1 /***
2 * Redistribution and use of this software and associated documentation
3 * ("Software"), with or without modification, are permitted provided
4 * that the following conditions are met:
5 *
6 * 1. Redistributions of source code must retain copyright
7 * statements and notices. Redistributions must also contain a
8 * copy of this document.
9 *
10 * 2. Redistributions in binary form must reproduce the
11 * above copyright notice, this list of conditions and the
12 * following disclaimer in the documentation and/or other
13 * materials provided with the distribution.
14 *
15 * 3. The name "Exolab" must not be used to endorse or promote
16 * products derived from this Software without prior written
17 * permission of Exoffice Technologies. For written permission,
18 * please contact tma@netspace.net.au.
19 *
20 * 4. Products derived from this Software may not be called "Exolab"
21 * nor may "Exolab" appear in their names without prior written
22 * permission of Exoffice Technologies. Exolab is a registered
23 * trademark of Exoffice Technologies.
24 *
25 * 5. Due credit should be given to the Exolab Project
26 * (http://www.exolab.org/).
27 *
28 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39 * OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Copyright 2003-2004 (C) Exoffice Technologies Inc. All Rights Reserved.
42 *
43 * $Id: ConfigExpander.java,v 1.2 2004/02/03 21:52:13 tanderson Exp $
44 */
45 package org.exolab.jmscts.util;
46
47 import java.io.IOException;
48 import java.io.Reader;
49
50 import org.xml.sax.AttributeList;
51 import org.xml.sax.DocumentHandler;
52 import org.xml.sax.Locator;
53 import org.xml.sax.InputSource;
54 import org.xml.sax.Parser;
55 import org.xml.sax.SAXException;
56 import org.xml.sax.helpers.AttributeListImpl;
57
58 import org.apache.log4j.Category;
59
60 import org.exolab.castor.util.Configuration;
61 import org.exolab.castor.xml.EventProducer;
62
63
64 /***
65 * This class expands elements and attributes in XML documents as the document
66 * is being parsed. It is designed to be used in conjunction with the Castor
67 * unmarshalling framework.
68 * <p>
69 * To be expanded, values must contain text of the form <i>${property.name}</i>
70 * , where <i>property.name</i> is a property returned
71 * by System.getProperty().<br>
72 * If no property exists, the value remains unchanged.
73 *
74 * @version $Revision: 1.2 $ $Date: 2004/02/03 21:52:13 $
75 * @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
76 * @see EventProducer
77 * @see org.exolab.castor.xml.Unmarshaller
78 */
79 public class ConfigExpander implements EventProducer {
80
81 /***
82 * The document handler
83 */
84 private DocumentHandler _handler = null;
85
86 /***
87 * The XML document reader
88 */
89 private Reader _reader = null;
90
91 /***
92 * The current element name
93 */
94 private String _name = null;
95
96 /***
97 * The logger
98 */
99 private static final Category log =
100 Category.getInstance(ConfigExpander.class);
101
102
103 /***
104 * Construct a new instance
105 *
106 * @param reader the XML document reader
107 */
108 public ConfigExpander(Reader reader) {
109 _reader = reader;
110 }
111
112 /***
113 * Sets the DocumentHandler to send SAX events to
114 *
115 * @param handler the handler to forward events to
116 */
117 public void setDocumentHandler(DocumentHandler handler) {
118 _handler = handler;
119 }
120
121 /***
122 * Signals to start producing events
123 *
124 * @throws SAXException if the document cannot be parsed
125 */
126 public void start() throws SAXException {
127 Parser parser = Configuration.getDefaultParser();
128 if (parser == null) {
129 throw new SAXException("Unable to create parser");
130 }
131
132 DocumentHandler handler = new Expander();
133 parser.setDocumentHandler(handler);
134 try {
135 parser.parse(new InputSource(_reader));
136 } catch (IOException exception) {
137 throw new SAXException(exception.getMessage(), exception);
138 }
139 }
140
141 /***
142 * Helper class to intercept {@link #startElement} calls, expanding
143 * any attributes.
144 */
145 private class Expander implements DocumentHandler {
146
147 /***
148 * Receive an object for locating the origin of SAX document events.
149 *
150 * @param locator an object that can return the location of any SAX
151 * document event
152 */
153 public void setDocumentLocator(Locator locator) {
154 _handler.setDocumentLocator(locator);
155 }
156
157 /***
158 * Receive notification of the beginning of a document.
159 *
160 * @throws SAXException any SAX exception, possibly wrapping another
161 * exception.
162 */
163 public void startDocument() throws SAXException {
164 _handler.startDocument();
165 }
166
167 /***
168 * Receive notification of the end of a document.
169 * @throws SAXException any SAX exception, possibly wrapping another
170 * exception.
171 */
172 public void endDocument() throws SAXException {
173 _handler.endDocument();
174 }
175
176 /***
177 * Receive notification of the beginning of an element.
178 *
179 * @param name the element name
180 * @param list the attributes attached to the element, if any
181 * @throws SAXException any SAX exception, possibly wrapping another
182 * exception.
183 */
184 public void startElement(String name, AttributeList list)
185 throws SAXException {
186
187 AttributeListImpl replaced = new AttributeListImpl();
188 for (int i = 0; i < list.getLength(); i++) {
189 String value = expand(list.getName(i), list.getValue(i));
190 replaced.addAttribute(list.getName(i), list.getType(i), value);
191 }
192 _name = name;
193 _handler.startElement(name, replaced);
194 }
195
196 /***
197 * Receive notification of the end of an element
198 *
199 * @param name the element name
200 * @throws SAXException any SAX exception, possibly wrapping another
201 * exception.
202 */
203 public void endElement(String name) throws SAXException {
204 _handler.endElement(name);
205 _name = null;
206 }
207
208 /***
209 * Receive notification of character data
210 *
211 * @param ch the characters from the XML document
212 * @param start the start position in the array
213 * @param length the number of characters to read from the array
214 * @throws SAXException any SAX exception, possibly wrapping another
215 * exception.
216 */
217 public void characters(char[] ch, int start, int length)
218 throws SAXException {
219
220 String content = new String(ch, start, length);
221 content = expand(_name, content);
222 _handler.characters(content.toCharArray(), 0, content.length());
223 }
224
225 /***
226 * Receive notification of ignorable whitespace in element content.
227 *
228 * @param ch the characters from the XML document
229 * @param start the start position in the array
230 * @param length the number of characters to read from the array
231 * @throws SAXException any SAX exception, possibly wrapping another
232 * exception.
233 */
234 public void ignorableWhitespace(char[] ch, int start, int length)
235 throws SAXException {
236 _handler.ignorableWhitespace(ch, start, length);
237 }
238
239 /***
240 * Receive notification of a processing instruction.
241 *
242 * @param target the processing instruction target
243 * @param data the processing instruction data, or null if none was
244 * supplied
245 * @throws SAXException any SAX exception, possibly wrapping another
246 * exception.
247 */
248 public void processingInstruction(String target, String data)
249 throws SAXException {
250 _handler.processingInstruction(target, data);
251 }
252
253 /***
254 * Expand a value, if its contains embedded ${<property>} text
255 *
256 * @param name the attribute or element name
257 * @param value the content to expand
258 * @return the expanded value if it contained embedded text,
259 * and the property refers to a value system property. If not, returns
260 * value unchanged.
261 */
262 private String expand(String name, String value) {
263 StringBuffer buffer = new StringBuffer();
264 int prev = 0;
265 int pos;
266 while ((pos = value.indexOf("${", prev)) >= 0) {
267 if (pos > 0) {
268 buffer.append(value.substring(prev, pos));
269 }
270 int index = value.indexOf('}', pos);
271 if (index < 0) {
272 // invalid format
273 log.debug(
274 "Cannot expand as format is invalid: "
275 + "name=" + name + ", value=" + value);
276 buffer.append("${");
277 prev = pos + 2;
278 } else {
279 String propertyName = value.substring(pos + 2, index);
280 String propertyValue = System.getProperty(propertyName);
281 if (propertyValue != null) {
282 buffer.append(propertyValue);
283 } else {
284 log.debug("Cannot expand " + name + " as property="
285 + propertyName + " is not defined");
286 buffer.append("${");
287 buffer.append(propertyName);
288 buffer.append("}");
289 }
290 prev = index + 1;
291 }
292 }
293 if (prev < value.length()) {
294 buffer.append(value.substring(prev));
295 }
296 String result = buffer.toString();
297 return result;
298 }
299
300 }
301
302 }
This page was automatically generated by Maven