Create a new XML file called catalog.xml and save it into the {oXygen_installation_directory} / frameworks / sdf directory. The content of the file should be:
<?xml version="1.0"?>
<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog">
<system systemId="http://www.oxygenxml.com/SDF/abs.xsd"
uri="schema/abs.xsd"/>
<uri name="http://www.oxygenxml.com/SDF/abs.xsd"
uri="schema/abs.xsd"/>
</catalog>
To test the catalog settings, restart Oxygen XML Editor plugin and try to validate a new sample Simple Documentation Framework document. There should be no errors.
The sdf.xsd schema that validates the document refers the other file abs.xsd through an import element:
<xs:import namespace= "http://www.oxygenxml.com/sample/documentation/abstracts" schemaLocation="http://www.oxygenxml.com/SDF/abs.xsd"/>
The schemaLocation attribute references the abs.xsd file:
xsi:schemaLocation="http://www.oxygenxml.com/sample/documentation/abstracts
http://www.oxygenxml.com/SDF/abs.xsd"/>
The catalog mapping is:
http://www.oxygenxml.com/SDF/abs.xsd -> schema/abs.xsd
This means that all the references to http://www.oxygenxml.com/SDF/abs.xsd must be resolved to the abs.xsd file located in the schema directory. The URI element is used by URI resolvers, for example for resolving a URI reference used in an XSLT stylesheet.