Event handling data flow

When the adapter acts as a DTS responder, data flow occurs as follows:

  1. The request message is received by the adapter.
  2. A business object is constructed by the adapter and sent to the broker.
  3. A reply is sent back to the adapter.
  4. The reply is sent to VME via VJC as one or more messages.

On initialization, the adapter checks for the value set for the configuration property ResponderConnectionsPerService, and it opens that number of responder connctions per configured service. When event polling occurs, the adapter requests a message on each connection where a message may be waiting.

The DTS protocol requires that the size of the request from the VJC is only one message. If the request consists of more than one message, the request is discarded. Reply messages, received from the broker, must be contained in a single business object. If the reply message in the reply business object is greater than the size specified in the MaxMessageDataSize configuration property, the adapter will break it into appropriate size messages and each message will be sent to the VJC. The connector configuration property ReplyTimeout determines how long to keep a VJC connection for a particular conversation open while waiting for a response. When this time has elapsed, the conversation is terminated and the connection is made available. If a response is received after termination, it is discarded and an exception is thrown. Additionally, the adapter will take the value specified in the ReplyMessageTag attribute of the business object, and set the MessageTag of the DTS message to that value before sending the message to the VJC.

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