactory.createOmmConsumer(EmaFactory.createOmmConsumerConfig().host("localhost:14002").username("user"));

        appClient.setOmmConsumer(consumer);

         ....
      }
   }
}