Interface CatalogResolver

public interface CatalogResolver extends EntityResolver, XMLResolver, URIResolver, LSResourceResolver

A Catalog Resolver that implements SAX EntityResolver, StAX XMLResolver, DOM LS LSResourceResolver used by Schema Validation, and Transform URIResolver, and resolves external references using catalogs.

The Catalog Standard distinguished external identifiers from uri entries as being used to solely identify DTDs, while uri entries for other resources such as stylesheets and schema. The Java APIs, such as XMLResolver and LSResourceResolver however, make no such distinction. In consistent with the existing Java API, this CatalogResolver recognizes a system identifier as a URI and will search both system and uri entries in a catalog in order to find a matching entry.

The search is started in the current catalog. If a match is found, no further attempt will be made. Only if there is no match in the current catalog, will alternate catalogs including delegate and next catalogs be considered.

Search Order

The resolver will first search the system-type of entries with the specified systemId. The system entries include system, rewriteSystem and systemSuffix entries.

If no match is found, public entries may be searched in accordance with the prefer attribute.

The prefer attribute: if the prefer is public, and there is no match found through the system entries, public entries will be considered. If it is not specified, the prefer is public by default (Note that by the OASIS standard, system entries will always be considered before public entries. Prefer public means that public entries will be matched when both system and public identifiers are specified. In general therefore, prefer public is recommended.)

If no match is found with the systemId and public identifier, the resolver will continue searching uri entries with the specified systemId or href. The uri entries include uri, rewriteURI, and uriSuffix entries.

Error Handling

The interfaces that the CatalogResolver extend specified checked exceptions, including:

• SAXException and IOException by EntityResolver.resolveEntity(java.lang.String, java.lang.String)
• XMLStreamException by XMLResolver.resolveEntity(java.lang.String, java.lang.String, java.lang.String, java.lang.String)
• TransformerException by URIResolver.resolve(java.lang.String, java.lang.String)

The CatalogResolver however, will throw CatalogException only when javax.xml.catalog.resolve is specified as strict. For applications that expect to handle the checked Exceptions, it may be necessary to use a custom resolver to wrap the CatalogResolver or implement it with a Catalog object.