/**
* Copyright 2012 Martynas Jusevičius <martynas@graphity.org>
*
* Licensed 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.graphity.client.reader;
import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.rdf.model.RDFErrorHandler;
import com.hp.hpl.jena.rdf.model.RDFReader;
import com.hp.hpl.jena.shared.JenaException;
import com.hp.hpl.jena.util.FileUtils;
import java.io.*;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.net.URI;
import java.net.URL;
import java.net.URLConnection;
import javax.ws.rs.Consumes;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.*;
import javax.xml.transform.Source;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.URIResolver;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import org.graphity.server.provider.ModelProvider;
import org.graphity.client.util.XSLTBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Reads RDF from XML by transforming it to RDF/XML using GRDDL (XSLT) stylesheet
*
* @author Martynas Jusevičius <martynas@graphity.org>
* @see org.graphity.processor.locator.LocatorGRDDL
*/
@Consumes(MediaType.APPLICATION_XML)
public class ModelXSLTReader extends ModelProvider implements RDFReader
{
private static final Logger log = LoggerFactory.getLogger(ModelXSLTReader.class);
private Source stylesheet = null;
private URIResolver resolver = null;
protected RDFErrorHandler errorHandler = null ;
@Context private UriInfo uriInfo;
@Context private HttpHeaders httpHeaders;
/**
* Constructs from stylesheet source and URI resolver
*
* @param stylesheet the source of the XSLT transformation
* @param resolver URI resolver to be used in the transformation
* @see <a href="http://docs.oracle.com/javase/6/docs/api/javax/xml/transform/Source.html">Source</a>
* @see <a href="http://docs.oracle.com/javase/6/docs/api/javax/xml/transform/URIResolver.html">URIResolver</a>
*/
public ModelXSLTReader(Source stylesheet, URIResolver resolver)
{
if (stylesheet == null) throw new IllegalArgumentException("XSLT stylesheet Source cannot be null");
if (resolver == null) throw new IllegalArgumentException("URIResolver cannot be null");
this.stylesheet = stylesheet;
this.resolver = resolver;
}
@Override
public void read(Model model, Reader reader, String base)
{
throw new UnsupportedOperationException("Not supported yet.");
}
public void read(Model model, InputStream in, URI base)
{
Source doc = new StreamSource(in);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try
{
getXSLTBuilder(doc, base, baos).transform();
}
catch (TransformerConfigurationException ex)
{
if (log.isErrorEnabled()) log.error("Error in GRDDL XSLT transformer config", ex);
}
catch (TransformerException ex)
{
if (log.isErrorEnabled()) log.error("Error in GRDDL XSLT transformation", ex);
}
model.read(new BufferedInputStream(new ByteArrayInputStream(baos.toByteArray())), base.toString());
}
@Override
public void read(Model model, InputStream in, String base)
{
read(model, in, URI.create(base));
}
@Override
public void read(Model model, String url)
{
try {
URLConnection conn = new URL(url).openConnection();
String encoding = conn.getContentEncoding();
// Dispatch on MIME type.
// Inc .gz streams.
if ( encoding == null )
read(model, new InputStreamReader(conn.getInputStream(), FileUtils.encodingUTF8), url);
else
{
if ( ! encoding.equalsIgnoreCase("UTF-8") )
LoggerFactory.getLogger(this.getClass()).warn("URL content is not UTF-8") ;
read(model, new InputStreamReader(conn.getInputStream(),encoding), url);
}
}
catch (JenaException e)
{
if ( errorHandler == null )
throw e;
errorHandler.error(e) ;
}
catch (IOException ex)
{
if ( errorHandler == null ) throw new JenaException(ex) ;
errorHandler.error(ex) ;
}
}
@Override
public Object setProperty(String string, Object o)
{
return null;
}
@Override
public RDFErrorHandler setErrorHandler(RDFErrorHandler errHandler)
{
RDFErrorHandler old = errorHandler ;
errorHandler = errHandler ;
return old ;
}
@Override
public Model readFrom(Class<Model> type, Type genericType, Annotation[] annotations, javax.ws.rs.core.MediaType mediaType, MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException, WebApplicationException
{
if (log.isTraceEnabled()) log.trace("Reading model with HTTP headers: {} MediaType: {}", httpHeaders, mediaType);
Model model = ModelFactory.createDefaultModel();
read(model, entityStream, getUriInfo().getAbsolutePath()); // extract base URI from UriInfo?
return model;
}
public URIResolver getURIResolver()
{
return resolver;
}
public Source getStylesheet()
{
return stylesheet;
}
public UriInfo getUriInfo()
{
return uriInfo;
}
public HttpHeaders getHttpHeaders()
{
return httpHeaders;
}
public XSLTBuilder getXSLTBuilder(Source doc, URI base, OutputStream baos) throws TransformerConfigurationException
{
return XSLTBuilder.fromStylesheet(getStylesheet()).
resolver(getURIResolver()).
document(doc).
parameter("base-uri", base).
result(new StreamResult(baos));
}
}