Database Reference
In-Depth Information
Summary
Oracle realization of the Service Bus is based on the Business Service / Proxy Service
concept, where every service is treated individually. That's what you will learn in every
topic dedicated to OSB (such as
Oracle Service Bus 11g Development Cookbook
,
Guido
Schmutz and Mischa Kölliker
,
Packt Publishing
). This kind of personal-touch approach for
every service has a strong reason as we would like to maintain the highest performance
possible and desirable level of modularity. Only one more or less complex pattern (refer to
the second figure in the
Implementing a basic proxy on OSB
section) is really provided out
of the box in OSB: Split-Join. Using this pattern, we can split a really big message that has
clearly distinctive separate parts (such as order line in a big order), do the parallel calls to
order the line processor, gather responses in a join phase, and deliver the processed pay-
load.
You have to implement all other SOA patterns yourself, just like we have covered in this
chapter:
• Message Enrichment (Callout action); it's not a decorator though as we are not
adding new features to our contract.
• Static Routing (Static Routing table).
• Dynamic Routing (Dynamic routing action, XQuery as a possible destination).
• Transformation (partial or complete) using XQuery or XSLT. Remember, XQuery
is more complex than XSLT in general and not an XML. You do not have nice
graphical features for elements mapping, but you have much more flexibility there.
All of these implementations are not a problem as OSB has a lot of features to support your
development. The challenge will become apparent when you have hundreds (and most
probably thousands) of synchronous services you will have to decouple, interconnect, del-
egate, and route.
For the services with similar operations or similar compositions, Agnostic Controller will
help you minimize the number of atomic proxies that will turn your state-of-art ESB into
spaghetti-mess if developed in an uncontrollable manner. We believe that the way of estab-
lishing agnostic Service Broker with Dynamic Intermediate Routing presented here will
save you from lots of headache. Not all features and components of the actual solution
were presented. We omitted inbound and outbound Service Facades, holding features that
are specific for Northbound and Southbound parts of OSB, but it was our intention (refer to
the table in the
Detailed analysis - functional decomposition
section) to concentrate on
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