/**
* EasyBeans
* Copyright (C) 2006-2007 Bull S.A.S.
* Contact: easybeans@ow2.org
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
* --------------------------------------------------------------------------
* $Id: DocumentParser.java 5369 2010-02-24 14:58:19Z benoitf $
* --------------------------------------------------------------------------
*/
package org.ow2.easybeans.util.xml;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.net.URLConnection;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
* Allows to parse an xml file.
* @author Florent Benoit
*/
public final class DocumentParser {
/**
* Utility class.
*/
private DocumentParser() {
}
/**
* Builds a new Document for a given xml file.
* @param url the URL of the the XML file.
* @param isValidating validate or not the xml file ?
* @param entityResolver the entityResolver used to validate document (if
* validating = true)
* @throws DocumentParserException if creating of builder fails or parsing
* fails.
* @return an application object.
*/
public static Document getDocument(final URL url, final boolean isValidating, final EntityResolver entityResolver)
throws DocumentParserException {
// build factory
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
// XML files use schemas.
factory.setNamespaceAware(true);
factory.setValidating(isValidating);
// ignore white space can only be set if parser is validating
if (isValidating) {
factory.setIgnoringElementContentWhitespace(true);
factory.setAttribute("http://apache.org/xml/features/validation/schema", Boolean.valueOf(isValidating));
factory.setAttribute("http://apache.org/xml/features/validation/schema-full-checking", Boolean.valueOf(true));
}
// Add schema location
if (isValidating) {
// Needs to get the version attribute and then set the schema
// location. For this, get the version by parsing the document
// without validation
Document detectDocument = getDocument(url, false, entityResolver);
// Root element = <persistence>
Element persistenceRootElement = detectDocument.getDocumentElement();
String version = XMLUtils.getAttributeValue(persistenceRootElement, "version");
if ("1.0".equals(version)) {
factory.setAttribute("http://apache.org/xml/properties/schema/external-schemaLocation",
"http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd");
} else if ("2.0".equals(version)) {
factory.setAttribute("http://apache.org/xml/properties/schema/external-schemaLocation",
"http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd");
} else {
// This is a required attribute, needs to be set by the user !
throw new DocumentParserException("Cannot detect the version of the Persistence schema from the URL '" + url
+ "'");
}
}
// Build a document builder
DocumentBuilder builder = null;
try {
builder = factory.newDocumentBuilder();
} catch (ParserConfigurationException e) {
throw new DocumentParserException("Cannot build a document builder", e);
}
// Error handler (throwing exceptions)
builder.setErrorHandler(new EasyBeansErrorHandler());
// Dummy entity resolver if there is none
if (entityResolver == null) {
builder.setEntityResolver(new EmptyEntityResolver());
} else {
builder.setEntityResolver(entityResolver);
}
// Parse document
URLConnection urlConnection = null;
try {
urlConnection = url.openConnection();
} catch (IOException e) {
throw new DocumentParserException("Cannot open a connection on URL '" + url + "'", e);
}
urlConnection.setDefaultUseCaches(false);
Reader reader = null;
try {
reader = new InputStreamReader(urlConnection.getInputStream());
} catch (IOException e) {
throw new DocumentParserException("Cannot build an input stream reader on URL '" + url + "'", e);
}
InputSource inputSource = new InputSource(reader);
Document document = null;
try {
document = builder.parse(inputSource);
} catch (SAXException e) {
throw new DocumentParserException("Cannot parse the XML file '" + url + "'.", e);
} catch (IOException e) {
throw new DocumentParserException("Cannot parse the XML file '" + url + "'.", e);
} finally {
// close InputStream when parsing is finished
try {
reader.close();
} catch (IOException e) {
throw new DocumentParserException("Cannot close the inputsource of the XML file'" + url + "'.", e);
}
}
return document;
}
}