Create and set up XML catalog files This article explains how to create and set up XML Catalog files. When Internet access is not available or the Internet connection is slow, the OASIS XML catalogs present in the list maintained in the XML Catalog Preferences panel (available from menu Options Preferences XML XML Catalog ) will be scanned trying to map a remote system ID or a URI reference pointing to a resource on a remote Web server to a local copy of the same resource. System ID references are mapped to local copies during document validation and when the content completion assistant computes the proposals presented in the content completion window. URI references are mapped to local copies during XSLT transformations and XQuery transformations. XML catalogs make documents machine independent so that they can be shared by many developers by modifying only the XML catalog mappings related to the shared documents. Any XML catalog that conforms to the OASIS XML Catalogs 1.1 Recommendation can be added to the catalogs list available in <oXygen/> from menu Options Preferences XML XML Catalog . Suppose you want to use the XHTML 1.0 Strict schema available at http://www.w3.org/2002/08/xhtml/xhtml1-strict.xsd Use a browser to navigate to the schema's location. Copy the schema content in a local file, xhtml1-strict.xsd for example, on your hard drive. In the same folder where you saved the schema file, create a file called catalog.xml, having the following content: <?xml version="1.0"?> <!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> <catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"> <rewriteSystem systemIdStartString="http://www.w3.org/2002/08/xhtml/" rewritePrefix="./"/> </catalog> The system ID reference or URI reference to a remote resource can also be mapped to a local copy based on the suffix of the reference using the catalog elements systemSuffix and uriSuffix, for example: <?xml version="1.0"?> <!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN" "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd"> <catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog"> <systemSuffix systemIdSuffix="xhtml1-strict.xsd" uri="file:///C:/temp/schema/xhtml/xhtml1-strict.xsd"/> </catalog> All the supported catalog elements are described in the XML catalogs Recommendation. If you saved the local copy of the XHTML 1.0 Strict schema in a different folder, let's say "C:/temp/", then you have to set the rewritePrefix as rewritePrefix="C:/temp/". A relative path specified in the rewritePrefix attribute is resolved relative to the location of the catalog file. Start <oXygen/>. Go to Options -> Preferences -> XML -> XML Catalog option page. Press the New button to add the previously created catalog file to the catalog list. After adding the catalog you must reopen the files already open in which you want to use the catalog for validation, content completion or transformation. The new XML catalog settings will take effect in any file opened after the XML catalog settings were modified. <oXygen/> provides also two document templates for creating XML catalogs. They serve as starting points in writing an XML catalog. They are called OASIS XML Catalog 1.0 and OASIS XML Catalog 1.1 and are available in the list of document templates opened from menu File New from Templates or from the New from Templates button on the File toolbar.