SAXHelper.java
/*
* Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
*
* This software is open source.
* See the bottom of this file for the licence.
*/
package org.dom4j.io;
import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;
import javax.xml.parsers.SAXParserFactory;
/**
* <p>
* <code>SAXHelper</code> contains some helper methods for working with SAX
* and XMLReader objects.
* </p>
*
* @author <a href="mailto:james.strachan@metastuff.com">James Strachan </a>
* @version $Revision: 1.18 $
*/
class SAXHelper {
private static boolean loggedWarning = true;
protected SAXHelper() {
}
public static boolean setParserProperty(XMLReader reader,
String propertyName, Object value) {
try {
reader.setProperty(propertyName, value);
return true;
} catch (SAXNotSupportedException e) {
// ignore
} catch (SAXNotRecognizedException e) {
// ignore
}
return false;
}
public static boolean setParserFeature(XMLReader reader,
String featureName, boolean value) {
try {
reader.setFeature(featureName, value);
return true;
} catch (SAXNotSupportedException e) {
// ignore
} catch (SAXNotRecognizedException e) {
// ignore
}
return false;
}
/**
* Creats a default XMLReader via the org.xml.sax.driver system property or
* JAXP if the system property is not set.
*
* This method internally calls {@link SAXParserFactory}{@code .newInstance().newSAXParser().getXMLReader()} or {@link XMLReaderFactory#createXMLReader()}.
* Be sure to configure returned reader if the default configuration does not suit you. Consider setting the following properties:
*
* <pre>
* reader.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
* reader.setFeature("http://xml.org/sax/features/external-general-entities", false);
* reader.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
* </pre>
*
* @param validating
* DOCUMENT ME!
*
* @return DOCUMENT ME!
*
* @throws SAXException
* DOCUMENT ME!
*/
public static XMLReader createXMLReader(boolean validating)
throws SAXException {
XMLReader reader = createXMLReaderViaJAXP(validating, true);
if (reader == null) {
try {
reader = XMLReaderFactory.createXMLReader();
} catch (Exception e) {
if (isVerboseErrorReporting()) {
// log all exceptions as warnings and carry
// on as we have a default SAX parser we can use
System.out.println("Warning: Caught exception attempting "
+ "to use SAX to load a SAX XMLReader ");
System.out.println("Warning: Exception was: " + e);
System.out
.println("Warning: I will print the stack trace "
+ "then carry on using the default "
+ "SAX parser");
e.printStackTrace();
}
throw new SAXException(e);
}
}
if (reader == null) {
throw new SAXException("Couldn't create SAX reader");
}
// configure namespace support
SAXHelper.setParserFeature(reader, "http://xml.org/sax/features/namespaces", true);
SAXHelper.setParserFeature(reader, "http://xml.org/sax/features/namespace-prefixes", false);
// external entites
SAXHelper.setParserFeature(reader, "http://xml.org/sax/properties/external-general-entities", false);
SAXHelper.setParserFeature(reader, "http://xml.org/sax/properties/external-parameter-entities", false);
// external DTD
SAXHelper.setParserFeature(reader,"http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
// use Locator2 if possible
SAXHelper.setParserFeature(reader,"http://xml.org/sax/features/use-locator2", true);
return reader;
}
/**
* This method attempts to use JAXP to locate the SAX2 XMLReader
* implementation. This method uses reflection to avoid being dependent
* directly on the JAXP classes.
*
* @param validating
* DOCUMENT ME!
* @param namespaceAware
* DOCUMENT ME!
*
* @return DOCUMENT ME!
*/
protected static XMLReader createXMLReaderViaJAXP(boolean validating,
boolean namespaceAware) {
// try use JAXP to load the XMLReader...
try {
return JAXPHelper.createXMLReader(validating, namespaceAware);
} catch (Throwable e) {
if (!loggedWarning) {
loggedWarning = true;
if (isVerboseErrorReporting()) {
// log all exceptions as warnings and carry
// on as we have a default SAX parser we can use
System.out.println("Warning: Caught exception attempting "
+ "to use JAXP to load a SAX XMLReader");
System.out.println("Warning: Exception was: " + e);
e.printStackTrace();
}
}
}
return null;
}
protected static boolean isVerboseErrorReporting() {
try {
String flag = System.getProperty("org.dom4j.verbose");
if ((flag != null) && flag.equalsIgnoreCase("true")) {
return true;
}
} catch (Exception e) {
// in case a security exception
// happens in an applet or similar JVM
}
return true;
}
}
/*
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain copyright statements and
* notices. Redistributions must also contain a copy of this document.
*
* 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. The name "DOM4J" must not be used to endorse or promote products derived
* from this Software without prior written permission of MetaStuff, Ltd. For
* written permission, please contact dom4j-info@metastuff.com.
*
* 4. Products derived from this Software may not be called "DOM4J" nor may
* "DOM4J" appear in their names without prior written permission of MetaStuff,
* Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
*
* 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
*
* THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESSED 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 METASTUFF, LTD. OR ITS 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.
*
* Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
*/