Getting an ad-hoc RefreshMsg while stream is open

paz.barda

TLDR - java consumer app, trying to find the best way to get on-demand/adhoc RefreshMsg for couple of K RICS every few minutes.

Hi,

We're developing a java consumer application. one of the requirements is to make sure that for every RIC we're tracking (~10K), our data is no older than X minutes. this means that for every RIC that did not get UpdateMsg within the past X minutes, we'd like to get an on-demand/adhoc RefreshMsg.

what would be the best way (=cleanest and most efficient) to initiate a RefreshMsg on an already-open stream?

app-specific details:

> pom:

<dependency>
    <groupId>com.thomsonreuters.ema</groupId>
    <artifactId>ema</artifactId>
    <version>3.4.0.0</version>
</dependency>

> our registration to OmmConsumer is based on View (we are interested in only ~20 fids):

private ReqMsg getViewReqMsg(String symbol) {
    OmmArray fidsArray = EmaFactory.createOmmArray();
    supportedFIDs.forEach(fid -> fidsArray.add(EmaFactory.createOmmArrayEntry().intValue(fid)));
    ElementList viewElementList = EmaFactory.createElementList();
    viewElementList.add(EmaFactory.createElementEntry().uintValue(EmaRdm.ENAME_VIEW_TYPE, 1));
    viewElementList.add(EmaFactory.createElementEntry().array(EmaRdm.ENAME_VIEW_DATA, fidsArray));
    return EmaFactory.createReqMsg()
            .name(symbol)
            .serviceName(service)
            .payload(viewElementList);
}

> this is how we are registering to each symbol initially:

private void registerAllSymbols(OmmConsumer consumer) {
    symbols.forEach(symbol -> {
        ReqMsg reqMsg = getViewReqMsg(symbol);
        symbolNameToLoginHandle.put(symbol, consumer.registerClient(reqMsg, appClient));
    });
}

> now, when acting upon an 'expired' RIC, this is what we've tried:

Option A: reissue

private Consumer<F> getExpiredSymbolStateHandler(OmmConsumer consumer) {
        return expiredSymbolState -> {
            String symbolName = expiredSymbolState.getSymbolName();
            ReqMsg reqMsg = getViewReqMsg(symbolName);
            consumer.reissue(reqMsg, symbolNameToLoginHandle.get(symbolName));
        };
    }

for some reason, this does not seem to have any effect (we're not getting RefreshMsgs, although UpdateMsgs are received so we know the stream for that RIC is still alive).

Option B: (re)register

private Consumer<F> getExpiredSymbolStateHandler(OmmConsumer consumer) {
        return expiredSymbolState -> {
            String symbolName = expiredSymbolState.getSymbolName();
            ReqMsg reqMsg = getViewReqMsg(symbolName);
            symbolNameToLoginHandle.put(symbolName, consumer.registerClient(reqMsg, appClient));
        };
    }

this seems to work fine whenever the ReqMsg is 'simple' (= no View is involved), but this means getting all fids, which is undesired. when doing the same with View (getViewReqMsg(String symbol) above) we start getting double messages, as if the 2nd register operation opened a new stream on top of the existing one (also undesired, of course)

Option C: unregister + (re)register --> BEST WE GOT SO FAR

private Consumer<F> getExpiredSymbolStateHandler(OmmConsumer consumer) {
        return expiredSymbolState -> {
            String symbolName = expiredSymbolState.getSymbolName();
            ReqMsg reqMsg = getViewReqMsg(symbolName);
            consumer.unregister(symbolNameToLoginHandle.get(symbolName));
            symbolNameToLoginHandle.put(symbolName, consumer.registerClient(reqMsg, appClient));
        };
    }

this works fine, but it feels like an overkill when doing it on several Ks of RICs every couple of minutes -- especially when there seem to be more natural options available in the API (like Option A).

obviously we're missing something with options A and B, any thoughts?

Thanks

Jirapongse

@paz.barda

Option A should be the optimal one to get the lastest refresh message.

From my testing, for reissuing with the same view, the view data can be ignored. Therefore, the code for reissue could be:

private Consumer<F> getExpiredSymbolStateHandler(OmmConsumer consumer) {
        return expiredSymbolState -> {
            String symbolName = expiredSymbolState.getSymbolName();
            ReqMsg reqMsg = getViewReissueReqMsg(symbolName);
            consumer.reissue(EmaFactory.createReqMsg(), symbolNameToLoginHandle.get(symbolName));
        };
    }