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In-Depth Information
Summary
We are in the middle of the topic, but journey is far from over yet. So far we covered the
three main SOA Frameworks: Service Collaboration (ESB), Service Orchestration (EBF),
and Application Business Connector Services (ABCS, or Adapters) and all SOA Patterns
associated with them. We also described the role of Enterprise Service Repository (yet an-
other framework, heart of the SOA Governance) in all of these frameworks. This chapter,
entirely dedicated to the ABCS layer had no purpose to cover all aspects of Adapters im-
plementation though, but rather how to optimize this layer in order to make all our service-
oriented applications in our inventory more intrinsicly interoperable (one of the major SOA
characteristics, you remember).
Why? Well, why does a classic construction brick have pretty much a standard size of 3
5/8". 2 1/4". 8"? Maybe because none of the construction architects in the entire world
want to have their masons waste their time adjusting boulders, rocks, and stones instead of
building houses and bridges? And further on, maybe that's the way the Pattern-based stand-
ardization approach, proposed by Christopher Alexander, becomes so increasingly success-
ful among the software architects as well?
The Extensive Adapter framework is not only a waste of time (and money) during design
time and development, but also the constant pain for Operations and Support depts and the
reason for more than 80 percent of outages and breakdowns in our operational environ-
ments. All middleware specialists know that they are the first people to blame when the
message from source A didn't reach destinations B and C. The root cause of
that—application A initially was not able to collaborate with applications B and C, and the
adapter was simply unable to fix this problem for a complete 100 percent. Even if it could,
it's an extra layer, adding complexity to our landscape and therefore making it susceptible
to faults.
Thus, our primary architectural task would be to make our core applications more service-
oriented for eliminating the requirements for adapters. This approach was demonstrated in
the first part of this chapter, when we optimized the OEBS APIs and Event Handling Sys-
tem for the Scandinavian Logistic operator. You were supplied with enough information
and code samples for your own implementation of this approach.
Composability and Composition Controllers are the primary goals of this topic as this prin-
ciple and these building blocks are endorsing reuse and modularity (read—cost savings and
operational reliability). Therefore, the second part of this chapter demonstrated how we
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