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Java > Open Source Codes > org > apache > commons > configuration > XMLPropertiesConfiguration


1 /*
2  * Copyright 2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License")
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.apache.commons.configuration;
18
19 import java.io.File JavaDoc;
20 import java.io.PrintWriter JavaDoc;
21 import java.io.Reader JavaDoc;
22 import java.io.Writer JavaDoc;
23 import java.net.URL JavaDoc;
24 import java.util.Iterator JavaDoc;
25 import java.util.List JavaDoc;
26
27 import org.apache.commons.digester.Digester;
28 import org.apache.commons.lang.StringEscapeUtils;
29 import org.apache.commons.lang.StringUtils;
30 import org.xml.sax.EntityResolver JavaDoc;
31 import org.xml.sax.InputSource JavaDoc;
32
33 /**
34  * This configuration implements the XML properties format introduced in Java
35  * 5.0, see http://java.sun.com/j2se/1.5.0/docs/api/java/util/Properties.html.
36  * An XML properties file looks like this:
37  *
38  * <pre>
39  * &lt;?xml version="1.0"?>
40  * &lt;!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
41  * &lt;properties>
42  * &lt;comment>Description of the property list&lt;/comment>
43  * &lt;entry key="key1">value1&lt;/entry>
44  * &lt;entry key="key2">value2&lt;/entry>
45  * &lt;entry key="key3">value3&lt;/entry>
46  * &lt;/properties>
47  * &lt;/pre>
48  *
49  * The Java 5.0 runtime is not required to use this class. The default encoding
50  * for this configuration format is UTF-8. Note that unlike
51  * <code>PropertiesConfiguration</code>, <code>XMLPropertiesConfiguration</code>
52  * does not support includes.
53  *
54  * @since 1.1
55  *
56  * @author Emmanuel Bourg
57  * @version $Revision: 155408 $, $Date: 2005-02-26 13:56:39 +0100 (Sa, 26 Feb 2005) $
58  */
59 public class XMLPropertiesConfiguration extends PropertiesConfiguration
60 {
61     /**
62      * The default encoding (UTF-8 as specified by http://java.sun.com/j2se/1.5.0/docs/api/java/util/Properties.html)
63      */
64     private static final String JavaDoc DEFAULT_ENCODING = "UTF-8";
65
66     // initialization block to set the encoding before loading the file in the constructors
67 {
68         setEncoding(DEFAULT_ENCODING);
69     }
70
71     /**
72      * Creates an empty XMLPropertyConfiguration object which can be
73      * used to synthesize a new Properties file by adding values and
74      * then saving(). An object constructed by this C'tor can not be
75      * tickled into loading included files because it cannot supply a
76      * base for relative includes.
77      */
78     public XMLPropertiesConfiguration()
79     {
80         super();
81     }
82
83     /**
84      * Creates and loads the xml properties from the specified file.
85      * The specified file can contain "include" properties which then
86      * are loaded and merged into the properties.
87      *
88      * @param fileName The name of the properties file to load.
89      * @throws ConfigurationException Error while loading the properties file
90      */
91     public XMLPropertiesConfiguration(String JavaDoc fileName) throws ConfigurationException
92     {
93         super(fileName);
94     }
95
96     /**
97      * Creates and loads the xml properties from the specified file.
98      * The specified file can contain "include" properties which then
99      * are loaded and merged into the properties.
100      *
101      * @param file The properties file to load.
102      * @throws ConfigurationException Error while loading the properties file
103      */
104     public XMLPropertiesConfiguration(File JavaDoc file) throws ConfigurationException
105     {
106         super(file);
107     }
108
109     /**
110      * Creates and loads the xml properties from the specified URL.
111      * The specified file can contain "include" properties which then
112      * are loaded and merged into the properties.
113      *
114      * @param url The location of the properties file to load.
115      * @throws ConfigurationException Error while loading the properties file
116      */
117     public XMLPropertiesConfiguration(URL JavaDoc url) throws ConfigurationException
118     {
119         super(url);
120     }
121
122     public void load(Reader JavaDoc in) throws ConfigurationException
123     {
124         // todo: replace with a pure SAX implementation to reduce the dependencies
125
126         // set up the digester
127 Digester digester = new Digester();
128         digester.setEntityResolver(new EntityResolver JavaDoc(){
129             public InputSource JavaDoc resolveEntity(String JavaDoc publicId, String JavaDoc systemId)
130             {
131                 return new InputSource JavaDoc(getClass().getClassLoader().getResourceAsStream("properties.dtd"));
132             }
133         });
134
135         digester.addCallMethod("properties/comment", "setHeader", 0);
136
137         digester.addCallMethod("properties/entry", "addProperty", 2);
138         digester.addCallParam("properties/entry", 0, "key");
139         digester.addCallParam("properties/entry", 1);
140
141         // todo: support included properties ?
142
143         // parse the file
144 digester.push(this);
145         try
146         {
147             digester.parse(in);
148         }
149         catch (Exception JavaDoc e)
150         {
151             throw new ConfigurationException("Unable to parse the configuration file", e);
152         }
153     }
154
155     public void save(Writer JavaDoc out) throws ConfigurationException
156     {
157         PrintWriter JavaDoc writer = new PrintWriter JavaDoc(out);
158
159         String JavaDoc encoding = getEncoding() != null ? getEncoding() : DEFAULT_ENCODING;
160         writer.println("<?xml version=\"1.0\" encoding=\"" + encoding + "\"?>");
161         writer.println("<!DOCTYPE properties SYSTEM \"http://java.sun.com/dtd/properties.dtd\">");
162         writer.println("<properties>");
163
164         if (getHeader() != null)
165         {
166             writer.println(" <comment>" + StringEscapeUtils.escapeXml(getHeader()) + "</comment>");
167         }
168
169         Iterator JavaDoc keys = getKeys();
170         while (keys.hasNext())
171         {
172             String JavaDoc key = (String JavaDoc) keys.next();
173             Object JavaDoc value = getProperty(key);
174
175             if (value instanceof List JavaDoc)
176             {
177                 writeProperty(writer, key, (List JavaDoc) value);
178             }
179             else
180             {
181                 writeProperty(writer, key, value);
182             }
183         }
184
185         writer.println("</properties>");
186         writer.flush();
187     }
188
189     /**
190      * Write a property.
191      */
192     private void writeProperty(PrintWriter JavaDoc out, String JavaDoc key, Object JavaDoc value)
193     {
194         // escape the key
195 String JavaDoc k = StringEscapeUtils.escapeXml(key);
196
197         if (value != null)
198         {
199             // escape the value
200 String JavaDoc v = StringEscapeUtils.escapeXml(String.valueOf(value));
201             v = StringUtils.replace(v, String.valueOf(getDelimiter()), "\\" + getDelimiter());
202
203             out.println(" <entry key=\"" + k + "\">" + v + "</entry>");
204         }
205         else
206         {
207             out.println(" <entry key=\"" + k + "\"/>");
208         }
209     }
210
211     /**
212      * Write a list property.
213      */
214     private void writeProperty(PrintWriter JavaDoc out, String JavaDoc key, List JavaDoc values)
215     {
216         for (int i = 0; i < values.size(); i++)
217         {
218             writeProperty(out, key, values.get(i));
219         }
220     }
221 }
222
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