Finding the Compromise – the Adapter Framework - Applied SOA Patterns on the Oracle Platform - page 414

8. Start OEPE and create a new OSB project and import JCA, XSD, and WSDL
files (right click on a project and select Import ) from the JDev project root. If the
JCA file will be invalid after import, just open it and fix the path according to the
new location.
9. Generate Business Service by a right-click from JCA. We will leave all generated
parameters for transport, message handling, and policy as is.
10. Now we need to create proxy service in order to complete the decoupling. We
already have WSDL from the SCA DB adapter, but we really would like to hide
the DB-related implementation and present the true decoupling.
11. Start Proxy Service wizard and give it a suitable name. Add Routing node and
browse to the Business Service created earlier, similar to the previous example.
12. By changing the ExecutionPlanLookup service from a File-based to DB-based
implementation, we have created a complex view for consolidation of all relevant
service metadata, stored in the Enterprise Service Repository ( ESR ) into com-
plete Execution Plan ( EP ). As the ExecutionPlanLookup service is the utility
service, we can add an adapter into composition without compromising SOA
principles. We also preserved the file-based implementation (together with the
Oracle Rule Engine EP's resolution) and can switch between File-based and DB-
based implementations using configuration settings or the MH parameter (tracing
level element). View, Query, and In/Out Transformations on Adapter are quite
heavy (although not complex), so we will skip the detailed implementation and
trust that you can implement it yourself, using the presented taxonomy and DB
schema, if it will suit your needs. The point here is should we move the Trans-
formations into OSB, leaving Adapter as a bare DB access point or keep trans-
formations to the canonical EP (or any other Canonical Message in your case) in-
side adapter? Actually, we answered this question earlier, but let's look at the
technical possibilities.
13. While working with OSB, you must have definitely noticed two things. Despite
the wide range of message manipulation techniques, XQuery is the most com-
mon, and secondly, XQuery mapper is rather minimalistic compared to the XSLT
mapper in JDeveloper. Still, this mapper is quite capable of doing the quite com-
plex operations and you can access it in OEPE by navigating to Window | Open
Perspective | XQuery Transformation . In the following screenshot, you can see
the actual EP mapping example that we used in the Synchronous Service Broker
realization (on OSB) to create simple task collection: