The adapter uses the Advanced event
processing interface to poll for events on the SAP server,
to process the events, and to send them to an endpoint.
The following list describes the sequence of processing
actions that result from an inbound request that uses the Advanced
event processing interface.
- A triggered event enters the event table with an initial status
of prequeued.
- When the adapter polls for events, the status of the event changes
from prequeued to queued if there are no database locks for the combination
of the user who created the event and the event key.
- After the event is retrieved from the event table, the status
of the event is updated to InProgress.
If locks exist, the status
of the event is set to locked and the event is requeued into the queue.
Every event with a prequeued or locked status is updated with every
poll. You can configure the polling frequency by using
the Poll Frequency property.
- After preprocessing all prequeued events, the adapter selects
the events.
The property Poll Quantity determines the maximum number
of events returned for a single poll call.
- For each event, the adapter uses the remote function specified
for the Retrieve operation to retrieve the data and send it to the
endpoint.
If the AssuredOnceDelivery property is set to true, an
XID value is set for each event in the event store. After each event
is picked up for processing, the XID value for that event is updated
in the event table.
If, before the event is delivered to the
endpoint, the SAP connection is lost or the application is stopped,
and the event is consequently not processed completely, the XID column
ensures that the event is reprocessed and sent to the endpoint. After
the SAP connection is reestablished or the adapter starts up again,
it first checks for events in the event table that have a value in
the XID column. It then processes these events first and then polls
the other events during the poll cycles.
- After each event is processed, it is updated or archived in the
SAP application.
When the event is processed successfully, it is
archived and then deleted from the event table.
The adapter
can also filter the events to be processed by business object type.
The filter is set in the Event Filter Type property. This property
has a comma-delimited list of business object types, and only the
types specified in the property are picked for processing. If no value
is specified for the property, no filter is applied and all the events
are picked up for processing.
For more information, see the following topics.