In this example a Memo input is sent to the orchestration.
The Memo message is of two kinds, "Memo.xml" and an "EndMemo.xml"
(Flag is set to STOP).
NOTE: The EndMemo signifies the end-of-batch signal.
1.
When the first Memo arrives at the receive location, a new instance of
the Orchestration is created with the Correlation Set as the Receive Port name.
2.
All other messages which arrive at the same Receive port would have the
same Correlation set and would use the same instance of the Orchestration.
3.
When an "EndMemo.xml" arrives into the Orchestration an
exception is thrown by the orchestration and the Orchestration state becomes
“Suspended (non-resumable).” All other messages which arrive after the “EndMemo.xml”
will not be processed. When this Orchestration instance is terminated it gets
into “Completed with Discarded Messages” state. In this case the Orchestration
needs to be terminated. The entire set of messages which were not processed in
this case needs to be resubmitted again.
4.
The Logic has to be written in such a way so as to Terminate the
Orchestration in the case where a EndMemo arrives.
5.
After the “Suspended Orchestration” is terminated, a new instance of the
Orchestration is created once a message arrives at the receive location. This
Orchestration will continue to process new messages placed at the receive
location until an EndMemo.xml arrives, which again suspends the orchestration.
6.
Thus, in the case of a “Singleton Orchestration” a suspended
non-resumable Orchestration needs to be terminated, in order to process all the
backlog messages. The messages which were not processed also need to be
resubmitted again.
Quick Summary: A memo message
arrives at the receive location, which creates an instance of the
orchestration. The second receive shape picks up the rest of the messages from
the receive location, using the same orchestration instance created.
Figure 2 - Orchestration Screen Shot
Quick Takeaways
·
Observe that the same logical Receive Port is used for both the
Receive shapes.
·
Observe the while LOOP which looks for the flag in the messages
and terminates the Orchestration once an End Memo is received.
·
The use of Correlation type enables a Singleton Orchestration
which requires a property or a set of properties to be common across a set a
messages.
