Excel is arguably the most used format for documentation by businesses organizations. One can speculate why that is the case: loosely-structured text format, tendency of people to think of complex data sets in table format, available on almost every desktop.  While most of us can think of better ways to capture and manage business data, the fact remains, Excel is here to stay and a lot of information used in IT projects is in that format. This article is about my experience in processing Excel files using Java.

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XML is the common data format in the exchanges between Business and Operations Support Systems (B/OSS). The exchanges carry  business objects (BO) which are identified by one of more member elements. This article is about how to declare and use object keys in XMLs in the context of an Enterprise Information System (EIS).

The key or identity information of a XML business object (XML-BO) is a "metadata" aspect: it is not explicit in the XML, instead  is defined separately, as meta-data,  known by the components that process the data. XML meta-data can be described in multiple  ways. The one that I will use in this article, and the most common, is the XML Schema Definition (XSD).

XSD does not directly support the concept of object ID but has related constructs. One of them is the ability to declare element identity constraints using the XSD elements: ID/IDREF/IDREFS and KEY/KEYREF. These constructs are used to impose uniqueness and/or referential integrity within an instance of XML. They are not intended as having a cross-instances meaning. But maybe, extending the semantic, we can use these constructs to define object identity in an EIS context.

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UML is a well-established notation for the design of object-oriented applications. In component detailed design meetings people are comfortable describing a design and articulating issues using UML.  This is not the case in integration projects. I go in the meetings to review an integration solution and invariably the discussion is based on a Power Point presentation with diagrams that include very basic, ad-hoc notations. The picture on the right is an example; the diagram mixes the component model with the deployment model, using ad-hoc notations for the components and execution environments.

Why is that? Why UML is not used more often in integration projects?

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From time to time I read about an interesting Java project and would like to try it.  For example Apache Jackrabbit, a library implementing JSR 170 (Java Content Repository). But setting up the my Java environment to run the examples is a hassle because of the many libraries required. Over time I got better at starting new projects: I have project snapshots that contain all the Eclipse and Ant artifacts for a simple application with proper JUnit tests and logging. Still, downloading all required libraries in the proper directories and updating Ant and Eclipse configuration is a drag. There must be a better way to do it other than downloading manually libraries from various sites. In this context I decided to try  Apache Ivy with the recently released version 2.0.0.

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