/* The contents of this file are subject to the license and copyright terms
* detailed in the license directory at the root of the source tree (also
* available online at http://fedora-commons.org/license/).
*/
package org.fcrepo.server.resourceIndex;
import java.net.URI;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.jrdf.graph.ObjectNode;
import org.jrdf.graph.Triple;
import org.jrdf.graph.URIReference;
import org.fcrepo.common.Constants;
import org.fcrepo.common.PID;
import org.fcrepo.common.rdf.RDFName;
import org.fcrepo.common.rdf.SimpleLiteral;
import org.fcrepo.common.rdf.SimpleTriple;
import org.fcrepo.common.rdf.SimpleURIReference;
import org.fcrepo.server.errors.ResourceIndexException;
import org.fcrepo.server.storage.DOReader;
import org.fcrepo.server.storage.types.Datastream;
import org.fcrepo.server.storage.types.RelationshipTuple;
import org.fcrepo.server.utilities.DCField;
import org.fcrepo.server.utilities.DCFields;
/**
* Generates basic RDF triples for Fedora 3.0 objects.
*
* @author Chris Wilper
*/
public class FedoraObjectTripleGenerator_3_0
extends TripleGeneratorBase
implements Constants, TripleGenerator {
/**
* {@inheritDoc}
*/
public Set<Triple> getTriplesForObject(DOReader reader)
throws ResourceIndexException {
Set<Triple> set = new HashSet<Triple>();
addCommonTriples(reader, set);
return set;
}
/**
* Add the common core and datastream triples for the given object.
*/
private URIReference addCommonTriples(DOReader reader, Set<Triple> set)
throws ResourceIndexException {
try {
URIReference objURI = new SimpleURIReference(
new URI(PID.toURI(reader.GetObjectPID())));
addCoreObjectTriples(reader, objURI, set);
Datastream[] datastreams = reader.GetDatastreams(null, null);
for (Datastream ds : datastreams) {
addCoreDatastreamTriples(ds, objURI, set);
if (ds.DatastreamID.equals("DC")) {
addDCTriples(ds, objURI, set);
}
}
addRelationshipTriples(reader, objURI, set);
return objURI;
} catch (ResourceIndexException e) {
throw e;
} catch (Exception e) {
throw new ResourceIndexException("Error generating triples", e);
}
}
/**
* For the given object, add the common core system metadata triples. This
* will include:
* <ul>
* <li> object <i>model:createdDate</i></li>
* <li> object <i>model:label</i></li>
* <li> object <i>model:owner</i></li>
* <li> object <i>model:state</i></li>
* <li> object <i>view:lastModifiedDate</i></li>
* </ul>
*/
private void addCoreObjectTriples(DOReader r,
URIReference objURI,
Set<Triple> set) throws Exception {
add(objURI, MODEL.CREATED_DATE, r.getCreateDate(), set);
add(objURI, MODEL.LABEL, r.GetObjectLabel(), set);
add(objURI, MODEL.OWNER, r.getOwnerId(), set);
add(objURI, MODEL.STATE, getStateResource(r.GetObjectState()), set);
add(objURI, VIEW.LAST_MODIFIED_DATE, r.getLastModDate(), set);
}
/**
* For the given datastream, add the triples that are common for all
* datastreams. This will include:
* <ul>
* <li> object <i>view:disseminates</i> datastream</li>
* <li> datastream <i>view:disseminationType</i></li>
* <li> datastream <i>view:isVolatile</i></li>
* <li> datastream <i>view:lastModifiedDate</i></li>
* <li> datastream <i>view:mimeType</i></li>
* <li> datastream <i>model:state</i></li>
* </ul>
*/
private void addCoreDatastreamTriples(Datastream ds,
URIReference objURI,
Set<Triple> set) throws Exception {
URIReference dsURI = new SimpleURIReference(
new URI(objURI.getURI().toString() + "/" + ds.DatastreamID));
add(objURI, VIEW.DISSEMINATES, dsURI, set);
URIReference dsDissType = new SimpleURIReference(
new URI(FEDORA.uri + "*/" + ds.DatastreamID));
add(dsURI, VIEW.DISSEMINATION_TYPE, dsDissType, set);
boolean isVolatile =
ds.DSControlGrp.equals("E") || ds.DSControlGrp.equals("R");
add(dsURI, VIEW.IS_VOLATILE, isVolatile, set);
add(dsURI, VIEW.LAST_MODIFIED_DATE, ds.DSCreateDT, set);
add(dsURI, VIEW.MIME_TYPE, ds.DSMIME, set);
add(dsURI, MODEL.STATE, getStateResource(ds.DSState), set);
}
/**
* Add a statement about the object for each predicate, value pair expressed
* in the DC datastream.
*/
private void addDCTriples(Datastream ds,
URIReference objURI,
Set<Triple> set) throws Exception {
DCFields dc = new DCFields(ds.getContentStream());
Map<RDFName, List<DCField>> map = dc.getMap();
for (RDFName predicate : map.keySet()) {
for (DCField dcField : map.get(predicate)) {
String lang = dcField.getLang();
if (lang == null) {
add(objURI, predicate, dcField.getValue(), set);
} else {
add(objURI, predicate, dcField.getValue(), lang, set);
}
}
}
}
/**
* Adds all triples given by reader.getRelationships(null, null).
* <p>
* This includes everything in RELS-EXT and RELS-INT as well as the implicit
* basic content model assertion, if any.
*/
private void addRelationshipTriples(DOReader reader,
URIReference objURI,
Set<Triple> set)
throws Exception {
for (RelationshipTuple tuple : reader.getRelationships()) {
ObjectNode oNode;
if (tuple.isLiteral) {
if (tuple.datatype != null) {
oNode = new SimpleLiteral(tuple.object,
tuple.datatype);
} else if (tuple.language != null){
oNode = new SimpleLiteral(tuple.object, tuple.language);
} else {
oNode = new SimpleLiteral(tuple.object);
}
} else {
oNode = new SimpleURIReference(new URI(tuple.object));
}
set.add(new SimpleTriple(new SimpleURIReference(
new URI(tuple.subject)),
new SimpleURIReference(
new URI(tuple.predicate)),
oNode));
}
}
}