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Reviewer: Christoph F. Strnadl

While the idea of a service-oriented architecture (SOA) was conceived during the 1990s, the new paradigm of aligning an organization's enterprise information technology (IT) architecture with business needs has only recently gained enough momentum to attract widespread interest. This development has been and will be fueled to a large extent by the availability of accepted industry standards prompting vendors to furnish products and systems conforming to these standards and interoperating also in real-world deployment. However, information about these Web services (WS) standards is scattered and distributed in the relatively inaccessible standardization documents of different standardization bodies (such as the World Wide Web Consortium, the Organization for the Advancement of Structured Information Standards, and industry consortia). Moreover, they often also lack a coherent and consistent description of the "big picture," of the rationales behind a particular design choice within the isolated definitions in the standard's document. Furthermore, standards are continuously being updated and amended due to industry demand and implementation experiences. For enterprise architects, this evolutionary approach implies that documentation becomes outdated rather quickly, rendering books bought in 2002 or 2003 obsolete, for instance. If you have ever wanted to master the "big picture" of WS from a top-down IT perspective or needed to gain a broad and comprehensive technical understanding of relevant WS and related standards, this book is required reading. I was particularly grateful that the book does not limit itself to covering the usual suspects like Extensible Markup Language (XML), simple object access protocol (SOAP), Web services description language (WSDL), and universal description, discovery, and integration (UDDI) but also includes the various WS-* standards up to business process execution language (BPEL). Additionally, it describes two (almost) real-world examples where the composition of a WS application and the interplay of the various standards for a single mission are described. More specifically, it covers the following standards (in alphabetical order): BPEL; SOAP v1.2 (use of the name "simple object access protocol" has been deprecated); UDDI (universal description, discovery, and integration) v3.0; WS-Addressing; WS-Atomic Transactions; WS-Authorization; WS-Business Activity Framework; WS-Coordination; WSDL v1.1 and v2.0; WS-Federation; WS-Metadata Exchange; WS-Policy; WS-Privacy; WS-Reliable Messaging; WS-Secure Conversations; WS-Security; WS-Trust; XML (Extensible Markup Language); and XML Schemas. Some of this coverage is very brief, and for some broader topics, such as XML, the book is understandably restricted to the basics. The book is organized in nine parts that address logically related concepts, gently leading the reader from a motivational introduction (which also sets the ground for some basic concepts) toward the elaboration of the different standards, from fundamental building blocks to more advanced concepts, culminating in the presentation of two short (almost) real-world case studies. The elaborate index means the book is also a suitable source for quick references into the standards. Part 1 briefly introduces the concept of a service-oriented architecture (SOA) based on the accepted publish-find-bind (services) paradigm. In spite of the book's title, neither this part, nor any other section of the publication addresses hardware or specific software or includes actual programming code. Parts 2 and 3 focus on the basic ingredients of WS, namely SOAP, how to identify WS endpoints (WS-Addressing), and how to describe the externally visible properties and the internal implementation of WS using the WSDL including WS-Policy. Part 4 deals with the motivation and role of the UDDI standard for specifying a services repository and also provides a brief overview of WS-Metadata Exchange. Part 5 explains the basic roles of sequence and transaction in implementing reliable messaging and transaction processing and corresponding standards (WS-Coordination, WS-Atomic Transaction, and WS-Business Activity Framework). Part 6 addresses basic (WS-Security) and also advanced security issues in the context of WS like WS-Trust, WS-Secure Conversations, WS-Privacy, WS-Federation, and WS-Authorization. Modeling longer and more complex business interactions and processes is the subject of part 7 with the BPEL standard at center stage. In part 8, two (almost) real-life case studies display many of the concepts introduced earlier in a single and coherent context. In a business-to-business supply chain example, an auto dealer is able to access the car manufacturer's Web site to order and check certain auto parts. In the second business-to-consumer example, the WS application allows customers buying hardware to order specific additional service packages personalized to their needs and localized to their country. The book concludes with part 9, speculating briefly about related aggregation concepts stemming from IBM's Web Services Flow Language (WSFL), and the current and future direction of the standardization processes, which are clearly driven by industry. The book was written by a group of relatively well-known and respected authors who are directly or indirectly affiliated with IBM. The reader might want to bear this in mind, because on some occasions this bias becomes evident. For instance, only IBM's SOA platform is mentioned (as opposed to, say, Software AG's Enterprise Service Integrator); the authors limit their discussion of future concepts of WS aggregation to IBM's WSFL, ignoring the equally mighty business processes modeling language (BPML) by the Business Process Management Initiative (BPMI); and apart from public standards documents or Web sites, the book seems to cite primarily articles from IBM Systems Journal as opposed to other more neutral sources like IEEE Computer or Communications of the ACM . Apart from this (admittedly minor) criticism I can only fully agree with the high praise offered in the introduction: "Other books claim to present the complete Web services platform architecture, but this is the first one I've seen that really does." Online Computing Reviews Service