/**
* Populates the namespaces map with default namespaces and namespaces used by the graph.
*
* @param graph Graph
* @throws GraphException
*/
protected void populateNamespaces(Graph graph) throws GraphException {
// default namespaces
namespaces = new HashMap<String, String>();
namespaces.put(RDF_PREFIX, RDF.BASE_URI.toString());
namespaces.put(RDFS_PREFIX, RDFS.BASE_URI.toString());
namespaces.put("owl", "http://www.w3.org/2002/07/owl#");
namespaces.put("dc", "http://purl.org/dc/elements/1.1/");
// validate graph before reading
if (graph == null) {
throw new IllegalArgumentException("Graph argument is null.");
}
// get all statements
ClosableIterator<Triple> tripleIter = graph.find(null, null, null);
if (tripleIter != null) {
while (tripleIter.hasNext()) {
// get the next triple
Triple triple = tripleIter.next();
if (triple != null) {
// evaluate subject
SubjectNode subject = triple.getSubject();
if (subject instanceof URIReference) {
addNamespaceURI(((URIReference) subject).getURI());
}
// evaluate predicate (must be URIReference)
PredicateNode predicate = triple.getPredicate();
addNamespaceURI(((URIReference) predicate).getURI());
// evaluate object
ObjectNode object = triple.getObject();
if (object instanceof URIReference) {
addNamespaceURI(((URIReference) object).getURI());
}
}
}
// close the Iterator
tripleIter.close();
}
}
/**
* Evaluates a URI and adds it to the namespace map as a namespace.
*
* @param uri URI
*/
protected void addNamespaceURI(URI uri) {
if (uri == null) {
throw new IllegalArgumentException("URI argument is null.");
}
// extract URI without fragment
String uriString = uri.toString();
String newURI = null;
if (uriString != null) {
// determine what comes last a '#' or '/'
int hashindex = uriString.lastIndexOf('#');
int slashindex = uriString.lastIndexOf('/');
// validate (URI must contain a forward slash)
if (slashindex == -1) {
// namespace may have been evaluated already
return;
}
// is there a '/' after the '#'?
if (slashindex > hashindex) {
// remove everything after the last '/'
int index = uriString.lastIndexOf('/');
newURI = uriString.substring(0, index) + "/";
} else {
// '#' comes after last '/' (remove entire fragment)
newURI = uriString.replaceAll(uri.getFragment(), "");
}
// only add namespace if it is new
if ((newURI != null) && (!namespaces.containsValue(newURI))) {
// add to namespaces
namespaces.put("ns" + namespaces.size(), newURI);
}
}
}
