/*
* Licensed to Aduna under one or more contributor license agreements.
* See the NOTICE.txt file distributed with this work for additional
* information regarding copyright ownership.
*
* Aduna licenses this file to you under the terms of the Aduna BSD
* License (the "License"); you may not use this file except in compliance
* with the License. See the LICENSE.txt file distributed with this work
* for the full License.
*
* 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 com.bigdata.rdf.rio.json;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
import org.openrdf.model.Value;
import org.openrdf.query.QueryResultHandlerException;
import org.openrdf.query.resultio.TupleQueryResultFormat;
import org.openrdf.query.resultio.TupleQueryResultWriter;
import com.bigdata.rdf.model.BigdataBNode;
import com.bigdata.rdf.model.BigdataStatement;
/**
* A TupleQueryResultWriter that writes query results in the <a
* href="http://www.w3.org/TR/rdf-sparql-json-res/">SPARQL Query Results JSON
* Format</a>.
*/
public class BigdataSPARQLResultsJSONWriter extends SPARQLJSONWriterBase implements TupleQueryResultWriter {
/*--------------*
* Constructors *
*--------------*/
public BigdataSPARQLResultsJSONWriter(Writer writer) {
super(writer);
}
public BigdataSPARQLResultsJSONWriter(OutputStream out) {
super(out);
}
/*---------*
* Methods *
*---------*/
@Override
public final TupleQueryResultFormat getTupleQueryResultFormat() {
return TupleQueryResultFormat.JSON;
}
@Override
public TupleQueryResultFormat getQueryResultFormat() {
return getTupleQueryResultFormat();
}
@Override
protected void writeValue(final Value value) throws IOException,
QueryResultHandlerException {
if (value instanceof BigdataBNode &&
((BigdataBNode) value).isStatementIdentifier()) {
writeSid((BigdataBNode) value);
} else {
super.writeValue(value);
}
}
protected void writeSid(final BigdataBNode sid)
throws IOException, QueryResultHandlerException {
jg.writeStartObject();
jg.writeStringField("type", BigdataSPARQLResultsJSONParser.SID);
final BigdataStatement stmt = sid.getStatement();
jg.writeFieldName(BigdataSPARQLResultsJSONParser.SUBJECT);
writeValue(stmt.getSubject());
jg.writeFieldName(BigdataSPARQLResultsJSONParser.PREDICATE);
writeValue(stmt.getPredicate());
jg.writeFieldName(BigdataSPARQLResultsJSONParser.OBJECT);
writeValue(stmt.getObject());
if (stmt.getContext() != null) {
jg.writeFieldName(BigdataSPARQLResultsJSONParser.CONTEXT);
writeValue(stmt.getContext());
}
jg.writeEndObject();
}
}