Building the Core – Enterprise Business Flows - Applied SOA Patterns on the Oracle Platform - page 214

The Rule Engine endpoint and decision service
In the third step depicted on the consolidated agnostic Composition Controller SCA dia-
gram, we called PlanLookupService to acquire the routing slip (EP). This service is
clearly visible among others in the list of target services that are available for invocation by
our Service Broker. You already know the basic structure of EP and the MessageHeader
elements used as input parameters; therefore, establishing WSDL for this service should
not be a problem. Simply put, this is all that we know: the requested product, county/affili-
ate, business event, and the requested business operation. This information should be suffi-
cient for determining which business process (in the form of EP) must be fired (namely,
EP's name extracted and passed for its execution in Business Delegate within a loop). Con-
sequently, these parameters will be the elements of the Business Rule components' inbound
and outbound variables, where outbound is just the name of an XML object (file) stored in
MDS.
To begin with, we design this SCA Composite in an exceedingly simple way; it should only
contain Mediator and the Business Rule component. We will start the configuration from
business rules. The configuration steps are obvious; just follow the Oracle documentation:
• The XSD schema will be created with two types, reflecting the inbound and out-
bound elements (hint: see the transformation part in the following screenshot). Feel
free to adapt the types according to your requirements or just simplify it, leaving
no more than three elements for the start.
• Drag the rules component from the right palette, and assign the input and output
variables from the defined XSD (input is based on the MessageHeader XSD
and output just on a string).
• These input and output variables will be our XSD-based rule facts.
• It would be useful to define baskets as List of Values ( LOV ) for country, affiliate,
product, and business operations (action types). Think of baskets as enumerators
with fixed values that we will use in our decision table.
Now, we can create our decision table as shown in the following screenshot: