With the introduction of Integrated SOA Gateway, there are plenty of new SOA related features in R12.1 version. In this article we will see a video demo of the wizard for invoking webservices via Business Event. In R12.1 you can create a subscription of type "Invoke Web Service". Once you select this subscription, you are then prompted to enter the WSDL of the webservice that must be invoked in response to the business event. This initiates a Web Service subscription wizard in R12.1. These steps are shown in the video link below




How does the business event subscription wizard work?
This wizard parses the WSDL that you are attaching in subscription and then prompts you through a series of questions to select the Method that must be called from Web Service.




How does the webservice get invoked?
The Java WSIF [Web Service Invocation Framework] is used to invoke the desired web service dynamically.




What is WSIF?
Usually, when you wish to invoke a method within the Web Service WSDL, you generate the stubs which act like a "local proxy" for the web service. Using WSIF, the Webservice can be dynamically be geneated. The Business Event Subscription in this case invokes a class named oracle.apps.fnd.wf.bes.WebServiceInvokerSubscription. This class internally reads the definition of the subscription and invokes the Web Service.




What if I want to do additional processing before/after Web Service Invocation via Business Event?
When the business event subscription for Web Service fires, then WebServiceInvokerSubscription.onBusinessEvent() is executed. To do further processing, follow the steps below
1. Extend class WebServiceInvokerSubscription
2. Override methods onBusinessEvent(),preInvokeService(), invokeService()and postInvokeService() as required
3. Place the java class name of extended class in field "Java Rule Function" in Business Event Subscription

Click here to see the video demo of attaching webservice to Business Event Subscription via wizard

How do I process the response of the webervice?
There are two options for you.
Option 1. Use extended class based on WebServiceInvokerSubscription and override the methods to trap the response and process it.
Option 2. Attach the following parameters to the business event subscription
    WFBES_CALLBACK_EVENT
    WFBES_CALLBACK_AGENT
These parameters dictate the name of the business event that will be raised in response to the WebService return message.

Click here to see the video demo of processing response of WebService

One note- I haven't tested this functionality all the way yet. My initial tests indicate that this feature is not 100% production ready yet because some of the legitimate webservices are not getting parsed by WSDL Subscription wizard. The webservice example used in this article is the same as that in Metalink Note 741783.1. However the Metalink note uses the pre-R12.1 technique where wizard was not present.

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