Some Nucleus components use XML files instead of Java properties files for configuration or other initialization tasks. Like properties files, several XML files of the same name can appear along the configuration path. At runtime, the Oracle ATG Web Commerce platform combines these files into a single composite file, which is then used by the appropriate component. This allows multiple applications or modules to layer on top of each other, forming a single definition file from multiple definition files.

This section describes the operations and rules that are used to combine two XML files into a new XML file. XML files are combined one tag at a time; in other words, tags are matched up, and the combination rules are applied to each pair of matched tags.

XML file combination is controlled by an XML attribute xml-combine. This attribute is used only in the preprocessing stage of XML file combination. Because the xml-combine attribute is not included in the file that results from the preprocessing combination of the XML files, it does not need to appear in the document type definition (DTD) for the XML files.