EMAJ: [OmmConsumer batch] Can I dynamiclly change the itemlist during running?

Regarding sample example370__MarketPrice__Batch

consumer  = EmaFactory.createOmmConsumer(EmaFactory.createOmmConsumerConfig().host("localhost:14002").username("user"));
            
ElementList batch = EmaFactory.createElementList();
OmmArray array = EmaFactory.createOmmArray();
            
array.add(EmaFactory.createOmmArrayEntry().ascii("TRI.N"));
array.add(EmaFactory.createOmmArrayEntry().ascii("IBM.N"));

batch.add(EmaFactory.createElementEntry().array(EmaRdm.ENAME_BATCH_ITEM_LIST, array));
            
consumer.registerClient(EmaFactory.createReqMsg().serviceName("DIRECT_FEED").payload(batch), appClient);

Can I change the content of ENAME_BATCH_ITEM_LIST after registerClient()?

Much appreciated for any suggestion!

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Accepted answers

pimchaya.wongrukun01

Hello @loy.longyi

If you mean to modify ENAME_BATCH_ITEM_LIST of the batch stream the application has opened (registerClient(..) has called already), based on my test it seems to be impossible. Since batch stream is closed after the batch steam request is sent to the server like the message below:

Item Name: <not set>
Service Name: API_ELEKTRON_EPD_RSSL
Item State: Closed / Ok / None / 'Stream closed for batch'

Hence, there is no batch stream to be modified. Then, ADS responds by sending the items as if they were opened individually like the diagram below:

When I tried to modify the batch stream, I got the following error:

Jan 20, 2020 10:34:22 AM com.thomsonreuters.ema.access.BatchItem modify
SEVERE: loggerMsg
    ClientName: BatchItem
    Severity: Error
    Text:     Invalid attempt to modify batch stream. Instance name='Consumer_1_1'.
loggerMsgEnd

If you want to add new RICs, you have to create a new batch request and call registerClient(..).

batch.png

All comments

pimchaya.wongrukun01

Hello @loy.longyi

Item Name: <not set>
Service Name: API_ELEKTRON_EPD_RSSL
Item State: Closed / Ok / None / 'Stream closed for batch'

Hence, there is no batch stream to be modified. Then, ADS responds by sending the items as if they were opened individually like the diagram below:

When I tried to modify the batch stream, I got the following error:

Jan 20, 2020 10:34:22 AM com.thomsonreuters.ema.access.BatchItem modify
SEVERE: loggerMsg
    ClientName: BatchItem
    Severity: Error
    Text:     Invalid attempt to modify batch stream. Instance name='Consumer_1_1'.
loggerMsgEnd

If you want to add new RICs, you have to create a new batch request and call registerClient(..).

batch.png

wasin.w V3

Hello @loy.longyi

You can not change the subscription RICs on existing item streams as mention by my colleague above.

You can pause-resume, change subscription View and increase-decrease the streams priority on existing streams with "reissue" function only.

pimchaya.wongrukun01

Hello @loy.longyi

For the example of reissue, please look into example301__MarketPrice__PriorityChange

veerapath.rungruengrayubkul

Batch Stream will be closed automatically after server receives a batch request. Consumer application will receive item response on individual streams. To remove subscription for an item, the application needs to get handle of item stream via OmmConsumerEvent,handle() in onRefreshMsg(), and then use the handle in the OmmConsumer.unregister() method.

    public void onRefreshMsg(RefreshMsg refreshMsg, OmmConsumerEvent event)
    {
        System.out.println("Handle: " + event.handle());
        System.out.println("Item Name: " + (refreshMsg.hasName() ? refreshMsg.name() : "<not set>"));

Sample output

Handle: 2
Item Name: TRI.N
Service Name: XXX
Item State: Open / Ok / None / 'All is well'
Fid: 1 Name = PROD_PERM DataType: UInt Value: 6562
Fid: 2 Name = RDNDISPLAY DataType: UInt Value: 64
...
Handle: 3
Item Name: IBM.N
Service Name: XXX
Item State: Open / Ok / None / 'All is well'
Fid: 1 Name = PROD_PERM DataType: UInt Value: 62
Fid: 2 Name = RDNDISPLAY DataType: UInt Value: 64

loy.longyi

Pimchaya.Wongrukun

Thank you for your reply!

Per ur suggestion, I can create a new batch request and call registerClient(..) to subscribe new RICs, and ignore the ones which I don't need.

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