Commons Digester example source code file (XercesParser.java)

This example Commons Digester source code file (XercesParser.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Digester tags/keywords

class, jaxp_schema_source, parser, parserconfigurationexception, parserconfigurationexception, properties, reflection, sax, saxnotrecognizedexception, saxnotrecognizedexception, saxnotsupportedexception, saxnotsupportedexception, saxparser, saxparserfactory, string, string, util, xercesparser, xml

The Commons Digester XercesParser.java source code

/* $Id: XercesParser.java 992082 2010-09-02 19:50:06Z simonetripodi $
 *
 * 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.commons.digester.parser;

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.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;

/**
 * Create a <code>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
 * @deprecated Create an XMLParser instance yourself, configure validation
 *             appropriately, and pass it as a parameter to the
 *             {@link org.apache.commons.digester.Digester} constructor, or use
 *             {@link org.apache.commons.digester.Digester#setXMLSchema(javax.xml.validation.Schema)} for validation.
 */

@Deprecated
public class XercesParser{

    /**
     * The Log to which all SAX event related logging calls will be made.
     */
    protected static Log log =
        LogFactory.getLog("org.apache.commons.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 <code>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 <code>SAXParser based on the underlying
     * <code>Xerces version.
     * @param properties parser specific properties/features
     * @return an XML Schema/DTD enabled <code>SAXParser
     */
    public static SAXParser newSAXParser(Properties properties) 
            throws ParserConfigurationException, 
                   SAXException,
                   SAXNotSupportedException {

        SAXParserFactory factory =  
                        (SAXParserFactory)properties.get("SAXParserFactory");

        if (versionNumber == null){
            versionNumber = getXercesVersion();
            version = new Float( versionNumber ).floatValue();
        }

        // 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 <code>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.
     * <p>
     * NOTE: This method is broken. It is supposed to set up validation
     * against the schema specified in property "schemaLocation", but
     * it doesn't.
     *
     * @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);

    }
}