package de.fuberlin.wiwiss.d2rq.server;
import java.io.IOException;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.velocity.context.Context;
import com.hp.hpl.jena.graph.Node;
import com.hp.hpl.jena.query.QueryCancelledException;
import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.rdf.model.Resource;
import com.hp.hpl.jena.rdf.model.ResourceFactory;
import com.hp.hpl.jena.rdf.model.Statement;
import com.hp.hpl.jena.rdf.model.StmtIterator;
import com.hp.hpl.jena.shared.PrefixMapping;
import com.hp.hpl.jena.sparql.vocabulary.FOAF;
import com.hp.hpl.jena.vocabulary.DC;
import com.hp.hpl.jena.vocabulary.DCTerms;
import com.hp.hpl.jena.vocabulary.RDFS;
import de.fuberlin.wiwiss.d2rq.ClassMapLister;
import de.fuberlin.wiwiss.d2rq.ResourceDescriber;
import de.fuberlin.wiwiss.d2rq.vocab.SKOS;
public class PageServlet extends HttpServlet {
private PrefixMapping prefixes;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
D2RServer server = D2RServer.fromServletContext(getServletContext());
server.checkMappingFileChanged();
String relativeResourceURI = request.getRequestURI().substring(
request.getContextPath().length()
+ request.getServletPath().length());
// Some servlet containers keep the leading slash, some don't
if (!"".equals(relativeResourceURI)
&& "/".equals(relativeResourceURI.substring(0, 1))) {
relativeResourceURI = relativeResourceURI.substring(1);
}
if (request.getQueryString() != null) {
relativeResourceURI = relativeResourceURI + "?"
+ request.getQueryString();
}
/* Determine service stem, i.e. vocab/ in /[vocab/]page */
int servicePos;
if (-1 == (servicePos = request.getServletPath().indexOf(
"/" + D2RServer.getPageServiceName())))
throw new ServletException("Expected to find service path /"
+ D2RServer.getPageServiceName());
String serviceStem = request.getServletPath().substring(1,
servicePos + 1);
String resourceURI = server.resourceBaseURI(serviceStem)
+ relativeResourceURI;
String documentURL = server.dataURL(serviceStem, relativeResourceURI);
String pageURL = server.pageURL(serviceStem, relativeResourceURI);
VelocityWrapper velocity = new VelocityWrapper(this, request, response);
Context context = velocity.getContext();
context.put("uri", resourceURI);
// Build resource description
Resource resource = ResourceFactory.createResource(resourceURI);
boolean outgoingTriplesOnly = server.isVocabularyResource(resource)
&& !server.getConfig().getVocabularyIncludeInstances();
int limit = server.getConfig().getLimitPerPropertyBridge();
Model description = null;
try {
ResourceDescriber describer = new ResourceDescriber(
server.getMapping(), resource.asNode(), outgoingTriplesOnly,
limit, Math.round(server.getConfig().getPageTimeout() * 1000));
description = ModelFactory.createModelForGraph(describer.description());
} catch (QueryCancelledException ex) {
velocity.reportError(
504, "504 Gateway Timeout", "The operation timed out.");
return;
}
if (description.size() == 0) {
velocity.reportError(404, "404 Not Found", "No resource with this identifier exists in the database.");
return;
}
// Get a Resource that is attached to the description model
resource = description.getResource(resourceURI);
this.prefixes = server.getPrefixes(); // model();
if (server.getConfig().serveMetadata()) {
// create and add metadata to context
MetadataCreator resourceMetadataCreator = new MetadataCreator(
server, server.getConfig().getResourceMetadataTemplate(
server, getServletContext()));
Model metadata = resourceMetadataCreator.addMetadataFromTemplate(
resourceURI, documentURL, pageURL);
if (!metadata.isEmpty()) {
List<Statement> mList = metadata.getResource(documentURL)
.listProperties().toList();
Collections.sort(mList, MetadataCreator.subjectSorter);
context.put("metadata", mList);
context.put("metadataroot", metadata.getResource(documentURL));
// add prefixes to context
Map<String, String> nsSet = metadata.getNsPrefixMap();
nsSet.putAll(description.getNsPrefixMap());
context.put("prefixes", nsSet.entrySet());
context.put("renderedNodesMap",
new HashMap<Resource, Boolean>());
// add a empty map for keeping track of blank nodes aliases
context.put("blankNodesMap", new HashMap<Resource, String>());
} else {
context.put("metadata", Boolean.FALSE);
}
} else {
context.put("metadata", Boolean.FALSE);
}
context.put("rdf_link", documentURL);
context.put("label", getBestLabel(resource));
context.put("properties", collectProperties(description, resource));
context.put("classmap_links", classmapLinks(resource));
context.put("limit_per_property_bridge", limit > 0 ? limit : null);
velocity.mergeTemplateXHTML("resource_page.vm");
}
private Collection<Property> collectProperties(Model m, Resource r) {
Collection<Property> result = new TreeSet<Property>();
StmtIterator it = r.listProperties();
while (it.hasNext()) {
result.add(new Property(it.nextStatement(), false));
}
it = m.listStatements(null, null, r);
while (it.hasNext()) {
result.add(new Property(it.nextStatement(), true));
}
return result;
}
private Map<String, String> classmapLinks(Resource resource) {
Map<String, String> result = new HashMap<String, String>();
D2RServer server = D2RServer.fromServletContext(getServletContext());
for (String name : getClassMapLister().classMapNamesForResource(
resource.asNode())) {
result.put(name, server.baseURI() + "directory/" + name);
}
return result;
}
private ClassMapLister getClassMapLister() {
return D2RServer.retrieveSystemLoader(getServletContext())
.getClassMapLister();
}
private static final long serialVersionUID = 2752377911405801794L;
public class Property implements Comparable<Property> {
private Node property;
private Node value;
private boolean isInverse;
Property(Statement stmt, boolean isInverse) {
this.property = stmt.getPredicate().asNode();
if (isInverse) {
this.value = stmt.getSubject().asNode();
} else {
this.value = stmt.getObject().asNode();
}
this.isInverse = isInverse;
}
public boolean isInverse() {
return this.isInverse;
}
public String propertyURI() {
return this.property.getURI();
}
public String propertyQName() {
String qname = prefixes.shortForm(this.property.getURI());
if (qname == null) {
return "<" + this.property.getURI() + ">";
}
return qname;
}
public String propertyPrefix() {
String qname = propertyQName();
if (qname.startsWith("<")) {
return null;
}
return qname.substring(0, qname.indexOf(":") + 1);
}
public String propertyLocalName() {
String qname = propertyQName();
if (qname.startsWith("<")) {
return this.property.getLocalName();
}
return qname.substring(qname.indexOf(":") + 1);
}
public Node value() {
return this.value;
}
public String valueQName() {
if (!this.value.isURI()) {
return null;
}
return prefixes.qnameFor(this.value.getURI());
}
public String datatypeQName() {
String qname = prefixes
.qnameFor(this.value.getLiteralDatatypeURI());
if (qname == null) {
return "<" + this.value.getLiteralDatatypeURI() + ">";
}
return qname;
}
public boolean isImg() {
return FOAF.img.asNode().equals(property)
|| FOAF.depiction.asNode().equals(property)
|| FOAF.thumbnail.asNode().equals(property);
}
public int compareTo(Property other) {
String propertyLocalName = this.property.getLocalName();
String otherLocalName = other.property.getLocalName();
if (propertyLocalName.compareTo(otherLocalName) != 0) {
return propertyLocalName.compareTo(otherLocalName);
}
if (propertyPrefix().compareTo(other.propertyPrefix()) != 0) {
return propertyPrefix().compareTo(other.propertyPrefix());
}
if (propertyURI().compareTo(other.propertyURI()) != 0) {
return propertyURI().compareTo(other.propertyURI());
}
if (this.isInverse != other.isInverse) {
return (this.isInverse) ? -1 : 1;
}
if (this.value.isURI() || other.value.isURI()) {
if (!other.value.isURI()) {
return 1;
}
if (!this.value.isURI()) {
return -1;
}
return this.value.getURI().compareTo(other.value.getURI());
}
if (this.value.isBlank() || other.value.isBlank()) {
if (!other.value.isBlank()) {
return -1;
}
if (!this.value.isBlank()) {
return 1;
}
return this.value.getBlankNodeLabel().compareTo(
other.value.getBlankNodeLabel());
}
// TODO Typed literals, language literals
return this.value.getLiteralLexicalForm().compareTo(
other.value.getLiteralLexicalForm());
}
}
public static Statement getBestLabel(Resource resource) {
Statement label = resource.getProperty(RDFS.label);
if (label == null)
label = resource.getProperty(SKOS.prefLabel);
if (label == null)
label = resource.getProperty(DC.title);
if (label == null)
label = resource.getProperty(DCTerms.title);
if (label == null)
label = resource.getProperty(FOAF.name);
return label;
}
}