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Java > Open Source Codes > org > jfree > util > SortedConfigurationWriter


1 /* ========================================================================
2  * JCommon : a free general purpose class library for the Java(tm) platform
3  * ========================================================================
4  *
5  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6  *
7  * Project Info: http://www.jfree.org/jcommon/index.html
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * ------------------------------
28  * SortedConfigurationWriter.java
29  * ------------------------------
30  * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
31  *
32  * Original Author: Thomas Morgner;
33  * Contributor(s): -;
34  *
35  * $Id: SortedConfigurationWriter.java,v 1.4 2005/11/03 09:55:27 mungady Exp $
36  *
37  * Changes
38  * -------
39  *
40  */
41
42 package org.jfree.util;
43
44 import java.io.BufferedOutputStream JavaDoc;
45 import java.io.File JavaDoc;
46 import java.io.FileOutputStream JavaDoc;
47 import java.io.IOException JavaDoc;
48 import java.io.OutputStream JavaDoc;
49 import java.io.OutputStreamWriter JavaDoc;
50 import java.io.Writer JavaDoc;
51 import java.util.ArrayList JavaDoc;
52 import java.util.Collections JavaDoc;
53 import java.util.Iterator JavaDoc;
54
55 /**
56  * Writes a <code>Configuration</code> instance into a property file, where
57  * the keys are sorted by their name. Writing sorted keys make it easier for
58  * users to find and change properties in the file.
59  *
60  * @author Thomas Morgner
61  */
62 public class SortedConfigurationWriter {
63     /**
64      * A constant defining that text should be escaped in a way
65      * which is suitable for property keys.
66      */
67     private static final int ESCAPE_KEY = 0;
68     /**
69      * A constant defining that text should be escaped in a way
70      * which is suitable for property values.
71      */
72     private static final int ESCAPE_VALUE = 1;
73     /**
74      * A constant defining that text should be escaped in a way
75      * which is suitable for property comments.
76      */
77     private static final int ESCAPE_COMMENT = 2;
78
79     /** The system-dependent End-Of-Line separator. */
80     private static final String JavaDoc END_OF_LINE = StringUtils.getLineSeparator();
81
82     /**
83      * The default constructor, does nothing.
84      */
85     public SortedConfigurationWriter() {
86     }
87
88     /**
89      * Returns a description for the given key. This implementation returns
90      * null to indicate that no description should be written. Subclasses can
91      * overwrite this method to provide comments for every key. These descriptions
92      * will be included as inline comments.
93      *
94      * @param key the key for which a description should be printed.
95      * @return the description or null if no description should be printed.
96      */
97     protected String JavaDoc getDescription(final String JavaDoc key) {
98         return null;
99     }
100
101     /**
102      * Saves the given configuration into a file specified by the given
103      * filename.
104      *
105      * @param filename the filename
106      * @param config the configuration
107      * @throws IOException if an IOError occurs.
108      */
109     public void save(final String JavaDoc filename, final Configuration config)
110         throws IOException JavaDoc {
111         save(new File JavaDoc(filename), config);
112     }
113
114     /**
115      * Saves the given configuration into a file specified by the given
116      * file object.
117      *
118      * @param file the target file
119      * @param config the configuration
120      * @throws IOException if an IOError occurs.
121      */
122     public void save(final File JavaDoc file, final Configuration config)
123         throws IOException JavaDoc {
124         final BufferedOutputStream JavaDoc out =
125             new BufferedOutputStream JavaDoc(new FileOutputStream JavaDoc(file));
126         save(out, config);
127         out.close();
128     }
129
130
131     /**
132      * Writes the configuration into the given output stream.
133      *
134      * @param outStream the target output stream
135      * @param config the configuration
136      * @throws IOException if writing fails.
137      */
138     public void save(final OutputStream JavaDoc outStream, final Configuration config)
139         throws IOException JavaDoc {
140         final ArrayList JavaDoc names = new ArrayList JavaDoc();
141
142         // clear all previously set configuration settings ...
143 final Iterator JavaDoc defaults = config.findPropertyKeys("");
144         while (defaults.hasNext()) {
145             final String JavaDoc key = (String JavaDoc) defaults.next();
146             names.add(key);
147         }
148
149         Collections.sort(names);
150
151         final OutputStreamWriter JavaDoc out =
152             new OutputStreamWriter JavaDoc(outStream, "iso-8859-1");
153
154         for (int i = 0; i < names.size(); i++) {
155             final String JavaDoc key = (String JavaDoc) names.get(i);
156             final String JavaDoc value = config.getConfigProperty(key);
157
158             final String JavaDoc description = getDescription(key);
159             if (description != null) {
160                 writeDescription(description, out);
161             }
162             saveConvert(key, ESCAPE_KEY, out);
163             out.write("=");
164             saveConvert(value, ESCAPE_VALUE, out);
165             out.write(END_OF_LINE);
166         }
167         out.flush();
168
169     }
170
171     /**
172      * Writes a descriptive comment into the given print writer.
173      *
174      * @param text the text to be written. If it contains more than
175      * one line, every line will be prepended by the comment character.
176      * @param writer the writer that should receive the content.
177      * @throws IOException if writing fails
178      */
179     private void writeDescription(final String JavaDoc text, final Writer JavaDoc writer)
180         throws IOException JavaDoc {
181         // check if empty content ... this case is easy ...
182 if (text.length() == 0) {
183             return;
184         }
185
186         writer.write("# ");
187         writer.write(END_OF_LINE);
188         final LineBreakIterator iterator = new LineBreakIterator(text);
189         while (iterator.hasNext()) {
190             writer.write("# ");
191             saveConvert((String JavaDoc) iterator.next(), ESCAPE_COMMENT, writer);
192             writer.write(END_OF_LINE);
193         }
194     }
195
196     /**
197      * Performs the necessary conversion of an java string into a property
198      * escaped string.
199      *
200      * @param text the text to be escaped
201      * @param escapeMode the mode that should be applied.
202      * @param writer the writer that should receive the content.
203      * @throws IOException if writing fails
204      */
205     private void saveConvert(final String JavaDoc text, final int escapeMode,
206                              final Writer JavaDoc writer)
207         throws IOException JavaDoc {
208         final char[] string = text.toCharArray();
209
210         for (int x = 0; x < string.length; x++) {
211             final char aChar = string[x];
212             switch (aChar) {
213                 case ' ':
214                     {
215                         if ((escapeMode != ESCAPE_COMMENT)
216                                 && (x == 0 || escapeMode == ESCAPE_KEY)) {
217                             writer.write('\\');
218                         }
219                         writer.write(' ');
220                         break;
221                     }
222                 case '\\':
223                     {
224                         writer.write('\\');
225                         writer.write('\\');
226                         break;
227                     }
228                 case '\t':
229                     {
230                         if (escapeMode == ESCAPE_COMMENT) {
231                             writer.write(aChar);
232                         }
233                         else {
234                             writer.write('\\');
235                             writer.write('t');
236                         }
237                         break;
238                     }
239                 case '\n':
240                     {
241                         writer.write('\\');
242                         writer.write('n');
243                         break;
244                     }
245                 case '\r':
246                     {
247                         writer.write('\\');
248                         writer.write('r');
249                         break;
250                     }
251                 case '\f':
252                     {
253                         if (escapeMode == ESCAPE_COMMENT) {
254                             writer.write(aChar);
255                         }
256                         else {
257                             writer.write('\\');
258                             writer.write('f');
259                         }
260                         break;
261                     }
262                 case '#':
263                 case '"':
264                 case '!':
265                 case '=':
266                 case ':':
267                     {
268                         if (escapeMode == ESCAPE_COMMENT) {
269                             writer.write(aChar);
270                         }
271                         else {
272                             writer.write('\\');
273                             writer.write(aChar);
274                         }
275                         break;
276                     }
277                 default:
278                     if ((aChar < 0x0020) || (aChar > 0x007e)) {
279                         writer.write('\\');
280                         writer.write('u');
281                         writer.write(HEX_CHARS[(aChar >> 12) & 0xF]);
282                         writer.write(HEX_CHARS[(aChar >> 8) & 0xF]);
283                         writer.write(HEX_CHARS[(aChar >> 4) & 0xF]);
284                         writer.write(HEX_CHARS[aChar & 0xF]);
285                     }
286                     else {
287                         writer.write(aChar);
288                     }
289             }
290         }
291     }
292
293     /** A lookup-table. */
294     private static final char[] HEX_CHARS =
295         {'0', '1', '2', '3', '4', '5', '6', '7',
296          '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
297 }
298
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