JDOMAbout


1   /*-- 
2   
3    Copyright (C) 2001-2004 Jason Hunter & Brett McLaughlin.
4    All rights reserved.
5    
6    Redistribution and use in source and binary forms, with or without
7    modification, are permitted provided that the following conditions
8    are met:
9    
10   1. Redistributions of source code must retain the above copyright
11      notice, this list of conditions, and the following disclaimer.
12   
13   2. Redistributions in binary form must reproduce the above copyright
14      notice, this list of conditions, and the disclaimer that follows 
15      these conditions in the documentation and/or other materials 
16      provided with the distribution.
17  
18   3. The name "JDOM" must not be used to endorse or promote products
19      derived from this software without prior written permission.  For
20      written permission, please contact license@jdom.org.
21   
22   4. Products derived from this software may not be called "JDOM", nor
23      may "JDOM" appear in their name, without prior written permission
24      from the JDOM Project Management (pm@jdom.org).
25   
26   In addition, we request (but do not require) that you include in the 
27   end-user documentation provided with the redistribution and/or in the 
28   software itself an acknowledgement equivalent to the following:
29       "This product includes software developed by the
30        JDOM Project (http://www.jdom.org/)."
31   Alternatively, the acknowledgment may be graphical using the logos 
32   available at http://www.jdom.org/images/logos.
33  
34   THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
35   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
36   OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
37   DISCLAIMED.  IN NO EVENT SHALL THE JDOM AUTHORS OR THE PROJECT
38   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
41   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
42   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
43   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
44   OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
45   SUCH DAMAGE.
46  
47   This software consists of voluntary contributions made by many 
48   individuals on behalf of the JDOM Project and was originally 
49   created by Jason Hunter <jhunter_AT_jdom_DOT_org> and
50   Brett McLaughlin <brett_AT_jdom_DOT_org>.  For more information
51   on the JDOM Project, please see <http://www.jdom.org/>.
52  
53   */
54  
55  // Explicitly left in the default package
56  
57  import java.io.*;
58  import java.util.*;
59  import java.util.jar.*;
60  import java.util.zip.*;
61  
62  import org.jdom.*;
63  import org.jdom.input.*;
64  
65  /**
66   * This class is not part of the core JDOM API, but implements the main
67   * method executed when the JDOM JAR is invoked directly. For example,
68   * to "run" the JDOM JAR directly use a command line such as the following:
69   *
70   * <pre>
71   *   java -jar jdom.jar
72   * </pre>
73   *
74   * When run like this, the output will display product and version
75   * information, a brief description of JDOM and the authors, all as
76   * specified in the file META-INF/info.xml contained within the JAR.
77   * If this file does not exist in the JAR, then the JAR has been
78   * incorrectly built.  Any exceptions will pop the call stack and end the
79   * program with a message describing the error.
80   *
81   * @see http://java.sun.com/docs/books/tutorial/jar/
82   *
83   * @author Steven Gould <steven.gouldATcgiusa.com>
84   */
85  public class JDOMAbout {
86      /**
87       * The main(!) method executed when this JAR file is run. Outputs
88       * information about the JAR, as extracted from the META-INF/info.xml
89       * file.
90       * @param args Ignored. 
91       */
92      public static void main(String   args[]) throws Exception   {
93          JDOMAbout.Info info = new JDOMAbout().new Info();
94  
95          // Shortcut for info.title (because it's used so much)
96          String   title = info.title;
97  
98          // Output product information
99          System.out.println(title + " version " + info.version);
100         System.out.println("Copyright " + info.copyright);
101         System.out.println();
102         
103         // Display product/JAR "description"
104         System.out.println(info.description);
105         System.out.println();
106         
107         // Iterate through authors, outputting each in turn
108         System.out.println("Authors:");
109         Iterator it = info.authors.iterator();
110         while (it.hasNext()) {
111             Author author = (Author)it.next();
112         
113             // Output the author's name
114             System.out.print("  " + author.name);
115                 
116             // If the author has an e-mail address, output it too
117             if (author.email == null) {
118                 System.out.println();
119             } else {
120                 System.out.println(" <" + author.email + ">");
121             }
122         }
123         System.out.println();
124     
125         // Display "license" information
126         System.out.println(title + " license:");
127         System.out.println(info.license);
128         System.out.println();
129     
130         // Display "support" information
131         System.out.println(title + " support:");
132         System.out.println(info.support);
133         System.out.println();
134     
135         // Display "license" information
136         System.out.println(title + " web site: " + info.website);
137         System.out.println();
138     }
139 
140     /**
141      * This class encapsulates the locating of, and reading of, the JAR
142      * information file. This file should be named META-INF/info.xml. The
143      * default constructor initializes all members variables from the
144      * content of the info.xml file.
145      *
146      * <p>This class has been separated out for a couple of reasons:
147      * <ol>
148      *  <li>So that the presentation of the data in info.xml can be
149      *      separated out from the reading of the file - enabling a "looser"
150      *      coupling between the data and presentation.</li>
151      *  <li>Just in case we later decide to make this information
152      *      publically accessible. If this happens we'll probably want to
153      *      implement "get" methods for each of the member variables. For
154      *      now, it was decided that doing so may be too much of an overhead
155      *      for an internal class.</li>
156      * </ol>
157      */
158     private class Info {
159         /** The product title, or product name. */
160         String   title;
161 
162         /**
163          * The product/JAR version number - or string. This can contain
164          * characters.
165          */
166         String   version;
167 
168         /** The JAR copyright message. */
169         String   copyright;
170 
171         /** A description of the contents of this JAR. */
172         String   description;
173 
174         /** A list of authors of this product/JAR. */
175         List authors;
176 
177         /** The product/JAR license information. */
178         String   license;
179 
180         /** Product/JAR support information. */
181         String   support;
182 
183         /** The main web site for this product/JAR. */
184         String   website;
185     
186         /**
187          * Constructor for the Info class - initializes all member
188          * variables with values taken from the JAR information file.
189          * The JAR information file should be called META-INF/info.xml
190          * and be contained within the JAR file.
191          * Any exceptions are passed to the caller.
192          */
193         Info() throws Exception   {
194             final String   INFO_FILENAME = "META-INF/info.xml";
195 
196             SAXBuilder builder = new SAXBuilder();
197         
198             // Find the INFO_FILENAME file in any JAR in the classpath
199             // Use a brute-force search
200             JarFile jarFile = null;
201             ZipEntry zipEntry = null;
202 
203             String   classpath = System.getProperty("java.class.path");
204             StringTokenizer tokenizer = new StringTokenizer(classpath, ";:");
205             while (tokenizer.hasMoreTokens() && zipEntry == null) {
206               String   token = tokenizer.nextToken();
207 
208               try {
209                 // Try to create a JarFile representation of the JAR
210                 jarFile = new JarFile(token);
211             
212                 // Get a reference to the info.xml entry in the JAR
213                 zipEntry = jarFile.getEntry(INFO_FILENAME);
214               }
215               catch (Exception   e) {
216               }
217             }
218             
219             if (zipEntry == null) {
220               throw new FileNotFoundException(INFO_FILENAME + 
221                 " not found; it should be within the JDOM JAR but isn't");
222             }
223 
224             // Get input stream for reading info.xml file
225             InputStream in = jarFile.getInputStream(zipEntry);
226             
227             // Using JDOM, read the info.xml file
228             Document doc = builder.build(in);
229             Element root = doc.getRootElement();
230 
231             title = root.getChildTextTrim("title");
232             version = root.getChildTextTrim("version");
233             copyright = root.getChildTextTrim("copyright");
234             description = root.getChildTextTrim("description");
235             license = root.getChildTextTrim("license");
236             support = root.getChildTextTrim("support");
237             website = root.getChildTextTrim("web-site");
238 
239             List authorElements = root.getChildren("author");
240             authors = new LinkedList();
241             Iterator it = authorElements.iterator();
242             while (it.hasNext()) {
243                 Element element = (Element)it.next();
244                     
245                 Author author = new Author();
246                 author.name = element.getChildTextTrim("name");
247                 author.email = element.getChildTextTrim("e-mail");
248 
249                 authors.add(author);
250             }
251         }
252     }
253 
254     /**
255      * A helper class that stores information about a single Author. By
256      * using this class, the Info class can store Author information
257      * without any dependence on JDOM and XML elements.
258      */
259     private class Author {
260         /** The name of this author. */
261         String   name;
262 
263         /** The e-mail address of this author. */
264         String   email;
265     }
266 }
267
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags