Events in ADF BC and handled by the Soa Suite Mediator

You may already know that events plays an important role in Soa Suite 11g. In this blog entry I will show how you can raise events in your ADF JSF application with ADF BC ( BC4J). These events can be intercepted by a mediator of soa suite 11g and this mediator can start other processes. In my case I publish these events to a file. I hope with this blog you get an inside look how events works.
The first step is to configure the entity in BC4J for events. In this example I use the customer table of the oe schema. On this entity I add a CreditLimit event which fires for every customer insert or update. To this event I add two customers attributes, The customerId and the creditlimit( BC4J adds automatically the old and new value of these attribute ).
BC4J generates a edl and a schema file. Here are an example of the generated files

<?xml version = '1.0' encoding = 'UTF-8'?>
<definitions 
targetNamespace="/nl/ordina/events/model/businessobjects/events/edl/Customers" 
xmlns:ns0="/nl/ordina/events/model/businessobjects/events/schema/Customers" 
xmlns="http://schemas.oracle.com/events/edl">
   <schema-import 
     namespace="/nl/ordina/events/model/businessobjects/events/schema/Customers" 
     location="Customers.xsd"/>
   <event-definition name="CreditLimit">
      <content element="ns0:CreditLimitInfo"/>
   </event-definition>
</definitions>

The customer schema

<?xml version = '1.0' encoding = 'UTF-8'?>
<xs:schema 
   targetNamespace="/nl/ordina/events/model/businessobjects/events/schema/Customers" 
   xmlns="/nl/ordina/events/model/businessobjects/events/schema/Customers" 
   elementFormDefault="qualified" 
   attributeFormDefault="unqualified" 
   xmlns:xs="http://www.w3.org/2001/XMLSchema">
   <xs:element name="CreditLimitInfo">
      <xs:complexType>
         <xs:sequence>
            <xs:element name="CustomerId" type="DecimalValuePair" minOccurs="1"/>
            <xs:element name="CreditLimit" type="DecimalValuePair" minOccurs="1"/>
         </xs:sequence>
      </xs:complexType>
   </xs:element>
   <xs:complexType name="ValuePair" abstract="true"/>
   <xs:complexType name="DecimalValuePair">
      <xs:complexContent>
         <xs:extension base="ValuePair">
            <xs:sequence>
               <xs:element name="newValue" minOccurs="0">
                  <xs:complexType>
                     <xs:complexContent>
                        <xs:extension base="xs:anyType">
                           <xs:attribute name="value" type="xs:decimal"/>
                        </xs:extension>
                     </xs:complexContent>
                  </xs:complexType>
               </xs:element>
               <xs:element name="oldValue" minOccurs="0">
                  <xs:complexType>
                     <xs:complexContent>
                        <xs:extension base="xs:anyType">
                           <xs:attribute name="value" type="xs:decimal"/>
                        </xs:extension>
                     </xs:complexContent>
                  </xs:complexType>
               </xs:element>
            </xs:sequence>
         </xs:extension>
      </xs:complexContent>
   </xs:complexType>
</xs:schema>

Let's make a JSF page on this entity and publish this application to the Soa suite server. If you don't do this I don't believe the events will be intercepted by the mediator.
Now we have to patch two procedures in the soasuite schema ( JDev TP4). The first procedure is edn_dequeue_bus_event, we have to change the schema name with your own soasuite schema do this before the queue name DBMS_AQ.dequeue(queue_name=>'xxxxx.edn_event_queue'. The same but now for procedure edn_enqueue_business_event DBMS_AQ.enqueue(queue_name=>'xxxxx.edn_event_queue'
The events are enqueued in the following queue edn_event_queue. This queue is located in your own soasuite schema. The published event looks like this.

<business-event 
   xmlns:ns="/nl/ordina/events/model/businessobjects/events/edl/Customers" 
   xmlns="http://oracle.com/fabric/businessEvent">
   <name>ns:CreditLimit</name>
   <id>30b14edf-f366-4091-97e8-3b6a2d514116</id>
   <content>
      <CreditLimitInfo xmlns="/nl/ordina/events/model/businessobjects/events/schema/Customers">
         <CustomerId>
            <oldValue value="148"/>
            <newValue value="148"/>
         </CustomerId>
         <CreditLimit>
            <oldValue value="1700"/>
            <newValue value="1100"/>
         </CreditLimit>
      </CreditLimitInfo>
   </content>
</business-event>

If I manually dequeue this queue the result looks like this.

We are ready with ADF and now we can go to the soa suite part. We create a new soa suite project where we add a mediator. Select now the Subscribe to events template. and browse to the customer.edl which is located in the bc4j model project.

In my case I add a file adapter and connect this file adapter to the mediator.

The last step is to make a stylesheet mapping between the mediator and the file adapter.

The events are now stored in a file. I hope you got a good impression how it works. In the next blogs I will continu this story by adding the CEP soa suite component and BAM j2ee edition to this example