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Keywords: Web services, SOAP, WSDL, REST Title: Understanding Enterprise SOA Authors: Eric Pulier and Hugh Taylor Publisher: Manning ISBN: 1932394591 Media: Book Verdict: Good overall view of SOA, but not at the nuts and bolts programming level

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Service Oriented Architectures (SOA) are where the big money is these days, with all of the major vendors tripping over themselves to prove just how service oriented they can make you if you hand over huge bundles of corporate cash. In fact in the race to win bullshit bingo it's hard to know what gets you the most points these days, a vendor inspired SOA white paper or a roomful of MBAs discussing business process management. Those at the development end of the food-chain might be wondering what it is that the SOA rush is all about. Is it really more than just exposing functionality as web services?

The authors of Understanding Enterprise SOA aim to cut through the hype and actually explain what SOA is about in words that are reasonably clear and easy to understand. Targeted at both 'business people' and 'technologists', the book is intended to provide a coherent picture of what SOA actually is, and, just as importantly, how this SOA vision can be realised in real life. Note, however, the use of the term 'technologists', it's a lot less specific than 'developers', but more of this later.

The opening chapter sets the scene and discusses the broader issue of enterprise architecture integration - in other words how to make different applications on different platforms work together. Problems of proprietary standards, vendor lock-in, tight coupling of interfaces and so on all lead naturally to a discussion of loose-coupling, open standards and XML as the lingua franca of the IT world. In the real world the most successful route to this is via web services and the triumvirate of SOAP, WSDL and UDDI. And that leads, finally, to an exposition of what SOA is all about: applications are assembled from functionality exposed as web services on different platforms.

This approach to enterprise software development obviously has enormous implications both in terms of integrating legacy applications and also in how new applications are constructed. According to SOA evangelists the days of massive monolithic applications are numbered, (though being a bit long in the tooth I'd wager that those days are numbered in the thousands…). Having spilled the beans and explained in reasonably plain English what SOA is really about, the authors then take the time to explore some of the broader technical and political issues that arise, from integrating enterprise applications to developing portals to security and change management.

On the whole the explanations are fairly clear, but there's a tendency to repetition in places; there are only so many times you can hear about the virtues of loose coupling before the thrill begins to pall. A running theme throughout the book is the experience of an imaginary corporation call Titan Insurance, the problems that this company is facing provides a useful framework to structure the book around and of course it helps to keep the focus on something concrete rather than lost in the light and fluffy world of MBA cloud diagrams.

For developers looking to get to grips with the nuts and bolts of SOAP, REST and the, er, rest, this isn't the place to look for details. This is decidedly not a book for those about to cut code. However, if you want to make sense of all of the SOA fuss and how it fits in with the web services you're crafting then this is definitely a good place to start.