The Catalog class represents an entity Catalog as defined by
XML Catalogs, OASIS Standard V1.1, 7 October 2005 .
A catalog is an XML file that contains a root catalog
entry with a list of catalog entries. The entries can also be grouped with a group
entry. The catalog and group entries may specify prefer
and xml:base
attributes that set preference of public or system type of entries and base URI to resolve relative URIs.
A catalog can be used in two situations:
- Locate the external resources with a public or system identifier;
- Locate an alternate URI reference with a URI.
For case 1, the standard defines 6 External Identifier Entries:
public, system, rewriteSystem, systemSuffix, delegatePublic, and delegateSystem
.
While for case 2, it defines 4 URI Entries:
uri, rewriteURI, uriSuffix and delegateURI
.
In addition to the above entry types, a catalog may define nextCatalog entries to add additional catalog entry files.