com.rexsl.maven.packers.XslPacker Maven / Gradle / Ivy
/**
* Copyright (c) 2011-2013, ReXSL.com
* 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 ReXSL.com 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 HOLDER 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.
*/
package com.rexsl.maven.packers;
import java.io.File;
import java.io.IOException;
import java.io.Reader;
import javax.validation.constraints.NotNull;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
* Packager of XSL files.
*
* All XML comments and unnecessary spaces are removed.
*
*
Since this class is NOT public its documentation is not available online.
* All details of this check should be explained in the JavaDoc of
* {@link PackersProvider}.
*
*
The class is immutable and thread-safe.
*
* @author Dmitry Bashkin ([email protected])
* @author Yegor Bugayenko ([email protected])
* @version $Id$
*/
final class XslPacker extends AbstractPacker {
/**
* Document builder factory.
*/
private static final DocumentBuilderFactory DFACTORY =
DocumentBuilderFactory.newInstance();
/**
* Transformer factory.
*/
private static final TransformerFactory TFACTORY =
TransformerFactory.newInstance();
/**
* Xpath factory.
*/
private static final XPathFactory XPATHFACTORY =
XPathFactory.newInstance();
@Override
protected String extension() {
return "xsl";
}
@Override
protected void pack(@NotNull final Reader input, @NotNull final File dest)
throws IOException {
try {
XslPacker.DFACTORY.setNamespaceAware(true);
final Document document = this.parse(input);
try {
this.clear(document);
} catch (XPathExpressionException ex) {
throw new IllegalStateException(ex);
}
this.transform(dest, document);
} finally {
input.close();
}
}
/**
* Transforms document to provided destination file.
* @param dest Destination file for transformed document.
* @param document Document to transform.
*/
private void transform(final File dest, final Document document) {
try {
final Transformer transformer = XslPacker.TFACTORY.newTransformer();
transformer.setOutputProperty(
OutputKeys.OMIT_XML_DECLARATION,
"yes"
);
transformer.transform(
new DOMSource(document),
new StreamResult(dest)
);
} catch (TransformerConfigurationException ex) {
throw new IllegalStateException(ex);
} catch (TransformerException ex) {
throw new IllegalStateException(ex);
}
}
/**
* Parses reader and returns document.
* @param input Reader to parse.
* @return Resulting document.
* @throws IOException If a problem happens inside
*/
private Document parse(final Reader input) throws IOException {
Document document;
try {
document = XslPacker.DFACTORY
.newDocumentBuilder()
.parse(new InputSource(input));
} catch (ParserConfigurationException ex) {
throw new IllegalStateException(ex);
} catch (SAXException ex) {
throw new IllegalStateException(ex);
}
return document;
}
/**
* Removes comments from the specified Document.
* @param document Document to clear.
* @throws XPathExpressionException If XPATH expression to retrieve comment
* Nodes is wrong.
*/
private void clear(final Document document)
throws XPathExpressionException {
final XPath xpath = XslPacker.XPATHFACTORY.newXPath();
final XPathExpression expr = xpath.compile("//comment()");
final Object result = expr.evaluate(document, XPathConstants.NODESET);
final NodeList nodes = (NodeList) result;
for (int idx = 0; idx < nodes.getLength(); ++idx) {
final Node node = nodes.item(idx);
final Node parent = node.getParentNode();
if (null == parent) {
throw new IllegalStateException(
"Root element cannot be a comment"
);
}
parent.removeChild(node);
}
}
}