/**
* Copyright 2005-2014 Restlet
*
* The contents of this file are subject to the terms of one of the following
* open source licenses: Apache 2.0 or or EPL 1.0 (the "Licenses"). You can
* select the license that you prefer but you may not use this file except in
* compliance with one of these Licenses.
*
* You can obtain a copy of the Apache 2.0 license at
* http://www.opensource.org/licenses/apache-2.0
*
* You can obtain a copy of the EPL 1.0 license at
* http://www.opensource.org/licenses/eclipse-1.0
*
* See the Licenses for the specific language governing permissions and
* limitations under the Licenses.
*
* Alternatively, you can obtain a royalty free commercial license with less
* limitations, transferable or non-transferable, directly at
* http://restlet.com/products/restlet-framework
*
* Restlet is a registered trademark of Restlet S.A.S.
*/
package org.restlet.ext.xml;
import java.io.IOException;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;
import javax.xml.transform.ErrorListener;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Templates;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.URIResolver;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import org.restlet.Context;
import org.restlet.ext.xml.internal.AbstractXmlReader;
import org.restlet.ext.xml.internal.ContextResolver;
import org.restlet.representation.Representation;
import org.restlet.representation.WriterRepresentation;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLFilter;
import org.xml.sax.XMLReader;
/**
* Representation able to apply an XSLT transformation. The internal JAXP
* transformer is created when the getTransformer() method is first called. So,
* if you need to specify a custom URI resolver, do it before actually using the
* representation for a transformation.<br>
* <br>
* This representation should be viewed as a wrapper representation that applies
* a transform sheet on a source representation when it is read or written out.
* Therefore, it isn't intended to be reused on different sources. For this use
* case, you should instead use the {@link org.restlet.routing.Transformer}
* filter.
*
* @author Jerome Louvel
*/
public class TransformRepresentation extends WriterRepresentation {
/**
* Wraps a source representation into a {@link SAXSource}. This method can
* detect other {@link XmlRepresentation} instances to use their
* {@link XmlRepresentation#getSaxSource()} method as well as other
* {@link TransformRepresentation} instances to support transformation
* chaining.
*
* @param representation
* The source representation.
* @return The SAX source.
* @throws IOException
*/
public static SAXSource toSaxSource(Representation representation)
throws IOException {
SAXSource result = null;
if (representation instanceof XmlRepresentation) {
result = ((XmlRepresentation) representation).getSaxSource();
} else if (representation instanceof TransformRepresentation) {
final TransformRepresentation source = (TransformRepresentation) representation;
XMLReader reader = new AbstractXmlReader() {
/**
* Parses the input source by sending the result event to the
* XML reader's content handler.
*
* @param input
* The input source.
*/
public void parse(InputSource input) throws IOException,
SAXException {
try {
source.getTransformer().transform(
source.getSaxSource(),
new SAXResult(getContentHandler()));
} catch (TransformerException te) {
throw new IOException("Transformer exception. "
+ te.getMessage());
}
}
public void parse(String systemId) throws IOException,
SAXException {
throw new IllegalStateException("Not implemented");
}
};
result = new SAXSource(reader, new InputSource(
representation.getReader()));
} else {
// Prepare the source and result documents
result = new SAXSource(new InputSource(representation.getReader()));
}
// Copy the representation's URI as an XML system ID.
if (representation.getLocationRef() != null) {
result.setSystemId(representation.getLocationRef().getTargetRef()
.toString());
}
return result;
}
/** The transformer's error listener. */
private volatile ErrorListener errorListener;
/** The JAXP transformer output properties. */
private volatile Map<String, String> outputProperties;
/** The JAXP transformer parameters. */
private volatile Map<String, Object> parameters;
/** The source representation to transform. */
private volatile Representation sourceRepresentation;
/** The template to be used and reused. */
private volatile Templates templates;
/** The XSLT transform sheet to apply to message entities. */
private volatile Representation transformSheet;
/** The URI resolver. */
private volatile URIResolver uriResolver;
/**
* Constructor. Note that a default URI resolver will be created based on
* the given context.
*
* @param context
* The parent context.
* @param source
* The source representation to transform.
* @param transformSheet
* The XSLT transform sheet to apply.
*/
public TransformRepresentation(Context context, Representation source,
Representation transformSheet) {
this((context == null) ? null : new ContextResolver(context), source,
transformSheet);
}
/**
* Default constructor.
*
* @param source
* The source representation to transform.
* @param transformSheet
* The XSLT transform sheet to apply.
*/
public TransformRepresentation(Representation source,
Representation transformSheet) {
this((URIResolver) null, source, transformSheet);
}
/**
* Constructor. Note that a default URI resolver will be created based on
* the given context.
*
* @param uriResolver
* The JAXP URI resolver.
* @param source
* The source representation to transform.
* @param transformSheet
* The XSLT transform sheet to apply.
*/
public TransformRepresentation(URIResolver uriResolver,
Representation source, Representation transformSheet) {
this(uriResolver, source, transformSheet, null);
}
/**
* Constructor.
*
* @param uriResolver
* The optional JAXP URI resolver.
* @param source
* The source representation to transform.
* @param templates
* The precompiled JAXP template.
*/
private TransformRepresentation(URIResolver uriResolver,
Representation source, Representation transformSheet,
Templates templates) {
super(null);
this.sourceRepresentation = source;
this.templates = templates;
this.transformSheet = transformSheet;
this.uriResolver = uriResolver;
this.parameters = new HashMap<String, Object>();
this.outputProperties = new HashMap<String, String>();
this.errorListener = null;
}
/**
* Constructor.
*
* @param uriResolver
* The optional JAXP URI resolver.
* @param source
* The source representation to transform.
* @param templates
* The precompiled JAXP template.
*/
public TransformRepresentation(URIResolver uriResolver,
Representation source, Templates templates) {
this(uriResolver, source, null, templates);
}
/**
* Returns the transformer's error listener. Default value is null, leaving
* the original listener intact.
*
* @return The transformer's error listener.
*/
public ErrorListener getErrorListener() {
return errorListener;
}
/**
* Returns the modifiable map of JAXP transformer output properties.
*
* @return The JAXP transformer output properties.
*/
public Map<String, String> getOutputProperties() {
return this.outputProperties;
}
/**
* Returns the modifiable map of JAXP transformer parameters.
*
* @return The JAXP transformer parameters.
*/
public Map<String, Object> getParameters() {
return this.parameters;
}
/**
* Returns the SAX source associated to the source representation.
*
* @return The SAX source associated to the source representation.
* @throws IOException
*/
public SAXSource getSaxSource() throws IOException {
return toSaxSource(getSourceRepresentation());
}
/**
* Returns the default SAX transformer factory.
*
* @return The default SAX transformer factory.
*/
private SAXTransformerFactory getSaxTransformerFactory() {
SAXTransformerFactory result = (SAXTransformerFactory) TransformerFactory
.newInstance();
return result;
}
/**
* Returns the source representation to transform.
*
* @return The source representation to transform.
*/
public Representation getSourceRepresentation() {
return this.sourceRepresentation;
}
/**
* Returns the templates to be used and reused. If no one exists, it creates
* a new one based on the transformSheet representation and on the URI
* resolver.
*
* @return The templates to be used and reused.
*/
public Templates getTemplates() throws IOException {
if (this.templates == null) {
if (getTransformSheet() != null) {
try {
// Prepare the XSLT transformer documents
final StreamSource transformSource = new StreamSource(
getTransformSheet().getStream());
if (getTransformSheet().getLocationRef() != null) {
transformSource.setSystemId(getTransformSheet()
.getLocationRef().getTargetRef().toString());
}
// Create the transformer factory
final TransformerFactory transformerFactory = TransformerFactory
.newInstance();
// Set the URI resolver
if (getUriResolver() != null) {
transformerFactory.setURIResolver(getUriResolver());
}
// Create a new transformer
this.templates = transformerFactory
.newTemplates(transformSource);
} catch (TransformerConfigurationException tce) {
throw new IOException(
"Transformer configuration exception. "
+ tce.getMessage());
}
}
}
return this.templates;
}
/**
* Returns a new transformer to be used. Creation is based on the
* {@link #getTemplates()}.newTransformer() method.
*
* @return The new transformer to be used.
*/
public Transformer getTransformer() throws IOException {
Transformer result = null;
try {
Templates templates = getTemplates();
if (templates != null) {
result = templates.newTransformer();
if (getErrorListener() != null) {
result.setErrorListener(getErrorListener());
}
if (getUriResolver() != null) {
result.setURIResolver(getUriResolver());
}
for (String name : getParameters().keySet()) {
result.setParameter(name, getParameters().get(name));
}
for (String name : getOutputProperties().keySet()) {
result.setOutputProperty(name,
getOutputProperties().get(name));
}
}
} catch (TransformerConfigurationException tce) {
throw new IOException("Transformer configuration exception. "
+ tce.getMessage());
} catch (TransformerFactoryConfigurationError tfce) {
throw new IOException(
"Transformer factory configuration exception. "
+ tfce.getMessage());
}
return result;
}
/**
* Returns the SAX transformer handler associated to the transform sheet.
*
* @return The SAX transformer handler.
* @throws IOException
*/
public TransformerHandler getTransformerHandler() throws IOException {
TransformerHandler result = null;
Templates templates = getTemplates();
if (templates != null) {
try {
result = getSaxTransformerFactory().newTransformerHandler(
templates);
} catch (TransformerConfigurationException tce) {
throw new IOException("Transformer configuration exception. "
+ tce.getMessage());
}
}
return result;
}
/**
* Returns the XSLT transform sheet to apply to the source representation.
*
* @return The XSLT transform sheet to apply.
*/
public Representation getTransformSheet() {
return this.transformSheet;
}
/**
* Returns the URI resolver.
*
* @return The URI resolver.
*/
public URIResolver getUriResolver() {
return this.uriResolver;
}
/**
* Returns the SAX XML filter applying the transform sheet to its input.
*
* @return The SAX XML filter.
* @throws IOException
*/
public XMLFilter getXmlFilter() throws IOException {
XMLFilter result = null;
final Templates templates = getTemplates();
if (templates != null) {
try {
result = getSaxTransformerFactory().newXMLFilter(templates);
} catch (TransformerConfigurationException tce) {
throw new IOException("Transformer configuration exception. "
+ tce.getMessage());
}
}
return result;
}
/**
* Releases the source and transform sheet representations, the transformer
* and the URI resolver.
*/
@Override
public void release() {
if (this.sourceRepresentation != null) {
this.sourceRepresentation.release();
this.sourceRepresentation = null;
}
if (this.templates != null) {
this.templates = null;
}
if (this.transformSheet != null) {
this.transformSheet.release();
this.transformSheet = null;
}
if (this.uriResolver != null) {
this.uriResolver = null;
}
super.release();
}
/**
* Sets the transformer's error listener.
*
* @param errorListener
* The transformer's error listener.
*/
public void setErrorListener(ErrorListener errorListener) {
this.errorListener = errorListener;
}
/**
* Sets the modifiable map of JAXP transformer output properties.
*
* @param outputProperties
* The JAXP transformer output properties.
*/
public void setOutputProperties(Map<String, String> outputProperties) {
this.outputProperties = outputProperties;
}
/**
* Sets the JAXP transformer parameters.
*
* @param parameters
* The JAXP transformer parameters.
*/
public void setParameters(Map<String, Object> parameters) {
this.parameters = parameters;
}
/**
* Sets the source representation to transform.
*
* @param source
* The source representation to transform.
*/
public void setSourceRepresentation(Representation source) {
this.sourceRepresentation = source;
}
/**
* Sets the templates to be used and reused.
*
* @param templates
* The templates to be used and reused.
*/
public void setTemplates(Templates templates) {
this.templates = templates;
}
/**
* Sets the XSLT transform sheet to apply to message entities.
*
* @param transformSheet
* The XSLT transform sheet to apply to message entities.
*/
public void setTransformSheet(Representation transformSheet) {
this.transformSheet = transformSheet;
}
/**
* Sets the URI resolver.
*
* @param uriResolver
* The URI resolver.
*/
public void setUriResolver(URIResolver uriResolver) {
this.uriResolver = uriResolver;
}
/**
* Transforms the given JAXP source into the given result.
*
* @param source
* The JAXP source object.
* @param result
* The JAXP result object.
* @throws IOException
*/
public void transform(Source source, Result result) throws IOException {
if (getTransformer() == null) {
Context.getCurrentLogger()
.warning(
"Unable to apply the transformation. No transformer found!");
} else {
try {
// Generates the result of the transformation
getTransformer().transform(source, result);
} catch (TransformerException te) {
throw new IOException("Transformer exception. "
+ te.getMessage());
}
}
}
/**
* Writes the transformed source into the given JAXP result. The source is
* retrieved using the {@link #getSaxSource()} method.
*
* @param result
* The JAXP result object.
* @throws IOException
*/
public void write(Result result) throws IOException {
transform(getSaxSource(), result);
}
/**
* Writes the transformed source into the given output stream. By default,
* it leverages the {@link #write(Result)} method using a
* {@link StreamResult} object.
*/
@Override
public void write(Writer writer) throws IOException {
write(new StreamResult(writer));
}
}