Finding the Compromise – the Adapter Framework - Applied SOA Patterns on the Oracle Platform - page 371

• And finally, Protocol Bridging on OSB will be simply inevitable if we have ser-
vices in our inventory communicating synchronously and asynchronously (via
queues). In this case, the most logical approach is to establish OSB Service
Broker as we did in Chapter 4 , From Traditional Integration to Composition -
Enterprise Business Services with some Adapter framework around it.
Tip
For the SOA exam preparation (S.90.xx), please keep in mind that Data Format
Transformation, Data Model Transformation, and Protocol Bridging SOA pat-
terns are the parts of Service Broker compound patterns, which is an essential part
of ESB implementation. You also should remember that you can apply any of
these patterns at any layer of your SOA infrastructure, but necessity of this ap-
plication signifies that your design is not really optimal.
We can come to a conclusion that after a quick walk-through of these of these use cases
(five in total) described previously. We can clearly see that Protocol Bridging pattern will
be highly demanded only in one of them. With the implementation of the Canonical
Schema SOA pattern, Data Model Transformation can be avoided and Data Format Trans-
formation can be solved on the service side. All of this will minimize our integration ef-
forts and help establish a more predictable and reliable Service Inventory, well suited for
long- and short-running compositions.
How can you achieve this? Sorry, the answer is quite non-technical and has only one
word—Governance. You, as an architect, are the Mayor of this SOA metropolis and it's
you who is responsible for establishing policies and watchdogs around the crucial ele-
ments of your SOA infrastructure and in context of the Adapter framework— the Feder-
ated Endpoint Layer. This compound pattern is a result of the combination of the follow-
ing patterns, which we discussed earlier:
• Canonical Protocol : Clearly, it's impossible to have only one protocol (transport
and messaging) in our Service Inventory. From the previous use cases, you can
expect that at least three will be required. Direct binding can be achieved through
configuration and will not require (significant) efforts for bridging. Watch for oth-
ers two and do not let them spread around. You can mitigate the risks by promot-
ing the Service Facade and Concurrent Contracts at earlier stages of the service
design.
• Canonical Schema : Establish the EBO model and EBM schemas as your first
step. Stay alert about any amendments in XSDs.