GenXDM (formerly gXML) provides an XDM XQuery/XPath Data Model applications programming interface for Java. It makes extensive use of Java generics to enable the API to run over any arbitrary tree model for which a "bridge" has been created—thus the name: GenXDM. Bridges are provided for W3C DOM, for Apache Axiom, and for a simple "reference model" intended to aid others to develop bridges as well.
The API divides naturally into "bridges" and "processors." A bridge exposes an instance of the Data Model (typed or untyped, mutable or immutable). A processor operates over the data model—several examples are provided with interesting functionality, core utility, or as samples for the inspiration of further development.
GenXDM is designed to allow the current (very broad and deep) infrastructure of XML tools to continue working, using their preferred form of model for XML, while providing a path forward in which new tools can be model-agnostic. That is, it's well-known by now that one cannot introduce a new tree model for XML and expect to see it supplant the DOM. We don't try to do so. We provide an API against which tools can be built—and that API is more pleasant and more predictable to work with than the DOM. We also provide a "bridge" to the DOM (which is not a "wrapper," but uses the Handle/Body pattern to introduce absolute minimal overhead). That, in turn, means that other XML tree model APIs can be used as well, so long as there's a bridge for them.
Projects often enough do this themselves—typically using a wrapper pattern rather than a bridge pattern, and typically as a side effort, rather than as the primary goal. The result is extra overhead (wrapper, or Facade, is not an effective pattern when dealing with very large XML documents) and ultimately a loss of momentum. In most cases, different 'supported' tree models have different support profiles, different levels of completeness (and eventually, the whole attempt to be more generic is abandoned: "Everybody uses DOM").
If you'd like to use it in a maven build environment, add this repository: [http://www.genxdm.org/maven2/])http://www.genxdm.org/maven2/)
Note: that repository is no longer available.