Serialize/Deserialize messages in OmmConsumerClient

david.ainsworth · January 2020

Hi,

I am using the Java EMA library (https://github.com/Refinitiv/Elektron-SDK/tree/master/Java/Ema) and consuming messages by implementing an OmmConsumerClient.

We want to forward the messages onto our downstream clients but also to persist the raw messages in a file so that they can be decoded later for debugging.

Is it possible to serialise/deserialise these messages (RefreshMsg/UpdateMsg etc)?

Thanks

umer.nalla · January 2020

Hi @david.ainsworth

First thing to note is that for exchange fee liable data you cannot redistribute the data to downstream subscribers without potentially breaching data usage licenses. Please check with your Refinitiv account representative before proceeding.

From a technical aspect, you can clone the incoming message by using EmaFactory.createRefreshMsg(msg), createUpdateMsg(msg) etc. Once you have the cloned copy you can manipulate the msg, e.g. pass it off to another thread for parsing etc. See the EMA Java Reference Manual for further details.

Also, not sure if this is what you had in mind in terms of debugging, but you can enable XmlTraceToStdout and redirect that. The XMLTrace output contains all msg sent and received by the API to the server. You can then refer to the XML for debugging purposes.

david.ainsworth · January 2020

https://community.developers.refinitiv.com/discussion/comment/54413#Comment_54413

Hi Umer,

Thanks for the response

It's not cloning that I want to do specifically, it's to serialise the message to raw bytes to a file which we can then read back in later and deserialise to a message

umer.nalla · January 2020

https://community.developers.refinitiv.com/discussion/comment/54414#Comment_54414

Hi @david.ainsworth

I have not tried this, but their is a asHex() method on the Refresh or Update Msg which returns a ByteBuffer - the only thing I can thing of at this time for accessing the underlying content of the messages. However, cant immediately think of how you to deserialise it later.
Since the ElektronSDK is open source and we provide the source, you may be able to modify it achieve whatever it is you have in mind...

If, however, your main objective is to capture and play back data, then you can use our test tools which allow this - see the article Recording and Playback of Elektron Data