/*
* 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.openjena.riot.out;
import java.io.OutputStream ;
import java.io.Writer ;
import java.util.HashMap ;
import java.util.HashSet ;
import java.util.Map ;
import java.util.Set ;
import org.openjena.atlas.lib.Pair ;
import org.openjena.atlas.lib.Sink ;
import org.openjena.riot.system.Prologue ;
import org.openjena.riot.system.SyntaxLabels ;
import com.hp.hpl.jena.graph.Graph ;
import com.hp.hpl.jena.graph.Node ;
import com.hp.hpl.jena.graph.Triple ;
import com.hp.hpl.jena.graph.query.QueryHandler ;
import com.hp.hpl.jena.util.iterator.ExtendedIterator ;
public class RDFJSONWriter {
public static void write (OutputStream out, Graph graph) {
Prologue prologue = Prologue.create(null, null) ; // (null, graph.getPrefixMapping()) ;
Sink<Pair<Node, Map<Node, Set<Node>>>> sink = new SinkEntityOutput(out, prologue, SyntaxLabels.createNodeToLabel()) ;
write ( sink, graph ) ;
}
public static void write (Writer out, Graph graph) {
Prologue prologue = Prologue.create(null, null) ; // (null, graph.getPrefixMapping()) ;
Sink<Pair<Node, Map<Node, Set<Node>>>> sink = new SinkEntityOutput(out, prologue, SyntaxLabels.createNodeToLabel()) ;
write ( sink, graph ) ;
}
private static void write (Sink<Pair<Node, Map<Node, Set<Node>>>> sink, Graph graph) {
QueryHandler queryHandler = graph.queryHandler() ;
ExtendedIterator<Node> subjects = queryHandler.subjectsFor(Node.ANY, Node.ANY) ;
try {
Map<Node, Set<Node>> predicates = new HashMap<Node, Set<Node>>() ;
while ( subjects.hasNext() ) {
Node subject = subjects.next() ;
ExtendedIterator<Triple> triples = graph.find(subject, Node.ANY, Node.ANY) ;
try {
while ( triples.hasNext() ) {
Triple triple = triples.next() ;
Node p = triple.getPredicate() ;
if ( predicates.containsKey(p) ) {
predicates.get(p).add(triple.getObject()) ;
} else {
Set<Node> objects = new HashSet<Node>() ;
objects.add(triple.getObject()) ;
predicates.put(p, objects) ;
}
}
} finally {
if ( triples != null ) triples.close() ;
}
sink.send(new Pair<Node, Map<Node, Set<Node>>>(subject, predicates)) ;
predicates.clear() ;
}
} finally {
if ( subjects != null ) subjects.close() ;
sink.close() ;
}
}
}