/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* 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.apache.cocoon.components.xslt;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import javax.xml.transform.Result;
import javax.xml.transform.Templates;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.URIResolver;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TemplatesHandler;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamSource;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.component.ComponentException;
import org.apache.avalon.framework.component.ComponentManager;
import org.apache.avalon.framework.component.Composable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.parameters.ParameterException;
import org.apache.avalon.framework.parameters.Parameterizable;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.util.ClassUtils;
import org.apache.cocoon.util.TraxErrorHandler;
import org.apache.excalibur.source.Source;
import org.apache.excalibur.source.SourceException;
import org.apache.excalibur.source.SourceResolver;
import org.apache.excalibur.store.Store;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.XMLFilter;
/**
* This class defines the implementation of the {@link XSLTProcessor}
* component.
*
* To configure it, add the following lines in the
* <file>cocoon.xconf</file> file:
*
* <pre>
* <xslt-processor class="org.apache.cocoon.components.xslt.XSLTProcessorImpl">
* <parameter name="use-store" value="true"/>
* <parameter name="transformer-factory" value="org.apache.xalan.processor.TransformerFactoryImpl"/>
* </xslt-processor>
* </pre>
*
* The <use-store> configuration forces the transformer to put the
* <code>Templates</code> generated from the XSLT stylesheet into the
* <code>Store</code>. This property is true by default.
* <p>
* The <transformer-factory> configuration tells the transformer to use a particular
* implementation of <code>javax.xml.transform.TransformerFactory</code>. This allows to force
* the use of a given TRAX implementation (e.g. xalan or saxon) if several are available in the
* classpath. If this property is not set, the transformer uses the standard TRAX mechanism
* (<code>TransformerFactory.newInstance()</code>).
*
* @deprecated Use the avalon excalibur xslt processor instead.
* @author <a href="mailto:ovidiu@cup.hp.com">Ovidiu Predescu</a>
* @author <a href="mailto:stefano@apache.org">Stefano Mazzocchi</a>
* @version CVS $Id: XSLTProcessorImpl.java,v 1.4 2004/03/05 13:02:41 bdelacretaz Exp $
* @version 1.0
* @since July 11, 2001
*/
public class XSLTProcessorImpl
extends AbstractLogEnabled
implements XSLTProcessor,
Composable,
Disposable,
Parameterizable,
URIResolver {
protected ComponentManager manager;
/** The store service instance */
protected Store store;
/** The trax TransformerFactory lookup table*/
protected HashMap factories;
/** The trax TransformerFactory this component uses */
protected SAXTransformerFactory factory;
/** Is the store turned on? (default is on) */
protected boolean useStore = true;
/** Is incremental processing turned on? (default for Xalan: no) */
protected boolean incrementalProcessing = false;
/** The source resolver used by this processor **/
protected SourceResolver resolver;
/** The error handler for the transformer */
protected TraxErrorHandler errorHandler;
/**
* Compose. Try to get the store
*/
public void compose(ComponentManager manager)
throws ComponentException {
this.manager = manager;
if (this.getLogger().isDebugEnabled())
this.getLogger().debug("XSLTProcessorImpl component initialized.");
this.store = (Store) manager.lookup(Store.TRANSIENT_STORE);
this.errorHandler = new TraxErrorHandler( this.getLogger() );
this.resolver = (SourceResolver) manager.lookup(SourceResolver.ROLE);
}
/**
* Dispose
*/
public void dispose() {
if (this.manager != null) {
this.manager.release(this.store);
this.store = null;
this.manager.release(this.resolver);
this.resolver = null;
}
this.errorHandler = null;
this.manager = null;
}
/**
* Configure the component
*/
public void parameterize(Parameters params)
throws ParameterException {
this.useStore = params.getParameterAsBoolean("use-store", true);
this.incrementalProcessing = params.getParameterAsBoolean("incremental-processing", false);
this.factory = getTransformerFactory(params.getParameter("transformer-factory", DEFAULT_FACTORY));
}
/**
* Set the source resolver used by this component
* @deprecated The processor can now simply lookup the source resolver.
*/
public void setSourceResolver(org.apache.cocoon.environment.SourceResolver resolver) {
if (this.getLogger().isDebugEnabled()) {
this.getLogger().debug("XSLTProcessor: the setSourceResolver() method is deprecated.");
}
}
/**
* Set the transformer factory used by this component
*/
public void setTransformerFactory(String classname) {
this.factory = getTransformerFactory(classname);
}
public TransformerHandler getTransformerHandler(org.apache.cocoon.environment.Source stylesheet)
throws ProcessingException {
return getTransformerHandler(stylesheet, null);
}
public TransformerHandler getTransformerHandler(org.apache.cocoon.environment.Source stylesheet,
XMLFilter filter)
throws ProcessingException {
try {
final String id = stylesheet.getSystemId();
Templates templates = getTemplates(stylesheet, id);
if (templates == null) {
if (this.getLogger().isDebugEnabled()) {
getLogger().debug("Creating new Templates for " + id);
}
// Create a Templates ContentHandler to handle parsing of the
// stylesheet.
TemplatesHandler templatesHandler = this.factory.newTemplatesHandler();
// Set the system ID for the template handler since some
// TrAX implementations (XSLTC) rely on this in order to obtain
// a meaningful identifier for the Templates instances.
templatesHandler.setSystemId(id);
if (filter != null) {
filter.setContentHandler(templatesHandler);
}
if (this.getLogger().isDebugEnabled()) {
getLogger().debug("Source = " + stylesheet
+ ", templatesHandler = " + templatesHandler);
}
// Process the stylesheet.
stylesheet.toSAX(filter != null ?
(ContentHandler)filter : (ContentHandler)templatesHandler);
// Get the Templates object (generated during the parsing of
// the stylesheet) from the TemplatesHandler.
templates = templatesHandler.getTemplates();
putTemplates (templates, stylesheet, id);
} else {
if (this.getLogger().isDebugEnabled()) {
getLogger().debug("Reusing Templates for " + id);
}
}
TransformerHandler handler = this.factory.newTransformerHandler(templates);
handler.getTransformer().setErrorListener(this.errorHandler);
handler.getTransformer().setURIResolver(this);
return handler;
} catch (ProcessingException e) {
throw e;
} catch (SAXException e) {
if (e.getException() == null) {
throw new ProcessingException("Exception in creating Transform Handler", e);
} else {
if (getLogger().isDebugEnabled())
getLogger().debug("Got SAXException. Rethrowing cause exception.", e);
throw new ProcessingException("Exception in creating Transform Handler", e.getException());
}
} catch (Exception e) {
throw new ProcessingException("Exception in creating Transform Handler", e);
}
}
public void transform(org.apache.cocoon.environment.Source source,
org.apache.cocoon.environment.Source stylesheet,
Parameters params,
Result result)
throws ProcessingException {
try {
if (this.getLogger().isDebugEnabled()) {
getLogger().debug("XSLTProcessorImpl: transform source = " + source
+ ", stylesheet = " + stylesheet
+ ", parameters = " + params
+ ", result = " + result);
}
TransformerHandler handler = getTransformerHandler(stylesheet);
Transformer transformer = handler.getTransformer();
if (params != null) {
transformer.clearParameters();
String[] names = params.getNames();
for (int i = names.length -1 ; i >= 0; i--) {
transformer.setParameter(names[i], params.getParameter(names[i]));
}
}
if (getLogger().isDebugEnabled())
this.getLogger().debug("XSLTProcessorImpl: starting transform");
// Is it possible to use Source's toSAX method?
handler.setResult(result);
source.toSAX(handler);
if (getLogger().isDebugEnabled())
this.getLogger().debug("XSLTProcessorImpl: transform done");
} catch (Exception e) {
throw new ProcessingException("Error in running Transformation", e);
}
}
/**
* Get the TransformerFactory associated with the given classname. If
* the class can't be found or the given class doesn't implement
* the required interface, the default factory is returned.
*/
private SAXTransformerFactory getTransformerFactory(String factoryName) {
SAXTransformerFactory _factory;
if ((factoryName == null) || (factoryName == XSLTProcessor.DEFAULT_FACTORY)) {
_factory = (SAXTransformerFactory) TransformerFactory.newInstance();
} else {
try {
_factory = (SAXTransformerFactory) ClassUtils.loadClass(factoryName).newInstance();
} catch (ClassNotFoundException cnfe) {
if (getLogger().isErrorEnabled())
getLogger().error("Cannot find the requested TrAX factory '" + factoryName
+ "'. Using default TrAX Transformer Factory instead.");
if (this.factory != null) return this.factory;
_factory = (SAXTransformerFactory) TransformerFactory.newInstance();
} catch (ClassCastException cce) {
if (getLogger().isErrorEnabled())
getLogger().error("The indicated class '" + factoryName
+ "' is not a TrAX Transformer Factory. Using default TrAX Transformer Factory instead.");
if (this.factory != null) return this.factory;
_factory = (SAXTransformerFactory) TransformerFactory.newInstance();
} catch (Exception e) {
if (getLogger().isErrorEnabled())
getLogger().error("Error found loading the requested TrAX Transformer Factory '"
+ factoryName + "'. Using default TrAX Transformer Factory instead.");
if (this.factory != null) return this.factory;
_factory = (SAXTransformerFactory) TransformerFactory.newInstance();
}
}
_factory.setErrorListener(this.errorHandler);
_factory.setURIResolver(this);
// implementation-specific parameter passing should be
// made more extensible.
if (_factory.getClass().getName().equals("org.apache.xalan.processor.TransformerFactoryImpl")) {
_factory.setAttribute("http://xml.apache.org/xalan/features/incremental",
new Boolean (incrementalProcessing));
}
return _factory;
}
private Templates getTemplates(org.apache.cocoon.environment.Source stylesheet,
String id)
throws IOException, ProcessingException {
if (!useStore) {
return null;
}
// we must augment the template ID with the factory classname since one
// transformer implementation cannot handle the instances of a
// template created by another one.
id += factory.getClass().getName();
Templates templates = null;
// only stylesheets with a last modification date are stored
if (stylesheet.getLastModified() != 0) {
// Stored is an array of the template and the caching time
if (store.containsKey(id)) {
Object[] templateAndTime = (Object[])store.get(id);
if(templateAndTime != null && templateAndTime[1] != null) {
long storedTime = ((Long)templateAndTime[1]).longValue();
if (storedTime < stylesheet.getLastModified()) {
store.remove(id);
} else {
templates = (Templates)templateAndTime[0];
}
}
}
} else if (store.containsKey(id)) {
// remove an old template if it exists
store.remove(id);
}
return templates;
}
private void putTemplates (Templates templates, org.apache.cocoon.environment.Source stylesheet,
String id)
throws IOException, ProcessingException {
if (!useStore) {
return;
}
// we must augment the template ID with the factory classname since one
// transformer implementation cannot handle the instances of a
// template created by another one.
id += factory.getClass().getName();
// only stylesheets with a last modification date are stored
if (stylesheet.getLastModified() != 0) {
// Stored is an array of the template and the current time
Object[] templateAndTime = new Object[2];
templateAndTime[0] = templates;
templateAndTime[1] = new Long(stylesheet.getLastModified());
store.store(id, templateAndTime);
}
}
/**
* Called by the processor when it encounters
* an xsl:include, xsl:import, or document() function.
*
* @param href An href attribute, which may be relative or absolute.
* @param base The base URI in effect when the href attribute
* was encountered.
*
* @return A Source object, or null if the href cannot be resolved,
* and the processor should try to resolve the URI itself.
*
* @throws TransformerException if an error occurs when trying to
* resolve the URI.
*/
public javax.xml.transform.Source resolve(String href, String base)
throws TransformerException {
if (this.getLogger().isDebugEnabled()) {
this.getLogger().debug("resolve(href = " + href +
", base = " + base + "); resolver = " + resolver);
}
Source xslSource = null;
try {
if (href.indexOf(":") > 1) {
xslSource = resolver.resolveURI(href);
} else {
// patch for a null pointer passed as base
if (base == null)
throw new IllegalArgumentException("Null pointer passed as base");
// is the base a file or a real url
if (!base.startsWith("file:")) {
int lastPathElementPos = base.lastIndexOf('/');
if (lastPathElementPos == -1) {
// this should never occur as the base should
// always be protocol:/....
return null; // we can't resolve this
} else {
xslSource = resolver.resolveURI(new StringBuffer(base.substring(0, lastPathElementPos))
.append("/").append(href).toString());
}
} else {
File parent = new File(base.substring(5));
File parent2 = new File(parent.getParentFile(), href);
xslSource = resolver.resolveURI(parent2.toURL().toExternalForm());
}
}
if (this.getLogger().isDebugEnabled()) {
getLogger().debug("xslSource = " + xslSource
+ ", system id = " + xslSource.getURI());
}
return new StreamSource(xslSource.getInputStream(), xslSource.getURI());
} catch (java.net.MalformedURLException mue) {
return null;
} catch (SourceException pe) {
throw new TransformerException(pe);
} catch (IOException ioe) {
return null;
} finally {
this.resolver.release( xslSource );
}
}
}