Applied SOA: Service-Oriented Architecture and Design Strategies

CHAPTER 5

Service Context and Common Semantics

SOA is useless without good data.

– Joe McIndrick

Chapter 4 showed how to use techniques of business process modeling and subject matter partitioning to identify business services that conform to a uniform business architecture. In this architecture, individual services do not exist in isolation — they should be usable in multiple contexts. In other words, these services should be interoperable. Uniform messaging semantics is one of the most important requirements for service interoperability. This ensures that service consumers and providers exchange data in a consistent way that enables their mutual understanding of the information they are intended to process.

This chapter starts by revisiting the importance of uniform messaging semantics and a semantic information model, and then introduces modeling techniques for creating that model based upon information modeling and object-oriented analysis principles. You learn how to synthesize a model by exposing details about a problem based upon the things in the domain. This technique has been shown, in practice, to provide a cohesive foundation for ensuring common semantics.

In constructing an information model, you learn how to model the world of a domain in terms of objects, attributes, and associations and extend these basics by using techniques of specialization and constraint modeling to achieve better model accuracy. We also show you how to partition large models, both to manage ...