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A SAX-based java RDFa parser.
/*
* (c) Copyright 2010 University of Bristol
* All rights reserved.
* [See end of file]
*/
package net.rootdev.javardfa.literal;
import java.io.StringWriter;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Stack;
import javax.xml.stream.XMLEventFactory;
import javax.xml.stream.XMLEventWriter;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.stream.events.Attribute;
import javax.xml.stream.events.StartElement;
import javax.xml.stream.events.XMLEvent;
import net.rootdev.javardfa.Parser;
/**
*
* @author pldms
*/
public class LiteralCollector {
final String XMLLiteral = "http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral";
private final Stack collectors;
private List queuedEvents;
private int level;
private final Parser parser;
private final StartElement fakeEnvelope;
private final XMLEventFactory eventFactory;
private final XMLOutputFactory outputFactory;
public LiteralCollector(Parser parser, XMLEventFactory eventFactory, XMLOutputFactory outputFactory) {
this.parser = parser;
this.collectors = new Stack();
this.queuedEvents = null;
this.eventFactory = eventFactory;
this.outputFactory = outputFactory;
this.fakeEnvelope = eventFactory.createStartElement("", null, "fake");
}
public boolean isCollecting() { return !collectors.isEmpty(); }
public boolean isCollectingXML() {
if (!isCollecting()) return false;
return XMLLiteral.equals(collectors.peek().datatype);
}
public void collect(String subject, Collection props, String datatype, String lang) {
if (!isCollecting()) { // set up collection
queuedEvents = new LinkedList();
level = 0;
}
Collector coll = new Collector(subject, props, datatype, lang, level, queuedEvents.size());
collectors.push(coll);
}
public void handleEvent(XMLEvent event) {
if (!isCollecting()) return; // nothing to do
if (event.isStartElement()) handleStartEvent(event);
else if (event.isEndElement()) handleEndEvent(event);
else queuedEvents.add(event);
}
private void handleStartEvent(XMLEvent event) {
level++;
queuedEvents.add(event);
if (collectors.peek().datatype == null) { // undecided so far
collectors.peek().datatype = XMLLiteral;
}
}
private void handleEndEvent(XMLEvent event) {
queuedEvents.add(event);
if (collectors.peek().level == level) {
Collector coll = collectors.pop();
emitTriples(coll, queuedEvents.subList(coll.start, queuedEvents.size()));
}
level--;
}
private void emitTriples(Collector coll, List subList) {
String lex = (XMLLiteral.equals(coll.datatype)) ?
gatherXML(subList, coll.lang) :
gatherText(subList) ;
if ((coll.datatype != null) && !"".equals(coll.datatype)) // not plain
parser.emitTriplesDatatypeLiteral(coll.subject,
coll.props, lex, coll.datatype);
else
parser.emitTriplesPlainLiteral(coll.subject,
coll.props, lex, coll.lang);
}
private String gatherXML(List subList, String lang) {
try {
return gatherXMLEx(subList, lang);
} catch (XMLStreamException ex) {
throw new RuntimeException("Problem gathering XML", ex);
}
}
private String gatherXMLEx(List subList, String lang)
throws XMLStreamException {
Attribute xmlLang = (lang == null) ?
null :
eventFactory.createAttribute("xml:lang", lang);
StringWriter sw = new StringWriter();
XMLStreamWriter out = outputFactory.createXMLStreamWriter(sw);
XMLEventWriter xmlWriter = new CanonicalXMLEventWriter(out, xmlLang);
xmlWriter.add(fakeEnvelope); // Some libraries dislike xml fragements
for (XMLEvent e: subList) {
xmlWriter.add(e);
}
xmlWriter.flush();
String xml = sw.toString();
return xml.substring(6, xml.length() - 7); // remove subList) {
StringBuilder sb = new StringBuilder();
for (XMLEvent e: subList) {
if (e.isCharacters()) sb.append(e.asCharacters().getData());
}
return sb.toString();
}
final static class Collector {
private final String subject;
private final Collection props;
private String datatype;
private final String lang;
private final int level;
private final int start;
private Collector(String subject, Collection props, String datatype,
String lang, int level, int start) {
this.subject = subject;
this.props = props;
this.datatype = datatype;
this.lang = lang;
this.level = level;
this.start = start;
}
}
}
/*
* (c) Copyright 2009 University of Bristol
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/