/*
* 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.InputStream;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.openrdf.model.Value;
import org.openrdf.model.ValueFactory;
import org.openrdf.query.BindingSet;
import org.openrdf.query.QueryResultHandlerException;
import org.openrdf.query.impl.MapBindingSet;
import org.openrdf.query.resultio.QueryResultParseException;
import org.openrdf.query.resultio.QueryResultParserBase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
/**
* Abstract base class for SPARQL Results JSON Parsers. Provides a common
* implementation of both boolean and tuple parsing.
* <p>
* Bigdata Changes:
* <ul>
* <li>Changed the visibility of the method parseValue() from private to
* protected so we could override it.</li>
* <li>Pulled some code out of parseQueryResultInternal into its own method so
* that we can override it.</li>
* </ul>
*
* @author Peter Ansell
* @author Sebastian Schaffert
*/
public abstract class SPARQLJSONParserBase extends QueryResultParserBase {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
private static final JsonFactory JSON_FACTORY = new JsonFactory();
static {
JSON_FACTORY.disable(JsonFactory.Feature.INTERN_FIELD_NAMES);
JSON_FACTORY.disable(JsonFactory.Feature.CANONICALIZE_FIELD_NAMES);
JSON_FACTORY.disable(JsonGenerator.Feature.AUTO_CLOSE_TARGET);
}
public static final String HEAD = "head";
public static final String LINK = "link";
public static final String VARS = "vars";
public static final String BOOLEAN = "boolean";
public static final String RESULTS = "results";
public static final String BINDINGS = "bindings";
public static final String TYPE = "type";
public static final String VALUE = "value";
public static final String XMLLANG = "xml:lang";
public static final String DATATYPE = "datatype";
public static final String LITERAL = "literal";
public static final String TYPED_LITERAL = "typed-literal";
public static final String BNODE = "bnode";
public static final String URI = "uri";
/**
* Backwards compatibility with very early version of original SPARQL spec.
*/
private static final String DISTINCT = "distinct";
/**
* Backwards compatibility with very early version of original SPARQL spec.
*/
private static final String ORDERED = "ordered";
/**
*
*/
public SPARQLJSONParserBase() {
super();
}
/**
*
*/
public SPARQLJSONParserBase(ValueFactory valueFactory) {
super(valueFactory);
}
@Override
public void parseQueryResult(InputStream in)
throws IOException, QueryResultParseException, QueryResultHandlerException
{
parseQueryResultInternal(in, true, true);
}
protected boolean parseQueryResultInternal(InputStream in, boolean attemptParseBoolean,
boolean attemptParseTuple)
throws IOException, QueryResultParseException, QueryResultHandlerException
{
if (!attemptParseBoolean && !attemptParseTuple) {
throw new IllegalArgumentException(
"Internal error: Did not specify whether to parse as either boolean and/or tuple");
}
JsonParser jp = JSON_FACTORY.createParser(in);
boolean result = false;
if (jp.nextToken() != JsonToken.START_OBJECT) {
throw new QueryResultParseException("Expected SPARQL Results JSON document to start with an Object",
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
List<String> varsList = new ArrayList<String>();
boolean varsFound = false;
Set<BindingSet> bindings = new HashSet<BindingSet>();
while (jp.nextToken() != JsonToken.END_OBJECT) {
final String baseStr = jp.getCurrentName();
if (baseStr.equals(HEAD)) {
if (jp.nextToken() != JsonToken.START_OBJECT) {
throw new QueryResultParseException("Did not find object under " + baseStr + " field",
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
while (jp.nextToken() != JsonToken.END_OBJECT) {
final String headStr = jp.getCurrentName();
if (headStr.equals(VARS)) {
if (!attemptParseTuple) {
throw new QueryResultParseException(
"Found tuple results variables when attempting to parse SPARQL Results JSON to boolean result");
}
if (jp.nextToken() != JsonToken.START_ARRAY) {
throw new QueryResultParseException("Expected variable labels to be an array",
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
while (jp.nextToken() != JsonToken.END_ARRAY) {
varsList.add(jp.getText());
}
if (this.handler != null) {
handler.startQueryResult(varsList);
}
varsFound = true;
// If the bindings were populated before this point push them
// out now.
if (!bindings.isEmpty() && this.handler != null) {
for (BindingSet nextBinding : bindings) {
handler.handleSolution(nextBinding);
handler.endQueryResult();
}
bindings.clear();
}
}
else if (headStr.equals(LINK)) {
List<String> linksList = new ArrayList<String>();
if (jp.nextToken() != JsonToken.START_ARRAY) {
throw new QueryResultParseException("Expected links to be an array",
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
while (jp.nextToken() != JsonToken.END_ARRAY) {
linksList.add(jp.getText());
}
if (this.handler != null) {
handler.handleLinks(linksList);
}
}
else {
throw new QueryResultParseException("Found unexpected object in head field: " + headStr,
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
}
}
else if (baseStr.equals(RESULTS)) {
if (!attemptParseTuple) {
throw new QueryResultParseException(
"Found tuple results bindings when attempting to parse SPARQL Results JSON to boolean result");
}
if (jp.nextToken() != JsonToken.START_OBJECT) {
throw new QueryResultParseException("Found unexpected token in results object: "
+ jp.getCurrentName(), jp.getCurrentLocation().getLineNr(),
jp.getCurrentLocation().getColumnNr());
}
while (jp.nextToken() != JsonToken.END_OBJECT) {
if (jp.getCurrentName().equals(BINDINGS)) {
if (jp.nextToken() != JsonToken.START_ARRAY) {
throw new QueryResultParseException("Found unexpected token in bindings object",
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
while (jp.nextToken() != JsonToken.END_ARRAY) {
MapBindingSet nextBindingSet = new MapBindingSet();
if (jp.getCurrentToken() != JsonToken.START_OBJECT) {
throw new QueryResultParseException("Did not find object in bindings array: "
+ jp.getCurrentName(), jp.getCurrentLocation().getLineNr(),
jp.getCurrentLocation().getColumnNr());
}
while (jp.nextToken() != JsonToken.END_OBJECT) {
if (jp.getCurrentToken() != JsonToken.FIELD_NAME) {
throw new QueryResultParseException("Did not find binding name",
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
final String bindingStr = jp.getCurrentName();
if (jp.nextToken() != JsonToken.START_OBJECT) {
throw new QueryResultParseException("Did not find object for binding value",
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Start Bigdata Changes ~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
final Value value = parseValue(bindingStr, jp);
nextBindingSet.addBinding(bindingStr, value);
// String lang = null;
// String type = null;
// String datatype = null;
// String value = null;
//
// while (jp.nextToken() != JsonToken.END_OBJECT) {
//
// if (jp.getCurrentToken() != JsonToken.FIELD_NAME) {
// throw new QueryResultParseException("Did not find value attribute under "
// + bindingStr + " field", jp.getCurrentLocation().getLineNr(),
// jp.getCurrentLocation().getColumnNr());
// }
// String fieldName = jp.getCurrentName();
//
// // move to the value token
// jp.nextToken();
//
// // set the appropriate state variable
// if (TYPE.equals(fieldName)) {
// type = jp.getText();
// }
// else if (XMLLANG.equals(fieldName)) {
// lang = jp.getText();
// }
// else if (DATATYPE.equals(fieldName)) {
// datatype = jp.getText();
// }
// else if (VALUE.equals(fieldName)) {
// value = jp.getText();
// }
// else {
// throw new QueryResultParseException("Unexpected field name: " + fieldName,
// jp.getCurrentLocation().getLineNr(),
// jp.getCurrentLocation().getColumnNr());
//
// }
// }
//
// nextBindingSet.addBinding(bindingStr, parseValue(type, value, lang, datatype));
/*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~ End Bigdata Changes ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
}
// parsing of solution finished, report result return to
// bindings state
if (!varsFound) {
// Buffer the bindings to fit with the
// QueryResultHandler contract so that startQueryResults
// is
// always called before handleSolution
bindings.add(nextBindingSet);
}
else if (handler != null) {
handler.handleSolution(nextBindingSet);
}
}
if (handler != null) {
handler.endQueryResult();
}
}
// Backwards compatibility with very old draft of the original
// SPARQL spec
else if (jp.getCurrentName().equals(DISTINCT) || jp.getCurrentName().equals(ORDERED)) {
jp.nextToken();
}
else {
throw new QueryResultParseException("Found unexpected field in results: "
+ jp.getCurrentName(), jp.getCurrentLocation().getLineNr(),
jp.getCurrentLocation().getColumnNr());
}
}
}
else if (baseStr.equals(BOOLEAN)) {
if (!attemptParseBoolean) {
throw new QueryResultParseException(
"Found boolean results when attempting to parse SPARQL Results JSON to tuple results");
}
jp.nextToken();
result = Boolean.parseBoolean(jp.getText());
if (handler != null) {
handler.handleBoolean(result);
}
}
else {
throw new QueryResultParseException("Found unexpected object in top level " + baseStr + " field",
jp.getCurrentLocation().getLineNr(), jp.getCurrentLocation().getColumnNr());
}
}
return result;
}
/**
* New method added to support Bigdata Sid extension.
*/
protected Value parseValue(final String bindingStr, final JsonParser jp)
throws QueryResultParseException, JsonParseException, IOException {
String lang = null;
String type = null;
String datatype = null;
String value = null;
while (jp.nextToken() != JsonToken.END_OBJECT) {
if (jp.getCurrentToken() != JsonToken.FIELD_NAME) {
throw new QueryResultParseException("Did not find value attribute under "
+ bindingStr + " field", jp.getCurrentLocation().getLineNr(),
jp.getCurrentLocation().getColumnNr());
}
String fieldName = jp.getCurrentName();
// move to the value token
jp.nextToken();
// set the appropriate state variable
if (TYPE.equals(fieldName)) {
type = jp.getText();
}
else if (XMLLANG.equals(fieldName)) {
lang = jp.getText();
}
else if (DATATYPE.equals(fieldName)) {
datatype = jp.getText();
}
else if (VALUE.equals(fieldName)) {
value = jp.getText();
}
else {
throw new QueryResultParseException("Unexpected field name: " + fieldName,
jp.getCurrentLocation().getLineNr(),
jp.getCurrentLocation().getColumnNr());
}
}
return parseValue(type, value, lang, datatype);
}
/**
* Parse a value out of the elements for a binding.
*
* @param type
* {@link #LITERAL}, {@link #TYPED_LITERAL}, {@link #BNODE} or
* {@link #URI}
* @param value
* actual value text
* @param language
* language tag, if applicable
* @param datatype
* datatype tag, if applicable
* @return the value corresponding to the given parameters
*/
protected Value parseValue(String type, String value, String language, String datatype) {
logger.trace("type: {}", type);
logger.trace("value: {}", value);
logger.trace("language: {}", language);
logger.trace("datatype: {}", datatype);
Value result = null;
if (type.equals(LITERAL) || type.equals(TYPED_LITERAL)) {
if (language != null) {
result = valueFactory.createLiteral(value, language);
}
else if (datatype != null) {
result = valueFactory.createLiteral(value, valueFactory.createURI(datatype));
}
else {
result = valueFactory.createLiteral(value);
}
}
else if (type.equals(BNODE)) {
result = valueFactory.createBNode(value);
}
else if (type.equals(URI)) {
result = valueFactory.createURI(value);
}
logger.debug("result value: {}", result);
return result;
}
}