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Commentary

Mark Wahl


Web Design by
Kristen Lanum

Commentary by Mark Wahl, CISA

Organizing principles for systems:
Schemat Consumer (2007/4/7)

Informed Control released today the first version of the Schemat Consumer, a proof of concept research implementation of attribute type metadata parsing.

The Schemat Consumer provides applications in an identity metasystem with a simple Java API for retrieving the metadata of URI-named attribute types.

SchematConsumer sc = SchematConsumer.getInstance();
// ...
IAttributeTypeMetadataClasses iatmc = sc.findAttributeTypeMetadataFromSubjectUri(new URI(attribute_type));
CommonAttributeTypeMetadata c = new CommonAttributeTypeMetadata(iatmc);
String label = c.getLabel(); // get display label for the attribute type
String comment = c.getComment(); // get display comment for the attribute type
List seealso = c.getSeeAlsoUriStringsList(); // get URIs of 'see also' 
boolean isequiv = c.isEquivalentToUri(another_attribute_type); // test are two attribute types equivalent?
List acq_uris = c.getAcquisitionUriStringsList(); // get URIs where to acquire values of this attribute
List auth_uris = c.getAuthorityUriStringsList(); // get URIs of authorities for this attribute
String example = c.getValueExampleString(); // get String example value of this attribute
HigginsValuePropertyDatatype v = c.getHigginsValuePropertyDatatype();
if (v != null) {
String pattern = v.getPatternString();  // get regular expression of value syntax
}
String xhtml = c.summarizeAttributeTypeAsXhtml(); // get XHTML fragment describing the attribute

Schemat Consumer wraps the Jakarta HTTP core client library and the HP Labs Jena ARP2 RDF parser. As of 2007 April 7, it implements the http and file URI schemes to retrieve the RDF/XML encoding of metadata, and a subset of metadata elements defined by W3C, Dublin Core, Higgins and OpenID. Future versions are anticipated to implement the full set of Identity Schemas metadata.