We present our experiences with XML technologies in a series of Internet and Intranet e-Sales projects we realized for ALSTOM Power (Switzerland) Ltd.

Our experiences show that XML can be successfully applied in many different contexts. We mainly differentiate between document- and data-centric contexts, but there are others, and we also distinguish between applying XML technologies in our development process versus using XML in the delivered products.

We believe that XML has some basic characteristics that go well with established software engineering principles, and provides advantages in the areas of maintenance, data storage, standardization, independence, reuse, complexity, costs, and availability.

The learning curve is quite steep but gentle. It is possible to become productive in a short amount of time. Our whole team of software and aerodynamics engineers has quickly learnt and embraced the new technologies. Java and XML complement each other very well, which is also due to the excellent tools provided by the Apache Jakarta project, which are open source and freely available. Other open source and commercial tools fill the gaps, notably in the area of entering and editing XML documents, creating XML schemas, and creating XML XSLT scripts.

Using XML technologies in a pervasive way throughout a software system allows to leverage this investment in tools, training and experience.

While using XML pervasively we believe that from a software architecture view point only isolated parts and layers of our software architecture should be exposed to the XML technology, to make the system more stable and easier to maintain, modify, and extend.

In the paper we first cover general characteristics and advantages of XML as we perceive them.

Next we present examples of using XML in different contexts in our projects, such as: pdf document generation using XSLT, XSL:FO, and FOP; dynamic images using SVG; dynamic web page content generation using XSLT; java object persistence using SAX and DOM and XML files in the file system; data storage using SAX and DOM and XML files in the file system; application configuration using SAX and DOM and XML files in the file system; remote and cross-platform process execution using SOAP; build and packaging control using jakarta-ant, and managing the requirements engineering process using pdf document generation

For each application we give an example of how we used XML and which XML technologies were applied. We try to point out alternative approaches and show advantages and limitations we found in our approach. We conclude with lessons learnt and what to avoid and give pointers to related work.