/*
* Copyright (c) 2005, The Regents of the University of California, through
* Lawrence Berkeley National Laboratory (subject to receipt of any required
* approvals from the U.S. Dept. of Energy). 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) Neither the name of the University of California, Lawrence Berkeley
* National Laboratory, U.S. Dept. of Energy nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
* You are under no obligation whatsoever to provide any bug fixes, patches, or
* upgrades to the features, functionality or performance of the source code
* ("Enhancements") to anyone; however, if you choose to make your Enhancements
* available either publicly, or directly to Lawrence Berkeley National
* Laboratory, without imposing a separate written license agreement for such
* Enhancements, then you hereby grant the following license: a non-exclusive,
* royalty-free perpetual license to install, use, modify, prepare derivative
* works, incorporate into other computer software, distribute, and sublicense
* such enhancements or derivative works thereof, in binary and source code
* form.
*/
package nux.xom.pool;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.URIResolver;
import nu.xom.Document;
import nu.xom.NodeFactory;
import nu.xom.ParsingException;
import nu.xom.xslt.XSLException;
import nu.xom.xslt.XSLTransform;
/**
* Creates and returns new <code>XSLTransform</code> objects using flexible parametrization (thread-safe).
* TRAX factories, attributes and {@link URIResolver} of the underlying TRAX
* {@link TransformerFactory} can be specified by overriding the protected
* <code>getPreferredTransformerFactories</code> and <code>initFactory</code> methods.
* <p>
* For anything but simple/basic use cases, this API is more robust,
* configurable and convenient than the underlying XOM XSLTransform constructor API.
* <p>
* This implementation is thread-safe.
* <p>
* Example usage:
* <pre>
* // without custom factories:
* XSLTransform trans = new XSLTransformFactory().createTransform(new File("/tmp/test.xsl"));
* Document doc = BuilderPool.GLOBAL_POOL.getBuilder(false).build(new File("/tmp/test.xml"));
* Nodes nodes = trans.transform(doc);
* for (int i=0; i < nodes.size(); i++) {
* System.out.println("node "+i+": "+nodes.get(i).toXML());
* }
*
* // with custom factories:
* XSLTransformFactory factory = new XSLTransformFactory() {
* protected String[] getPreferredTransformerFactories() {
* return new String[] {
* "net.sf.saxon.TransformerFactoryImpl",
* "org.apache.xalan.processor.TransformerFactoryImpl"
* };
* }
* };
* XSLTransform trans = factory.createTransform(new File("/tmp/test.xsl"));
* Document doc = BuilderPool.GLOBAL_POOL.getBuilder(false).build(new File("/tmp/test.xml"));
* Nodes nodes = trans.transform(doc);
* </pre>
*
* @author whoschek.AT.lbl.DOT.gov
* @author $Author: hoschek3 $
* @version $Revision: 1.14 $, $Date: 2005/12/05 06:53:05 $
*/
public class XSLTransformFactory {
private static final String[] DEFAULT_TRAX_FACTORIES = {
"org.apache.xalan.processor.TransformerFactoryImpl", // slow but mostly correct
"com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl", // fast and mostly correct
"net.sf.saxon.TransformerFactoryImpl", // can do XSLT 2.0 and XQuery 1.0
"org.apache.xalan.xsltc.trax.TransformerFactoryImpl", // fast but buggy
"com.icl.saxon.TransformerFactoryImpl",
"oracle.xml.jaxp.JXSAXTransformerFactory",
"jd.xml.xslt.trax.TransformerFactoryImpl",
};
// A TRAX TransformerFactory is not thread-safe, so we use a ThreadLocal to make it thread-safe
private final ThreadLocal threadLocal;
private final DocumentFactory factory = new DocumentFactory();
private static final boolean DEBUG =
XOMUtil.getSystemProperty("nux.xom.pool.XSLTransformFactory.debug", false);
/**
* Creates a factory instance.
*/
public XSLTransformFactory() {
this.threadLocal = new SoftThreadLocal() {
protected Object initialSoftValue() { // lazy init
// find a TRAX factory that works
final String[] traxFactories = getPreferredTransformerFactories();
for (int i = 0; traxFactories != null && i < traxFactories.length; i++) {
// if (DEBUG) System.err.println("trying TRAX=" + traxFactories[i]);
try {
TransformerFactory factory = (TransformerFactory) ClassLoaderUtil.newInstance(traxFactories[i]);
initFactory(factory);
if (DEBUG) System.err.println("using TRAX TransformerFactory=" + factory.getClass().getName());
return factory;
} catch (ClassNotFoundException e) {
continue; // keep on trying
} catch (NoClassDefFoundError err) {
continue; // keep on trying
} catch (Throwable e) {
continue; // keep on trying
}
}
// try default TRAX initialization
// if (DEBUG) System.err.println("trying default TRAX");
TransformerFactory factory = TransformerFactory.newInstance();
initFactory(factory);
if (DEBUG) System.err.println("using default TRAX TransformerFactory=" + factory.getClass().getName());
return factory;
}
};
}
/**
* Creates and returns a new <code>XSLTransform</code> for the given stylesheet.
*
* @param stylesheet
* the stylesheet to compile
* @return an XSL transform
* @throws XSLException
* if the XSLTransform can't be created, e.g. because of an XSL syntax error.
*/
public XSLTransform createTransform(Document stylesheet) throws XSLException {
return newTransform(stylesheet, (TransformerFactory) threadLocal.get());
}
/**
* Creates and returns a new <code>XSLTransform</code> for the given stylesheet.
*
* @param stylesheet
* the stylesheet to compile
* @return an XSL transform
* @throws IOException
* if an I/O error occurs while reading from the stream
* @throws ParsingException
* if the stylesheet is not well-formed XML
* @throws XSLException
* if the XSLTransform can't be created, e.g. because of an XSL syntax error.
*/
public XSLTransform createTransform(File stylesheet) throws XSLException, ParsingException, IOException {
return createTransform(factory.createDocument(stylesheet));
}
/**
* Creates and returns a new <code>XSLTransform</code> for the given stylesheet.
*
* @param stylesheet
* the stylesheet to compile
* @param baseURI
* the (absolute) baseURI of the stylesheet (may be <code>null</code>)
* Need not be the stream's actual URI.
* @return an XSL transform
* @throws IOException
* if an I/O error occurs while reading from the stream
* @throws ParsingException
* if the stylesheet is not well-formed XML
* @throws XSLException
* if the XSLTransform can't be created, e.g. because of an XSL syntax error.
*/
public XSLTransform createTransform(InputStream stylesheet, URI baseURI) throws XSLException, ParsingException, IOException {
return createTransform(factory.createDocument(stylesheet, baseURI));
}
/**
* Callback that creates and returns a new <code>XSLTransform</code> for the given
* stylesheet and TransformerFactory.
* <p>
* Override this method if you want to create custom subclasses of XSLTransform.
*
* @param stylesheet
* the stylesheet to compile
* @param transformerFactory
* the TransformerFactory
* @return an XSL transform
* @throws XSLException
* if no XSLTransform can be obtained for the given stylesheet;
* in particular when the supplied stylesheet is not
* syntactically correct XSLT
*/
protected XSLTransform newTransform(Document stylesheet, TransformerFactory transformerFactory) throws XSLException {
return new XSLTransform(stylesheet, new NodeFactory(), transformerFactory);
}
/**
* Callback that returns a search list of fully qualified class names of TRAX
* {@link TransformerFactory} implementations, given in order of
* preference from left to right. May return <code>null</code>.
* <p>
* Override this method for custom behaviour.
* This default implementation returns a search list for the most popular
* TRAX implementations.
*
* @return a search list
*/
protected String[] getPreferredTransformerFactories() {
return DEFAULT_TRAX_FACTORIES;
}
/**
* Callback that initializes the supplied TransformerFactory with
* application-specific attributes and a URIResolver, if so desired.
* <p>
* Override this method if you need custom attributes/resolvers. This
* default implementation does nothing.
* <p>
* Note: Attributes and resolver are not part of the constructor because
* they may well be stateful and mutable, hence it may well be unsafe to
* share them among multiple XSLTransforms in a multi-threaded context. By
* providing this method, an application can create attributes/resolvers as
* needed via straightforward subclassing/overriding of this method.
*
* @param factory
* the factory to initialize
*/
protected void initFactory(TransformerFactory factory) {
}
}