How to fetch multiple Symbols data by making one call for EMA?(Ex : Sym1,Sym2,Sym3....)is it corr...

How to fetch multiple Symbols data by making one call for EMA?(Ex : Sym1,Sym2,Sym3....)is it correct way: consumer.registerClient(reqMsg.serviceName("ABC").name("Sym1,Sym2,Sym3"), appClient);?

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Accepted answers

pimchaya.wongrukun01

Hello @priyanka.mundargi

An EMA consumer application can request multiple items using a single request called a batch
request. After the consumer sends an batch request to the
ADS, the ADS responds by sending the items as if they were opened individually
so the items can be managed individually as shown in the figure below:

Hence, your EMA application just once calls OmmConsumer.registerClient(..) specifying array of multiple Symbols.

A snipped
source code in EMA Java:

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);

For the complete application source code shipped with Elektron Java SDK package, it is <Elektron Java SDK
package>\Ema\Src\examples\java\com\thomsonreuters\ema\examples\training\consumer\series300\example370__MarketPrice__Batch.

A snipped
source code in EMA C++:

UInt64 handle = consumer.registerClient( ReqMsg().serviceName( "DIRECT_FEED" ).payload( ElementList().addArray( ENAME_BATCH_ITEM_LIST, OmmArray().addAscii( "TRI.N" ).addAscii( "IBM.N" ).complete() ).complete() ), client );

For the complete application source code shipped with Elektron C++ SDK package, it is

<Elektron C++ SDK
package>\Ema\Examples\Training\Consumer\300_Series_Examples\370__MarketPrice__Batch

All comments

Nipat Kunvutipongsak

@priyanka.mundargi, EMA doesn't support that comma separated items because OMMConsumer threats a name value of a ReqMsg object as an individual single item. So, you should use a loop to help explicitly iterate calling the registerClient() method for each item.

For example:

// Single item call
ReqMsg reqMsg = EmaFactory.createReqMsg();
consumer.registerClient(reqMsg.domainType(EmaRdm.MMT_MARKET_PRICE).serviceName("DIRECT_FEED").name("JPY="), client);

// Multiple items call
String[] items = {"JPY=", "THB=", "EUR="};

ReqMsg reqMsg = EmaFactory.createReqMsg();
for (String item:items) {
    consumer.registerClient(reqMsg.clear().reqMsg.domainType(EmaRdm.MMT_MARKET_PRICE).serviceName("DIRECT_FEED").name(item), client);
}

Hope this helps.

pimchaya.wongrukun01

Hello @priyanka.mundargi

Hence, your EMA application just once calls OmmConsumer.registerClient(..) specifying array of multiple Symbols.

A snipped
source code in EMA Java:

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);

A snipped
source code in EMA C++:

UInt64 handle = consumer.registerClient( ReqMsg().serviceName( "DIRECT_FEED" ).payload( ElementList().addArray( ENAME_BATCH_ITEM_LIST, OmmArray().addAscii( "TRI.N" ).addAscii( "IBM.N" ).complete() ).complete() ), client );

For the complete application source code shipped with Elektron C++ SDK package, it is

<Elektron C++ SDK
package>\Ema\Examples\Training\Consumer\300_Series_Examples\370__MarketPrice__Batch

priyanka.mundargi

Am getting below in logs "state="Closed / Suspect / None / 'Login stream was closed.'

What if i need continous data?

priyanka.mundargi

Why are we reading Symbol as Ascii?is it always ascii?using array.add(EmaFactory.createOmmArrayEntry().ascii("TRI.N"));

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