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Java RFA API connection event

We are connecting to TREP via a JAVA RFA API, once connected we will subscribe to RIC updates for a large set of RICs.


Q1. There is a connection Event we can use to determine the status of the connection.

Can you please explain some of the circumstances in Reuters which would lead to these connection events?

For example at the close of Market do you send a down?

Q2. Do Reuters provide information as to when the RIC is not being updated (data is stale)? Can we use the Quality of Service field to check this?

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Hello @mukund.patel

Regarding the question 1, the Connection Event represents information of "a connection between API and its peer" only. For the consumer application, it will receives Connection Event when the RSSL connection with TREP/OMM Provider is UP or Down (disconnect).

Please see more detail regarding the Connection Event in section 8.6.1 of RFA Java Development Guide.

The market close does not makes the API sends connection event state DOWN to the application. If there is no update in Elektron, the application will not receive update messages from the API.

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Hello @mukund.patel

For question 2, you can use the OMMState information in the Update/Status Response message to verify the health status of the data.

  • OMMState.Data: Conveys data about the health of data flowing within a stream
  • OMMState.Steam: Conveys data about the stream’s health
  • OMMState.Code: An enumerated code value that conveys additional information about the current state.
  • OMMState.text: Specific text pertaining to the current data and stream state

Example: If the application receives OMMState “Stream.OPEN, Data.SUSPECT” from the API, it means the data is unavailable or unknown (STALE) but the item stream is still opening.

Please see more detail regarding the OMMState in section 10.3.6 of RFA Java Development Guide.

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Thanks @Wasin Waeosri

2 follow up questions on the same subject

If the OMMState.data = SUSPECT it seems to imply STALE. Is this something that Reuters calculate or is this something that the Broker/Exchange has decided to tag their data with?

Does the OMMState.data = NO_CHANGE mean that the data is valid but has not changed. If so is this something that the Broker/Exchange has decided to tag their data with?

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Hello @mukund.patel

  • The STALE can be occurred from various reasons such as a subscription service is down, the Data feed was down, the upstream TREP components were encountered the problem, disconnection between API and TREP, etc.
  • Data State “NO_CHANGE” indicates that there is no change in the state of the data, used to provide additional information related to the status of a data stream. This means when the application receives a message with the data state NO_CHANGE, it indicates that there is no change from the previous data state; the previous state could be OK or Suspect.

Please note that the API does not know any information about the Broker or Exchange of that publishes data, it just receive a message (Refresh, Update, Status) from TREP/Elektron and pass it to application "as is".

Please also note that the API handles the STALE (Stream “Open” and Data “Suspect”) scenario automatically and the application does not need to handle this by itself. Once the connection is re-established or the service becomes UP, the application will automatically continue to receive the subscribed data as normal.

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