Messages


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   * $Id: Messages.java,v 1.1.4.1 2005/09/08 11:03:10 suresh_emailid Exp $
18   */
19  package com.sun.org.apache.xml.internal.serializer.utils;
20  
21  import java.util.ListResourceBundle  ;
22  import java.util.Locale  ;
23  import java.util.MissingResourceException  ;
24  import java.util.ResourceBundle  ;
25  
26  /**
27   * A utility class for issuing error messages.
28   * 
29   * A user of this class normally would create a singleton 
30   * instance of this class, passing the name
31   * of the message class on the constructor. For example:
32   * <CODE>
33   * static Messages x = new Messages("org.package.MyMessages");
34   * </CODE>
35   * Later the message is typically generated this way if there are no 
36   * substitution arguments:
37   * <CODE>
38   * String msg = x.createMessage(org.package.MyMessages.KEY_ONE, null); 
39   * </CODE>
40   * If there are arguments substitutions then something like this:
41   * <CODE>
42   * String filename = ...;
43   * String directory = ...;
44   * String msg = x.createMessage(org.package.MyMessages.KEY_TWO, 
45   *   new Object[] {filename, directory) ); 
46   * </CODE>
47   *  
48   * The constructor of an instance of this class must be given
49   * the class name of a class that extends java.util.ListResourceBundle 
50   * ("org.package.MyMessages" in the example above).  
51   * The name should not have any language suffix 
52   * which will be added automatically by this utility class.
53   * 
54   * The message class ("org.package.MyMessages")
55   * must define the abstract method getContents() that is
56   * declared in its base class, for example:
57   * <CODE>
58   * public Object[][] getContents() {return contents;}
59   * </CODE>
60   * 
61   * It is suggested that the message class expose its
62   * message keys like this:
63   * <CODE>
64   *   public static final String KEY_ONE = "KEY1";
65   *   public static final String KEY_TWO = "KEY2";
66   *   . . . 
67   * </CODE>
68   * and used through their names (KEY_ONE ...) rather than
69   * their values ("KEY1" ...).
70   * 
71   * The field contents (returned by getContents()
72   * should be initialized something like this:
73   * <CODE>
74   * public static final Object[][] contents = {
75   * { KEY_ONE, "Something has gone wrong!" },
76   * { KEY_TWO, "The file ''{0}'' does not exist in directory ''{1}''." },
77   * . . .
78   * { KEY_N, "Message N" }  }
79   * </CODE>
80   * 
81   * Where that section of code with the KEY to Message mappings
82   * (where the message classes 'contents' field is initialized)
83   * can have the Message strings translated in an alternate language
84   * in a errorResourceClass with a language suffix.
85   * 
86   * More sophisticated use of this class would be to pass null
87   * when contructing it, but then call loadResourceBundle()
88   * before creating any messages.
89   * 
90   * This class is not a public API, it is only public because it is 
91   * used in com.sun.org.apache.xml.internal.serializer.
92   *
93   *  @xsl.usage internal
94   */
95  public final class Messages
96  {
97      /** The local object to use.  */
98      private final Locale   m_locale = Locale.getDefault();
99  
100     /** The language specific resource object for messages.  */
101     private ListResourceBundle   m_resourceBundle;
102 
103     /** The class name of the error message string table with no language suffix. */
104     private String   m_resourceBundleName;
105 
106 
107 
108     /**
109      * Constructor.
110      * @param resourceBundle the class name of the ListResourceBundle
111      * that the instance of this class is associated with and will use when
112      * creating messages.
113      * The class name is without a language suffix. If the value passed
114      * is null then loadResourceBundle(errorResourceClass) needs to be called
115      * explicitly before any messages are created.
116      * 
117      * @xsl.usage internal
118      */
119     Messages(String   resourceBundle)
120     {
121 
122         m_resourceBundleName = resourceBundle;
123     }
124     
125     /*
126      * Set the Locale object to use. If this method is not called the
127      * default locale is used. This method needs to be called before
128      * loadResourceBundle().
129      * 
130      * @param locale non-null reference to Locale object.
131      * @xsl.usage internal
132      */
133 //    public void setLocale(Locale locale)
134 //    {
135 //        m_locale = locale;
136 //    }
137 
138     /**
139      * Get the Locale object that is being used.
140      * 
141      * @return non-null reference to Locale object.
142      * @xsl.usage internal
143      */
144     private Locale   getLocale()
145     {
146         return m_locale;
147     }
148 
149     /**
150      * Get the ListResourceBundle being used by this Messages instance which was
151      * previously set by a call to loadResourceBundle(className)
152      * @xsl.usage internal
153      */
154     private ListResourceBundle   getResourceBundle()
155     {
156         return m_resourceBundle;
157     }
158 
159     /**
160      * Creates a message from the specified key and replacement
161      * arguments, localized to the given locale.
162      *
163      * @param msgKey  The key for the message text.
164      * @param args    The arguments to be used as replacement text
165      * in the message created.
166      *
167      * @return The formatted message string.
168      * @xsl.usage internal
169      */
170     public final String   createMessage(String   msgKey, Object   args[])
171     {
172         if (m_resourceBundle == null)
173             m_resourceBundle = loadResourceBundle(m_resourceBundleName);
174 
175         if (m_resourceBundle != null)
176         {
177             return createMsg(m_resourceBundle, msgKey, args);
178         }
179         else
180             return "Could not load the resource bundles: "+ m_resourceBundleName;
181     }
182 
183     /**
184      * Creates a message from the specified key and replacement
185      * arguments, localized to the given locale.
186      *
187      * @param errorCode The key for the message text.
188      *
189      * @param fResourceBundle The resource bundle to use.
190      * @param msgKey  The message key to use.
191      * @param args      The arguments to be used as replacement text
192      *                  in the message created.
193      *
194      * @return The formatted message string.
195      * @xsl.usage internal
196      */
197     private final String   createMsg(
198         ListResourceBundle   fResourceBundle,
199         String   msgKey,
200         Object   args[]) //throws Exception
201     {
202 
203         String   fmsg = null;
204         boolean throwex = false;
205         String   msg = null;
206 
207         if (msgKey != null)
208             msg = fResourceBundle.getString(msgKey);
209         else
210             msgKey = "";
211 
212         if (msg == null)
213         {
214             throwex = true;
215             /* The message is not in the bundle . . . this is bad,
216              * so try to get the message that the message is not in the bundle
217              */
218             try
219             {
220 
221                 msg =
222                     java.text.MessageFormat.format(
223                         MsgKey.BAD_MSGKEY,
224                         new Object  [] { msgKey, m_resourceBundleName });
225             }
226             catch (Exception   e)
227             {
228                 /* even the message that the message is not in the bundle is
229                  * not there ... this is really bad
230                  */
231                 msg =
232                     "The message key '"
233                         + msgKey
234                         + "' is not in the message class '"
235                         + m_resourceBundleName+"'";
236             }
237         }
238         else if (args != null)
239         {
240             try
241             {
242                 // Do this to keep format from crying.
243                 // This is better than making a bunch of conditional
244                 // code all over the place.
245                 int n = args.length;
246 
247                 for (int i = 0; i < n; i++)
248                 {
249                     if (null == args[i])
250                         args[i] = "";
251                 }
252 
253                 fmsg = java.text.MessageFormat.format(msg, args);
254                 // if we get past the line above we have create the message ... hurray!
255             }
256             catch (Exception   e)
257             {
258                 throwex = true;
259                 try
260                 {
261                     // Get the message that the format failed.
262                     fmsg =
263                         java.text.MessageFormat.format(
264                             MsgKey.BAD_MSGFORMAT,
265                             new Object  [] { msgKey, m_resourceBundleName });
266                     fmsg += " " + msg;
267                 }
268                 catch (Exception   formatfailed)
269                 {
270                     // We couldn't even get the message that the format of
271                     // the message failed ... so fall back to English.
272                     fmsg =
273                         "The format of message '"
274                             + msgKey
275                             + "' in message class '"
276                             + m_resourceBundleName
277                             + "' failed.";
278                 }
279             }
280         }
281         else
282             fmsg = msg;
283 
284         if (throwex)
285         {
286             throw new RuntimeException  (fmsg);
287         }
288 
289         return fmsg;
290     }
291 
292     /**
293      * Return a named ResourceBundle for a particular locale.  This method mimics the behavior
294      * of ResourceBundle.getBundle().
295      * 
296      * @param className the name of the class that implements ListResourceBundle,
297      * without language suffix.
298      * @return the ResourceBundle
299      * @throws MissingResourceException
300      * @xsl.usage internal
301      */
302     private ListResourceBundle   loadResourceBundle(String   resourceBundle)
303         throws MissingResourceException  
304     {
305         m_resourceBundleName = resourceBundle;
306         Locale   locale = getLocale();
307 
308         ListResourceBundle   lrb;
309 
310         try
311         {
312 
313             ResourceBundle   rb =
314                 ResourceBundle.getBundle(m_resourceBundleName, locale);
315             lrb = (ListResourceBundle  ) rb;
316         }
317         catch (MissingResourceException   e)
318         {
319             try // try to fall back to en_US if we can't load
320                 {
321 
322                 // Since we can't find the localized property file,
323                 // fall back to en_US.
324                 lrb =
325                     (ListResourceBundle  ) ResourceBundle.getBundle(
326                         m_resourceBundleName,
327                         new Locale  ("en", "US"));
328             }
329             catch (MissingResourceException   e2)
330             {
331 
332                 // Now we are really in trouble.
333                 // very bad, definitely very bad...not going to get very far
334                 throw new MissingResourceException  (
335                     "Could not load any resource bundles." + m_resourceBundleName,
336                     m_resourceBundleName,
337                     "");
338             }
339         }
340         m_resourceBundle = lrb;
341         return lrb;
342     }
343 
344     /**
345      * Return the resource file suffic for the indicated locale
346      * For most locales, this will be based the language code.  However
347      * for Chinese, we do distinguish between Taiwan and PRC
348      *
349      * @param locale the locale
350      * @return an String suffix which can be appended to a resource name
351      * @xsl.usage internal
352      */
353     private static String   getResourceSuffix(Locale   locale)
354     {
355 
356         String   suffix = "_" + locale.getLanguage();
357         String   country = locale.getCountry();
358 
359         if (country.equals("TW"))
360             suffix += "_" + country;
361 
362         return suffix;
363     }
364 }
365
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