/**
* Check if relation type is registered predicate.
*
* @param predicate the predicate as URI
* @throws InvalidContentException Thrown if predicate is invalid
* @throws WebserverSystemException Thrown if internal error occur
* @throws RelationPredicateNotFoundException Thrown if the predicate is not registered.
*/
private static void checkRelationType(final URI predicate)
throws RelationPredicateNotFoundException {
if (!ContentRelationsUtility.validPredicate(predicate)) {
throw new RelationPredicateNotFoundException(
"Predicate " + predicate + " is not on the registered predicate list. ");
}
}
/**
* Retrieves a list of registered predicates which can be used to create content relations.
*
* @return String containing a list with registered predicates.
* @throws InvalidContentException Thrown if a xml file with an ontology has invalid content
* @throws InvalidXmlException Thrown if a xml file with an ontology is invalid rdf/xml
* @throws SystemException e
*/
@Override
public String retrieveRegisteredPredicates()
throws InvalidContentException, InvalidXmlException, SystemException {
final List<String> predicates = ContentRelationsUtility.getPredicates();
final Iterator<String> it = predicates.iterator();
final StringBuilder sb = new StringBuilder();
sb.append(Constants.XML_HEADER);
sb.append("<registeredPredicates:predicates");
sb.append(
" xmlns:registeredPredicates=\"http://www.escidoc.org/schemas/predicate-list/0.1\" >\n");
while (it.hasNext()) {
sb.append("<registeredPredicates:predicate>");
sb.append(it.next());
sb.append("</registeredPredicates:predicate>\n");
}
sb.append("</registeredPredicates:predicates>\n");
return sb.toString();
}