001/* $Id: XercesParser.java 992082 2010-09-02 19:50:06Z simonetripodi $
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one or more
004 * contributor license agreements.  See the NOTICE file distributed with
005 * this work for additional information regarding copyright ownership.
006 * The ASF licenses this file to You under the Apache License, Version 2.0
007 * (the "License"); you may not use this file except in compliance with
008 * the License.  You may obtain a copy of the License at
009 *
010 *      http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019
020package org.apache.commons.digester.parser;
021
022import java.lang.reflect.Method;
023import java.util.Properties;
024
025import javax.xml.parsers.ParserConfigurationException;
026import javax.xml.parsers.SAXParser;
027import javax.xml.parsers.SAXParserFactory;
028
029import org.apache.commons.logging.Log;
030import org.apache.commons.logging.LogFactory;
031import org.xml.sax.SAXException;
032import org.xml.sax.SAXNotRecognizedException;
033import org.xml.sax.SAXNotSupportedException;
034
035/**
036 * Create a <code>SAXParser</code> based on the underlying Xerces version.
037 * Currently, Xerces 2.3 and up doesn't implement schema validation the same way
038 * 2.1 was. In other to support schema validation in a portable way between 
039 * parser, some features/properties need to be set.
040 *
041 * @since 1.6
042 * @deprecated Create an XMLParser instance yourself, configure validation
043 *             appropriately, and pass it as a parameter to the
044 *             {@link org.apache.commons.digester.Digester} constructor, or use
045 *             {@link org.apache.commons.digester.Digester#setXMLSchema(javax.xml.validation.Schema)} for validation.
046 */
047
048@Deprecated
049public class XercesParser{
050
051    /**
052     * The Log to which all SAX event related logging calls will be made.
053     */
054    protected static Log log =
055        LogFactory.getLog("org.apache.commons.digester.Digester.sax");
056
057
058    /**
059     * The JAXP 1.2 property required to set up the schema location.
060     */
061    private static final String JAXP_SCHEMA_SOURCE =
062        "http://java.sun.com/xml/jaxp/properties/schemaSource";
063
064
065    /**
066     * The JAXP 1.2 property to set up the schemaLanguage used.
067     */
068    protected static String JAXP_SCHEMA_LANGUAGE =
069        "http://java.sun.com/xml/jaxp/properties/schemaLanguage";
070
071
072    /**
073     * Xerces dynamic validation property
074     */
075    protected static String XERCES_DYNAMIC = 
076        "http://apache.org/xml/features/validation/dynamic";
077
078
079    /**
080     * Xerces schema validation property
081     */
082    protected static String XERCES_SCHEMA =
083        "http://apache.org/xml/features/validation/schema";
084
085
086    /**
087     * A <code>float</code> representing the underlying Xerces version
088     */
089    protected static float version;
090
091
092    /**
093     * The current Xerces version.
094     */
095    protected static String versionNumber = null;
096
097
098    /**
099     * Return the current Xerces version.
100     * @return the current Xerces version.
101     */
102    private static String getXercesVersion() {
103        // If for some reason we can't get the version, set it to 1.0.
104        String versionNumber = "1.0";
105        try{
106            // Use reflection to avoid a build dependency with Xerces.
107            Class<?> versionClass = 
108                            Class.forName("org.apache.xerces.impl.Version");
109            // Will return Xerces-J 2.x.0
110            Method method = 
111                versionClass.getMethod("getVersion", (Class[])null); 
112            String version = (String)method.invoke(null, (Object[])null);
113            versionNumber = version.substring( "Xerces-J".length() , 
114                                               version.lastIndexOf(".") ); 
115        } catch (Exception ex){
116            // Do nothing.
117        }
118        return versionNumber;
119    }
120
121
122    /**
123     * Create a <code>SAXParser</code> based on the underlying
124     * <code>Xerces</code> version.
125     * @param properties parser specific properties/features
126     * @return an XML Schema/DTD enabled <code>SAXParser</code>
127     */
128    public static SAXParser newSAXParser(Properties properties) 
129            throws ParserConfigurationException, 
130                   SAXException,
131                   SAXNotSupportedException {
132
133        SAXParserFactory factory =  
134                        (SAXParserFactory)properties.get("SAXParserFactory");
135
136        if (versionNumber == null){
137            versionNumber = getXercesVersion();
138            version = new Float( versionNumber ).floatValue();
139        }
140
141        // Note: 2.2 is completely broken (with XML Schema). 
142        if (version > 2.1) {
143
144            configureXerces(factory);
145            return factory.newSAXParser();
146        } else {
147            SAXParser parser = factory.newSAXParser();
148            configureOldXerces(parser,properties);
149            return parser;
150        }
151    }
152
153
154    /**
155     * Configure schema validation as recommended by the JAXP 1.2 spec.
156     * The <code>properties</code> object may contains information about
157     * the schema local and language. 
158     * @param properties parser optional info
159     */
160    private static void configureOldXerces(SAXParser parser, 
161                                           Properties properties) 
162            throws ParserConfigurationException, 
163                   SAXNotSupportedException {
164
165        String schemaLocation = (String)properties.get("schemaLocation");
166        String schemaLanguage = (String)properties.get("schemaLanguage");
167
168        try{
169            if (schemaLocation != null) {
170                parser.setProperty(JAXP_SCHEMA_LANGUAGE, schemaLanguage);
171                parser.setProperty(JAXP_SCHEMA_SOURCE, schemaLocation);
172            }
173        } catch (SAXNotRecognizedException e){
174            log.info(parser.getClass().getName() + ": " 
175                                        + e.getMessage() + " not supported."); 
176        }
177
178    }
179
180
181    /**
182     * Configure schema validation as recommended by the Xerces spec. 
183     * Both DTD and Schema validation will be enabled simultaneously.
184     * <p>
185     * NOTE: This method is broken. It is supposed to set up validation
186     * against the schema specified in property "schemaLocation", but
187     * it doesn't.
188     *
189     * @param factory SAXParserFactory to be configured
190     */
191    private static void configureXerces(SAXParserFactory factory)
192            throws ParserConfigurationException, 
193                   SAXNotRecognizedException, 
194                   SAXNotSupportedException {
195
196        factory.setFeature(XERCES_DYNAMIC, true);
197        factory.setFeature(XERCES_SCHEMA, true);
198
199    }
200}