/*
* Copyright Aduna (http://www.aduna-software.com/) (c) 1997-2007.
*
* Licensed under the Aduna BSD-style license.
*/
package org.openrdf.rio.trix;
import static org.openrdf.rio.trix.TriXConstants.BNODE_TAG;
import static org.openrdf.rio.trix.TriXConstants.CONTEXT_TAG;
import static org.openrdf.rio.trix.TriXConstants.DATATYPE_ATT;
import static org.openrdf.rio.trix.TriXConstants.LANGUAGE_ATT;
import static org.openrdf.rio.trix.TriXConstants.PLAIN_LITERAL_TAG;
import static org.openrdf.rio.trix.TriXConstants.TRIPLE_TAG;
import static org.openrdf.rio.trix.TriXConstants.TYPED_LITERAL_TAG;
import static org.openrdf.rio.trix.TriXConstants.URI_TAG;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import org.xml.sax.SAXException;
import info.aduna.xml.SimpleSAXAdapter;
import info.aduna.xml.SimpleSAXParser;
import org.openrdf.model.Resource;
import org.openrdf.model.Statement;
import org.openrdf.model.URI;
import org.openrdf.model.Value;
import org.openrdf.model.ValueFactory;
import org.openrdf.model.impl.ValueFactoryImpl;
import org.openrdf.rio.RDFFormat;
import org.openrdf.rio.RDFHandlerException;
import org.openrdf.rio.RDFParseException;
import org.openrdf.rio.helpers.RDFParserBase;
/**
* A parser that can parse RDF files that are in the <a
* href="http://www.w3.org/2004/03/trix/">TriX format</a>.
*
* @author Arjohn Kampman
*/
public class TriXParser extends RDFParserBase {
/*--------------*
* Constructors *
*--------------*/
/**
* Creates a new TriXParser that will use a {@link ValueFactoryImpl} to
* create objects for resources, bNodes, literals and statements.
*/
public TriXParser() {
super();
}
/**
* Creates a new TriXParser that will use the supplied ValueFactory to create
* objects for resources, bNodes, literals and statements.
*
* @param valueFactory
* A ValueFactory.
*/
public TriXParser(ValueFactory valueFactory) {
super(valueFactory);
}
/*---------*
* Methods *
*---------*/
public final RDFFormat getRDFFormat() {
return RDFFormat.TRIX;
}
public void parse(InputStream in, String baseURI)
throws IOException, RDFParseException, RDFHandlerException
{
parse(in);
}
public void parse(Reader reader, String baseURI)
throws IOException, RDFParseException, RDFHandlerException
{
parse(reader);
}
private void parse(Object inputStreamOrReader)
throws IOException, RDFParseException, RDFHandlerException
{
try {
rdfHandler.startRDF();
SimpleSAXParser saxParser = new SimpleSAXParser();
saxParser.setPreserveWhitespace(true);
saxParser.setListener(new TriXSAXHandler());
if (inputStreamOrReader instanceof InputStream) {
saxParser.parse((InputStream)inputStreamOrReader);
}
else {
saxParser.parse((Reader)inputStreamOrReader);
}
rdfHandler.endRDF();
}
catch (SAXException e) {
Exception wrappedExc = e.getException();
if (wrappedExc instanceof RDFParseException) {
throw (RDFParseException)wrappedExc;
}
else if (wrappedExc instanceof RDFHandlerException) {
throw (RDFHandlerException)wrappedExc;
}
else {
reportFatalError(wrappedExc);
}
}
}
/*----------------------------*
* Inner class TriXSAXHandler *
*----------------------------*/
private class TriXSAXHandler extends SimpleSAXAdapter {
private Resource currentContext;
private boolean parsingContext;
private List<Value> valueList;
public TriXSAXHandler() {
currentContext = null;
valueList = new ArrayList<Value>(3);
}
@Override
public void startTag(String tagName, Map<String, String> atts, String text)
throws SAXException
{
try {
if (tagName.equals(URI_TAG)) {
valueList.add(createURI(text));
}
else if (tagName.equals(BNODE_TAG)) {
valueList.add(createBNode(text));
}
else if (tagName.equals(PLAIN_LITERAL_TAG)) {
String lang = atts.get(LANGUAGE_ATT);
valueList.add(createLiteral(text, lang, null));
}
else if (tagName.equals(TYPED_LITERAL_TAG)) {
String datatype = atts.get(DATATYPE_ATT);
if (datatype == null) {
reportError(DATATYPE_ATT + " attribute missing for typed literal");
valueList.add(createLiteral(text, null, null));
}
else {
URI dtURI = createURI(datatype);
valueList.add(createLiteral(text, null, dtURI));
}
}
else if (tagName.equals(TRIPLE_TAG)) {
if (parsingContext) {
try {
// First triple in a context, valueList can contain
// context information
if (valueList.size() > 1) {
reportError("At most 1 resource can be specified for the context");
}
else if (valueList.size() == 1) {
try {
currentContext = (Resource)valueList.get(0);
}
catch (ClassCastException e) {
reportError("Context identifier should be a URI or blank node");
}
}
}
finally {
parsingContext = false;
valueList.clear();
}
}
}
else if (tagName.equals(CONTEXT_TAG)) {
parsingContext = true;
}
}
catch (RDFParseException e) {
throw new SAXException(e);
}
}
@Override
public void endTag(String tagName)
throws SAXException
{
try {
if (tagName.equals(TRIPLE_TAG)) {
reportStatement();
}
else if (tagName.equals(CONTEXT_TAG)) {
currentContext = null;
}
}
catch (RDFParseException e) {
throw new SAXException(e);
}
catch (RDFHandlerException e) {
throw new SAXException(e);
}
}
private void reportStatement()
throws RDFParseException, RDFHandlerException
{
try {
if (valueList.size() != 3) {
reportError("exactly 3 values are required for a triple");
return;
}
Resource subj;
URI pred;
Value obj;
try {
subj = (Resource)valueList.get(0);
}
catch (ClassCastException e) {
reportError("First value for a triple should be a URI or blank node");
return;
}
try {
pred = (URI)valueList.get(1);
}
catch (ClassCastException e) {
reportError("Second value for a triple should be a URI");
return;
}
obj = valueList.get(2);
Statement st = createStatement(subj, pred, obj, currentContext);
rdfHandler.handleStatement(st);
}
finally {
valueList.clear();
}
}
} // end inner class TriXSAXHandler
}