de.tbuchloh.kiskis.persistence.exporter.XMLTransformer.java Source code

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Here is the source code for de.tbuchloh.kiskis.persistence.exporter.XMLTransformer.java

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/*
 * Copyright (C) 2004 by Tobias Buchloh.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this program; if not, write to the Free
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * If you didn't download this code from the following link, you should check if
 * you aren't using an obsolete version:
 * http://www.sourceforge.net/projects/KisKis
 */

package de.tbuchloh.kiskis.persistence.exporter;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;

import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.Serializer;
import nu.xom.xslt.XSLTransform;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

import de.tbuchloh.util.xml.XMLException;

/**
 * <b>XMLTransformer</b>:
 * 
 * @author gandalf
 * @version $Id$
 */
public final class XMLTransformer {
    /**
     * Commons Logger for this class
     */
    protected static final Log LOG = LogFactory.getLog(XMLTransformer.class);

    /**
     * creates a new XMLTransformer
     */
    public XMLTransformer() {
        super();
    }

    /**
     * @param stylesheet
     *            is the stylesheet to use.
     * @param is
     *            is the input source.
     * @param os
     *            is the output sink.
     */
    public void transform(final URL stylesheet, final InputStream is, final OutputStream os)
            throws TransformException {
        try {
            LOG.debug("transforming with stylesheet=" + stylesheet);

            final XMLReader reader = XMLReaderFactory.createXMLReader();
            reader.setEntityResolver(new EntityResolver() {
                @Override
                public InputSource resolveEntity(final String publicId, final String systemId)
                        throws SAXException, IOException {
                    if (systemId == null) {
                        throw new IllegalArgumentException("systemId must not be null!");
                    }
                    final int pos = systemId.lastIndexOf(File.separator);
                    String resource = systemId;
                    if (pos >= 0) {
                        resource = resource.substring(pos + 1);
                    }
                    final URL dtd = ClassLoader.getSystemResource(resource);

                    LOG.debug("Resolving " + "systemId=" + systemId + ", resource=" + resource + ", dtd=" + dtd);

                    return new InputSource(dtd.openStream());
                }
            });
            try {
                final Builder builder = new Builder(reader, false);
                final Document s = builder.build(stylesheet.openStream());

                final Document source = builder.build(is);

                final XSLTransform transform = new XSLTransform(s);
                final Document target = XSLTransform.toDocument(transform.transform(source));

                final Serializer ser = new Serializer(os);
                ser.setIndent(2);
                ser.write(target);
            } catch (final Exception e) {
                LOG.error(e, e);
                throw new XMLException(e.getMessage());
            }
        } catch (final Exception e) {
            throw new TransformException(e.getMessage(), e);
        }
    }

}