Sunday, January 22, 2012

Understanding EAI Transaction Service

Recently I got the chance to work on a EAI requirement which requires the use of business service:  "EAI Transaction Service"

This post might help you if you are hearing this business service for the first time.

First of all, let me tell you what was the requirement for which I used this business service and later will tell you how it works.

We have integration between a third-party system which keeps the Quotes, created in Siebel. So whenever a Quote record is UPDATED, it should also get reflect in the third-party system. The synchronous transaction is being send via real-time Web Service call at the WriteRecord event of Quote BC. The requirement was, while sending the updated Quote XML to the other system, check for the web service response. If the response = "Success", it is fine, but if response = "Failed", then revert back the changes done by user on the UI. So lets suppose user has changed 3-4 fields on Quote list applet and saved the record, and while integration call, system receives the respone = "Failed", then system has to revert back the values of these 3-4 fields.

Now, let us see how EAI Transaction Service help in this scenario:

I will not discuss the integration details but just the technical details related to EAI Transaction Service. Please assume that we already have a function: "SendToInterface()" created which will take care of sending the Quote XML to the other system. Now, here is what you need to do:

1. BusComp Server Script -> General -> Declarations:

var svcEAITransService = TheApplication().GetService("EAI Transaction Service");
var psInp = TheApplication().NewPropertySet();
var psOut = TheApplication().NewPropertySet();

2. BusComp_PreWriteRecord:

function BusComp_PreWriteRecord ()
svcEAITransService.InvokeMethod("BeginTransaction", psInp, psOut);
return (ContinueOperation);

3. BusComp_WriteRecord()

var strResult = SendToInterface();
if (strResult == "Failed")
psInp.SetProperty("Is Abort", "True");
svcEAITransService.InvokeMethod("EndTransaction", psInp, psOut);

So, from the point you invoke "BeginTransaction" method, system keeps a check-point for you, till the time you invoke "EndTransaction" method. And as soon as EndTransaction get executed, the data gets commit actually to the database. 

Points to ponder:
  1. If BeginTransaction method has been executed, then execution of EndTransaction method is MUST for getting the data commit into the database. If for any reason, it not get executed or thin-client session get closed, data will never go to database.
  2. In the same session, the updated value is available for the Business Component and if you do a GetFieldValue in the current instance or try to fetch value via Integration Object, you will get the updated value.
  3. In case you have a Workflow Policy based on some field you have updated, it will only get trigger after the event of execution of method: EndTransaction.

Somebody might come back and ask why should even I use this business service, why don't I just call the "SendToInterface()" function in PreWriteRecord event itself and check for the web service response right there? If success, then let the WriteRecord event fire else prompt a message using RaiseErrorText?

Well, the above statement might sounds correct, but keep in mind EAI Siebel Adapter will run a separate query to fetch the data in SiebelMessage, so unless and until, the WriteRecord event fires (in the current session) it won't be able to get the updated values in SiebelMessage.

Hope this helps.