Modeling XML Applications with UML (Object Technology Series) [Paperback]

David Carlson's book covers a lot of material, including some background on each of the technologies, which helps to set the scene nicely.

The text is in three parts, dealing with "Foundations", "XML Vocabularies" and "Deployment" respectively. The overall themes are a fictitious B2B markup vocabulary and an example e-business portal using this. In general these served well as examples, but wouldn't be immediately relevant to the entire audience who could potentially benefit from the book.

I didn't find the use cases presented in part one very helpful, as they are little more than titles of use cases with general, high level discussion instead of having specific interaction steps. (It's possible that these use cases might provide a rough model for an e-business project similar to the example though.)

The second part of the book was more specific, and the text was mainly clear and readable. Unfortunately the important material towards the end on generating schemas left me rather unclear on what should be proper the treatment of UML associations. This was a shame, because the earlier chapter on linking makes it clear that this is a subject the author is something of an authority on. Using a simpler, restated UML model and presenting the schemas alongside a conformant XML instance document would have helped.

Part three gives a necessarily brief introduction to XSLT, and shows how it might be used for transforming vocabularies and for presentation. The final chapter reviews some of the newest aspects of e-business architecture.

What I hadn't appreciated, until I started reading this, is that the mapping from UML to XML is covered by an OMG specification for XML Metadata Interchange (XMI). The practical implications of this are well described in the book. The author's stated objective of imparting "actionable knowledge" is also achieved in large measure.

The book covers the full spectrum from Foundations to Deployment but its "tour-de-force" lies in its section on Vocabularies. As Schema modeling becomes more "object-oriented" with the introduction of XML Schema Recommendation, Dave Carlson describes a practical approach to modeling within the UML framework.

Proprietary graphical notations offered by specialist XML IDEs tend to present XML models in a "serialized" form, usually a tree structure. By using UML, the true nature of vocabularies - a network of containment, reference and inheritance relationships, can be viewed directly in a way that promotes comprehensibility, reuse and process integration.

In both concept and execution, the result is a very clean UML-XML mapping: well defined, clearly explained and solidly supported, by a running example. The accompanying website enables readers to consolidate their understanding by interacting with the example model and develop Schemas from their own UML models.

If you're involved in XML analysis/design and have access to UML tools, this book is essential. Standards bodies and tool vendors take note: Schema development should be done this way!