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 info@exolab.org.
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 2001,2003 (C) Exoffice Technologies Inc. All Rights Reserved.
42 *
43 * $Id: AttributeExpander.java,v 1.1 2004/11/26 01:50:41 tanderson Exp $
44 */
45 package org.exolab.jms.config;
46
47 import java.io.IOException;
48 import java.io.Reader;
49
50 import org.apache.commons.logging.Log;
51 import org.apache.commons.logging.LogFactory;
52
53 import org.exolab.castor.util.Configuration;
54 import org.exolab.castor.xml.EventProducer;
55 import org.xml.sax.AttributeList;
56 import org.xml.sax.DocumentHandler;
57 import org.xml.sax.ErrorHandler;
58 import org.xml.sax.InputSource;
59 import org.xml.sax.Locator;
60 import org.xml.sax.Parser;
61 import org.xml.sax.SAXException;
62 import org.xml.sax.helpers.AttributeListImpl;
63
64
65 /***
66 * This class expands attributes in XML documents as the document is being
67 * parsed. It is designed to be used in conjunction with the Castor
68 * unmarshalling framework.
69 * <p>
70 * To be expanded, attribute values must contain text of the form
71 * <i>${property.name}</i>, where <i>property.name</i> is a property returned
72 * by <code>System.getProperty()</code>.<br>
73 * If no property exists, the attribute value remains unchanged.
74 *
75 * @version $Revision: 1.1 $ $Date: 2004/11/26 01:50:41 $
76 * @author <a href="mailto:tima@intalio.com">Tim Anderson</a>
77 * @see EventProducer
78 * @see org.exolab.castor.xml.Unmarshaller
79 */
80 public class AttributeExpander implements EventProducer {
81
82 private DocumentHandler _handler = null;
83 private Reader _reader = null;
84
85 /***
86 * The logger
87 */
88 private static final Log _log =
89 LogFactory.getLog(AttributeExpander.class);
90
91
92 /***
93 * Construct a new instance
94 *
95 * @param reader the XML file reader
96 */
97 public AttributeExpander(Reader reader) {
98 _reader = reader;
99 }
100
101 /***
102 * Sets the DocumentHandler to send SAX events to
103 */
104 public void setDocumentHandler(DocumentHandler handler) {
105 _handler = handler;
106 }
107
108 /***
109 * Signals to start producing events.
110 */
111 public void start() throws SAXException {
112 Parser parser = Configuration.getDefaultParser();
113 if (parser == null) {
114 throw new SAXException("Unable to create parser");
115 }
116
117 DocumentHandler handler = new AttributeInterceptor();
118 parser.setDocumentHandler(handler);
119 try {
120 parser.parse(new InputSource(_reader));
121 } catch (IOException exception) {
122 throw new SAXException(exception.getMessage(), exception);
123 }
124 }
125
126 /***
127 * Helper class to intercept {@link #startElement} calls, expanding
128 * any attributes.
129 */
130 private class AttributeInterceptor implements DocumentHandler {
131
132 public void setDocumentLocator(Locator locator) {
133 _handler.setDocumentLocator(locator);
134 }
135
136 public void startDocument() throws SAXException {
137 _handler.startDocument();
138 }
139
140 public void endDocument() throws SAXException {
141 _handler.endDocument();
142 }
143
144 public void startElement(String name, AttributeList list)
145 throws SAXException {
146
147 AttributeListImpl replaced = new AttributeListImpl();
148 for (int i = 0; i < list.getLength(); i++) {
149 String value = expand(list.getName(i), list.getValue(i));
150 replaced.addAttribute(list.getName(i), list.getType(i), value);
151 }
152 _handler.startElement(name, replaced);
153 }
154
155 public void endElement(String name) throws SAXException {
156 _handler.endElement(name);
157 }
158
159 public void characters(char[] ch, int start, int length)
160 throws SAXException {
161 _handler.characters(ch, start, length);
162 }
163
164 public void ignorableWhitespace(char[] ch, int start, int length)
165 throws SAXException {
166 _handler.ignorableWhitespace(ch, start, length);
167 }
168
169 public void processingInstruction(String target, String data)
170 throws SAXException {
171 _handler.processingInstruction(target, data);
172 }
173
174 private String expand(String attribute, String value) {
175 StringBuffer buffer = new StringBuffer();
176 int prev = 0;
177 int pos;
178 while ((pos = value.indexOf("${", prev)) >= 0) {
179 if (pos > 0) {
180 buffer.append(value.substring(prev, pos));
181 }
182 int index = value.indexOf('}', pos);
183 if (index < 0) {
184
185 _log.warn("Cannot expand " + attribute
186 + " - invalid format: " + value);
187 buffer.append("${");
188 prev = pos + 2;
189 } else {
190 String name = value.substring(pos + 2, index);
191 String property = System.getProperty(name);
192 if (property != null) {
193 buffer.append(property);
194 } else {
195
196
197 _log.warn("Cannot expand " + attribute
198 + " as property " + name
199 + " is not defined");
200 buffer.append("${");
201 buffer.append(name);
202 buffer.append("}");
203 }
204 prev = index + 1;
205 }
206 }
207 if (prev < value.length()) {
208 buffer.append(value.substring(prev));
209 }
210 String result = buffer.toString();
211 return result;
212 }
213
214 }
215
216 }