/**
* Get the very first value for a predicate as a string, or null if the predicate is not used
*
* @param rdf
* @param subject
* @param predicate
* @return first value for the given predicate or null if not found
*/
public static String getFirstValueForPredicate(
final Dataset rdf, final Node subject, final Node predicate) {
final Iterator<Quad> statements = rdf.asDatasetGraph().find(ANY, subject, predicate, ANY);
// we'll take the first one we get
if (statements.hasNext()) {
final Quad statement = statements.next();
LOGGER.trace("Checking statement: {}", statement);
return statement.asTriple().getObject().getLiteral().getLexicalForm();
}
LOGGER.trace("No value found for predicate: {}", predicate);
return null;
}
@Override
public void add(Quad quad) {
Graph graph;
if (quad.isDefaultGraph()) {
graph = getDefaultGraph();
} else {
graph = getGraph(quad.getGraph());
}
if (graph != null) {
graph.add(quad.asTriple());
}
}
@Override
public void compute(Quad quad) {
logger.debug("Computing : {} ", quad.asTriple().toString());
String predicate = quad.getPredicate().getURI();
if (!(predicate.equals(RDF.type))) {
if ((quad.getObject().isURI()) & (!(quad.getObject().isBlank()))) {
boolean isAdded = fqurisReservoir.add(quad.getObject().getURI());
logger.trace(
"URI found on object: {}, was added to reservoir? {}",
quad.getObject().getURI(),
isAdded);
}
}
}
@Override
public void compute(Quad quad) {
logger.debug("Computing : {} ", quad.asTriple().toString());
Node subject = quad.getSubject();
Node object = quad.getObject();
if (quad.getObject().equals(FOAF.Document.asNode())) {
docs.putIfAbsent(subject.toString(), new DigitalSignature());
}
if (quad.getPredicate().equals(ASSURANCE.asNode())) {
DigitalSignature ds;
if (endorsements.containsKey(object.getURI())) {
ds = endorsements.get(object.getURI());
} else {
ds = new DigitalSignature();
ds.endorcement = object.getURI();
}
ds.assurance = subject.getURI();
docs.put(subject.toString(), ds);
endorsements.put(object.getURI(), ds);
}
if (quad.getPredicate().equals(ENDORSER.asNode())) {
DigitalSignature ds;
if (endorsements.containsKey(object.getURI())) {
ds = endorsements.get(object.getURI());
} else {
ds = new DigitalSignature();
ds.endorcement = subject.getURI();
}
ds.endorcer = object.getURI();
}
if (quad.getObject().equals(ENDORSEMENT.asNode())) {
DigitalSignature ds = new DigitalSignature();
ds.endorcement = subject.getURI();
endorsements.putIfAbsent(subject.getURI(), ds);
}
}
@Override
public void compute(Quad quad) {
logger.debug("Assessing {}", quad.asTriple().toString());
Node predicate = quad.getPredicate();
Node object = quad.getObject();
// is it an identification of an Agent?
if (predicate.hasURI(PROV.wasAttributedTo.getURI())) {
Entity e = this.getOrPutEntity(quad.getSubject().toString());
e.agent = quad.getObject().toString();
}
// is it an activity in an entity?
if (predicate.hasURI(PROV.wasGeneratedBy.getURI())) {
Activity a = this.getOrPutActivity(quad.getObject().toString());
activityDirectory.put(quad.getSubject().toString(), a);
Entity e = this.getOrPutEntity(quad.getSubject().toString());
e.activities.add(a);
}
// is it an identification of a datasource in an activity?
if (predicate.hasURI(PROV.used.getURI())) {
Activity a = this.getOrPutActivity(quad.getSubject().toString());
a.datasource = quad.getObject().toString();
}
// is it an identification of an agent in an activity?
if (predicate.hasURI(PROV.wasAssociatedWith.getURI())
|| predicate.hasURI(PROV.actedOnBehalfOf.getURI())) {
Activity a = null;
a = this.getOrPutActivity(quad.getSubject().toString());
a.agent = quad.getObject().getURI();
}
// is it an entity?
if (object.hasURI(PROV.Entity.getURI())) {
this.getOrPutEntity(quad.getSubject().toString());
}
// is it an activity?
if (object.hasURI(PROV.Activity.getURI())) {
this.getOrPutActivity(quad.getSubject().toString());
}
}
/**
* Processes each triple obtained from the dataset to be assessed (instance declarations, that is,
* triples with predicate rdf:type are ignored). Identifies URIs appearing in both, the subject
* and object of the triple and adds them to the set of URIs to be evaluated for
* dereferenceability
*
* @param quad Triple (in quad format) to be evaluated
*/
public void compute(Quad quad) {
logger.debug("Assessing {}", quad.asTriple().toString());
// we are currently ignoring triples ?s a ?o
if (!(quad.getPredicate().getURI().equals(RDF.type.getURI()))) {
String subject = quad.getSubject().toString();
if (httpRetriever.isPossibleURL(subject)) {
logger.trace("URI found on subject: {}", subject);
addUriToDereference(subject);
}
String object = quad.getObject().toString();
if (httpRetriever.isPossibleURL(object)) {
logger.trace("URI found on object: {}", object);
addUriToDereference(object);
}
}
}