1 /* $Id: XercesParser.java 471661 2006-11-06 08:09:25Z skitching $
2 *
3 * Licensed to the Apache Software Foundation (ASF) under one or more
4 * contributor license agreements. See the NOTICE file distributed with
5 * this work for additional information regarding copyright ownership.
6 * The ASF licenses this file to You under the Apache License, Version 2.0
7 * (the "License"); you may not use this file except in compliance with
8 * the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19
20 package org.apache.commons.digester.parser;
21
22 import java.lang.reflect.Method;
23 import java.util.Properties;
24
25 import javax.xml.parsers.ParserConfigurationException;
26 import javax.xml.parsers.SAXParser;
27 import javax.xml.parsers.SAXParserFactory;
28
29 import org.apache.commons.logging.Log;
30 import org.apache.commons.logging.LogFactory;
31 import org.xml.sax.SAXException;
32 import org.xml.sax.SAXNotRecognizedException;
33 import org.xml.sax.SAXNotSupportedException;
34
35 /**
36 * Create a <code>SAXParser</code> based on the underlying Xerces version.
37 * Currently, Xerces 2.3 and up doesn't implement schema validation the same way
38 * 2.1 was. In other to support schema validation in a portable way between
39 * parser, some features/properties need to be set.
40 *
41 * @since 1.6
42 */
43
44 public class XercesParser{
45
46 /**
47 * The Log to which all SAX event related logging calls will be made.
48 */
49 protected static Log log =
50 LogFactory.getLog("org.apache.commons.digester.Digester.sax");
51
52
53 /**
54 * The JAXP 1.2 property required to set up the schema location.
55 */
56 private static final String JAXP_SCHEMA_SOURCE =
57 "http://java.sun.com/xml/jaxp/properties/schemaSource";
58
59
60 /**
61 * The JAXP 1.2 property to set up the schemaLanguage used.
62 */
63 protected static String JAXP_SCHEMA_LANGUAGE =
64 "http://java.sun.com/xml/jaxp/properties/schemaLanguage";
65
66
67 /**
68 * Xerces dynamic validation property
69 */
70 protected static String XERCES_DYNAMIC =
71 "http://apache.org/xml/features/validation/dynamic";
72
73
74 /**
75 * Xerces schema validation property
76 */
77 protected static String XERCES_SCHEMA =
78 "http://apache.org/xml/features/validation/schema";
79
80
81 /**
82 * A <code>float</code> representing the underlying Xerces version
83 */
84 protected static float version;
85
86
87 /**
88 * The current Xerces version.
89 */
90 protected static String versionNumber = null;
91
92
93 /**
94 * Return the current Xerces version.
95 * @return the current Xerces version.
96 */
97 private static String getXercesVersion() {
98 // If for some reason we can't get the version, set it to 1.0.
99 String versionNumber = "1.0";
100 try{
101 // Use reflection to avoid a build dependency with Xerces.
102 Class versionClass =
103 Class.forName("org.apache.xerces.impl.Version");
104 // Will return Xerces-J 2.x.0
105 Method method =
106 versionClass.getMethod("getVersion", (Class[])null);
107 String version = (String)method.invoke(null, (Object[])null);
108 versionNumber = version.substring( "Xerces-J".length() ,
109 version.lastIndexOf(".") );
110 } catch (Exception ex){
111 // Do nothing.
112 }
113 return versionNumber;
114 }
115
116
117 /**
118 * Create a <code>SAXParser</code> based on the underlying
119 * <code>Xerces</code> version.
120 * @param properties parser specific properties/features
121 * @return an XML Schema/DTD enabled <code>SAXParser</code>
122 */
123 public static SAXParser newSAXParser(Properties properties)
124 throws ParserConfigurationException,
125 SAXException,
126 SAXNotSupportedException {
127
128 SAXParserFactory factory =
129 (SAXParserFactory)properties.get("SAXParserFactory");
130
131 if (versionNumber == null){
132 versionNumber = getXercesVersion();
133 version = new Float( versionNumber ).floatValue();
134 }
135
136 // Note: 2.2 is completely broken (with XML Schema).
137 if (version > 2.1) {
138
139 configureXerces(factory);
140 return factory.newSAXParser();
141 } else {
142 SAXParser parser = factory.newSAXParser();
143 configureOldXerces(parser,properties);
144 return parser;
145 }
146 }
147
148
149 /**
150 * Configure schema validation as recommended by the JAXP 1.2 spec.
151 * The <code>properties</code> object may contains information about
152 * the schema local and language.
153 * @param properties parser optional info
154 */
155 private static void configureOldXerces(SAXParser parser,
156 Properties properties)
157 throws ParserConfigurationException,
158 SAXNotSupportedException {
159
160 String schemaLocation = (String)properties.get("schemaLocation");
161 String schemaLanguage = (String)properties.get("schemaLanguage");
162
163 try{
164 if (schemaLocation != null) {
165 parser.setProperty(JAXP_SCHEMA_LANGUAGE, schemaLanguage);
166 parser.setProperty(JAXP_SCHEMA_SOURCE, schemaLocation);
167 }
168 } catch (SAXNotRecognizedException e){
169 log.info(parser.getClass().getName() + ": "
170 + e.getMessage() + " not supported.");
171 }
172
173 }
174
175
176 /**
177 * Configure schema validation as recommended by the Xerces spec.
178 * Both DTD and Schema validation will be enabled simultaneously.
179 * <p>
180 * NOTE: This method is broken. It is supposed to set up validation
181 * against the schema specified in property "schemaLocation", but
182 * it doesn't.
183 *
184 * @param factory SAXParserFactory to be configured
185 */
186 private static void configureXerces(SAXParserFactory factory)
187 throws ParserConfigurationException,
188 SAXNotRecognizedException,
189 SAXNotSupportedException {
190
191 factory.setFeature(XERCES_DYNAMIC, true);
192 factory.setFeature(XERCES_SCHEMA, true);
193
194 }
195 }
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