org.apache.tomcat.util.digester.XercesParser Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.tomcat.util.digester;
import java.lang.reflect.Method;
import java.util.Properties;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
/**
* Create a SAXParser based on the underlying Xerces version.
* Currently, Xerces 2.3 and up doesn't implement schema validation the same way
* 2.1 was. In other to support schema validation in a portable way between
* parser, some features/properties need to be set.
*
* @since 1.6
*/
public class XercesParser{
/**
* The Log to which all SAX event related logging calls will be made.
*/
private static final Log log =
LogFactory.getLog("org.apache.tomcat.util.digester.Digester.sax");
/**
* The JAXP 1.2 property required to set up the schema location.
*/
private static final String JAXP_SCHEMA_SOURCE =
"http://java.sun.com/xml/jaxp/properties/schemaSource";
/**
* The JAXP 1.2 property to set up the schemaLanguage used.
*/
protected static String JAXP_SCHEMA_LANGUAGE =
"http://java.sun.com/xml/jaxp/properties/schemaLanguage";
/**
* Xerces dynamic validation property
*/
protected static String XERCES_DYNAMIC =
"http://apache.org/xml/features/validation/dynamic";
/**
* Xerces schema validation property
*/
protected static String XERCES_SCHEMA =
"http://apache.org/xml/features/validation/schema";
/**
* A float representing the underlying Xerces version
*/
protected static float version;
/**
* The current Xerces version.
*/
protected static String versionNumber = null;
/**
* Return the current Xerces version.
* @return the current Xerces version.
*/
private static String getXercesVersion() {
// If for some reason we can't get the version, set it to 1.0.
String versionNumber = "1.0";
try{
// Use reflection to avoid a build dependency with Xerces.
Class versionClass =
Class.forName("org.apache.xerces.impl.Version");
// Will return Xerces-J 2.x.0
Method method =
versionClass.getMethod("getVersion", (Class[]) null);
String version = (String)method.invoke(null, (Object[]) null);
versionNumber = version.substring( "Xerces-J".length() ,
version.lastIndexOf('.') );
} catch (Exception ex){
// Do nothing.
}
return versionNumber;
}
/**
* Create a SAXParser based on the underlying
* Xerces version.
* @param properties parser specific properties/features
* @return an XML Schema/DTD enabled SAXParser
*/
public static SAXParser newSAXParser(Properties properties)
throws ParserConfigurationException,
SAXException,
SAXNotSupportedException {
SAXParserFactory factory =
(SAXParserFactory)properties.get("SAXParserFactory");
if (versionNumber == null){
versionNumber = getXercesVersion();
version = Float.parseFloat(versionNumber);
}
// Note: 2.2 is completely broken (with XML Schema).
if (version > 2.1) {
configureXerces(factory);
return factory.newSAXParser();
} else {
SAXParser parser = factory.newSAXParser();
configureOldXerces(parser,properties);
return parser;
}
}
/**
* Configure schema validation as recommended by the JAXP 1.2 spec.
* The properties object may contains information about
* the schema local and language.
* @param properties parser optional info
*/
private static void configureOldXerces(SAXParser parser,
Properties properties)
throws ParserConfigurationException,
SAXNotSupportedException {
String schemaLocation = (String)properties.get("schemaLocation");
String schemaLanguage = (String)properties.get("schemaLanguage");
try{
if (schemaLocation != null) {
parser.setProperty(JAXP_SCHEMA_LANGUAGE, schemaLanguage);
parser.setProperty(JAXP_SCHEMA_SOURCE, schemaLocation);
}
} catch (SAXNotRecognizedException e){
log.info(parser.getClass().getName() + ": "
+ e.getMessage() + " not supported.");
}
}
/**
* Configure schema validation as recommended by the Xerces spec.
* Both DTD and Schema validation will be enabled simultaneously.
* @param factory SAXParserFactory to be configured
*/
private static void configureXerces(SAXParserFactory factory)
throws ParserConfigurationException,
SAXNotRecognizedException,
SAXNotSupportedException {
factory.setFeature(XERCES_DYNAMIC, true);
factory.setFeature(XERCES_SCHEMA, true);
}
}