| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.clerezza.jaxrs.rdf.providers; |
| |
| import org.apache.clerezza.rdf.core.serializedform.Serializer; |
| import org.apache.clerezza.rdf.core.serializedform.SupportedFormat; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.lang.annotation.Annotation; |
| import java.lang.reflect.Type; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Set; |
| |
| import javax.ws.rs.Produces; |
| import javax.ws.rs.WebApplicationException; |
| import javax.ws.rs.core.Context; |
| import javax.ws.rs.core.MediaType; |
| import javax.ws.rs.core.MultivaluedMap; |
| import javax.ws.rs.core.UriInfo; |
| import javax.ws.rs.ext.MessageBodyWriter; |
| import javax.ws.rs.ext.Provider; |
| |
| import org.apache.clerezza.commons.rdf.RDFTerm; |
| import org.apache.clerezza.commons.rdf.Triple; |
| import org.apache.clerezza.commons.rdf.Graph; |
| import org.apache.clerezza.commons.rdf.IRI; |
| import org.apache.clerezza.commons.rdf.impl.utils.simple.SimpleGraph; |
| import org.apache.clerezza.rdf.utils.GraphNode; |
| import org.apache.felix.scr.annotations.Component; |
| import org.apache.felix.scr.annotations.Property; |
| import org.apache.felix.scr.annotations.Reference; |
| import org.apache.felix.scr.annotations.Service; |
| |
| /** |
| * By default this returns a serialization of the context of the GraphNode. |
| * |
| * The expansion can be widened by using the query parameters xPropObj and |
| * xProSubj. These parameters specify property uris (both parameters might be |
| * repeated). For the specified properties their objects respectively subjects |
| * are expanded as if they were bnodes. |
| * |
| * |
| * @author reto |
| */ |
| |
| @Component |
| @Service(Object.class) |
| @Property(name = "javax.ws.rs", boolValue = true) |
| @Provider |
| @Produces({SupportedFormat.N3, SupportedFormat.N_TRIPLE, |
| SupportedFormat.RDF_XML, SupportedFormat.TURTLE, |
| SupportedFormat.X_TURTLE, SupportedFormat.RDF_JSON}) |
| public class GraphNodeWriter implements MessageBodyWriter<GraphNode> { |
| |
| public static final String OBJ_EXP_PARAM = "xPropObj"; |
| public static final String SUBJ_EXP_PARAM = "xPropSubj"; |
| |
| @Reference |
| private Serializer serializer; |
| private UriInfo uriInfo; |
| |
| @Override |
| public boolean isWriteable(Class<?> type, Type genericType, |
| Annotation[] annotations, MediaType mediaType) { |
| return GraphNode.class.isAssignableFrom(type); |
| } |
| |
| @Override |
| public long getSize(GraphNode n, Class<?> type, Type genericType, |
| Annotation[] annotations, MediaType mediaType) { |
| return -1; |
| } |
| |
| @Override |
| public void writeTo(GraphNode node, Class<?> type, Type genericType, |
| Annotation[] annotations, MediaType mediaType, |
| MultivaluedMap<String, Object> httpHeaders, |
| OutputStream entityStream) throws IOException, WebApplicationException { |
| serializer.serialize(entityStream, getExpandedContext(node), mediaType.toString()); |
| } |
| |
| @Context |
| public void setUriInfo(UriInfo uriInfo) { |
| this.uriInfo = uriInfo; |
| } |
| |
| private Graph getExpandedContext(GraphNode node) { |
| final Graph result = new SimpleGraph(node.getNodeContext()); |
| final Set<RDFTerm> expandedResources = new HashSet<RDFTerm>(); |
| expandedResources.add(node.getNode()); |
| while (true) { |
| Set<RDFTerm> additionalExpansionRes = getAdditionalExpansionResources(result); |
| additionalExpansionRes.removeAll(expandedResources); |
| if (additionalExpansionRes.size() == 0) { |
| return result; |
| } |
| for (RDFTerm resource : additionalExpansionRes) { |
| final GraphNode additionalNode = new GraphNode(resource, node.getGraph()); |
| result.addAll(additionalNode.getNodeContext()); |
| expandedResources.add(resource); |
| } |
| } |
| } |
| |
| private Set<RDFTerm> getAdditionalExpansionResources(Graph tc) { |
| final Set<IRI> subjectExpansionProperties = getSubjectExpansionProperties(); |
| final Set<IRI> objectExpansionProperties = getObjectExpansionProperties(); |
| final Set<RDFTerm> result = new HashSet<RDFTerm>(); |
| if ((subjectExpansionProperties.size() > 0) |
| || (objectExpansionProperties.size() > 0)) { |
| for (Triple triple : tc) { |
| final IRI predicate = triple.getPredicate(); |
| if (subjectExpansionProperties.contains(predicate)) { |
| result.add(triple.getSubject()); |
| } |
| if (objectExpansionProperties.contains(predicate)) { |
| result.add(triple.getObject()); |
| } |
| } |
| } |
| return result; |
| } |
| |
| private Set<IRI> getSubjectExpansionProperties() { |
| final MultivaluedMap<String, String> queryParams = uriInfo.getQueryParameters(); |
| final List<String> paramValues = queryParams.get(SUBJ_EXP_PARAM); |
| if (paramValues == null) { |
| return new HashSet<IRI>(0); |
| } |
| final Set<IRI> result = new HashSet<IRI>(paramValues.size()); |
| for (String uriString : paramValues) { |
| result.add(new IRI(uriString)); |
| } |
| return result; |
| } |
| |
| private Set<IRI> getObjectExpansionProperties() { |
| final MultivaluedMap<String, String> queryParams = uriInfo.getQueryParameters(); |
| final List<String> paramValues = queryParams.get(OBJ_EXP_PARAM); |
| if (paramValues == null) { |
| return new HashSet<IRI>(0); |
| } |
| final Set<IRI> result = new HashSet<IRI>(paramValues.size()); |
| for (String uriString : paramValues) { |
| result.add(new IRI(uriString)); |
| } |
| return result; |
| } |
| } |