If you are using Xerces as your XML parser, you can have Xerces expand any XInclude directives.
The -xi option on the command line causes XInclude processing to be applied to all input
XML documents. This includes source documents, stylesheets, and schema documents listed on the command line, and
also those loaded indirectly for example by calls on the doc() function or by mechanisms such as
xsl:include and xs:include.
From the Java API, the equivalent is to call setXInclude() on the Configuration object,
or to set the attribute denoted by FeatureKeys.XINCLUDE to Boolean.TRUE on the
TransformerFactory.
XInclude processing can be requested at a per-document level by creating an AugmentedSource and calling
its setXIncludeAware() method. The corresponding method is also recognized on Saxon's implementation of the
JAXP DocumentBuilderFactory. When the doc() or document() or collection()
function is called from an XPath expression, XInclude processing can be enabled by including xinclude=yes
among the query parameters in the URI.
It is also possible to switch on XInclude processing (for all documents) by setting the system property:
-Dorg.apache.xerces.xni.parser.XMLParserConfiguration=
org.apache.xerces.parsers.XIncludeParserConfiguration
An alternative approach is to incorporate an XInclude processor as a SAX filter in the input pipeline. You can find a suitable SAX filter at http://xincluder.sourceforge.net/, and you can incorporate it into your application as described at Writing Input Filters.
On the .NET platform, there is a customized XmlReader that performs XInclude processing available at
http://www.xmlmvp.org/xinclude/index.html. You can supply
this as an argument to the method Build(XmlReader parser) in the DocumentBuilder class
of the .NET Saxon API.
For further information on using XInclude, see http://www.sagehill.net/docbookxsl/Xinclude.html