gomp-20050608-branch/libjava/classpath/gnu/java/locale/LocaleHelper.java

   1 /* LocaleHelper.java -- helper routines for localization
   2    Copyright (C) 2004, 2005 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package gnu.java.locale;
  40
  41 import java.util.Locale;
  42 import java.util.MissingResourceException;
  43 import java.util.ResourceBundle;
  44
  45 /**
  46  * This class provides common helper methods
  47  * for handling localized data.
  48  *
  49  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  50  *
  51  * @see java.util.Locale
  52  * @see java.util.ResourceBundle
  53  */
  54 public class LocaleHelper
  55 {
  56   /**
  57    * This method is used by the localized name lookup methods to retrieve
  58    * the localized name of a particular piece of locale data.
  59    * If the display name can not be localized to the supplied
  60    * locale, it will fall back on other output in the following order:
  61    *
  62    * <ul>
  63    * <li>the localized name in the default locale</li>
  64    * <li>the localized name in English (optional)</li>
  65    * <li>the localized name in the root locale bundle (optional)</li>
  66    * <li>the localized input string</li>
  67    * </ul>
  68    * <p>
  69    * If the supplied key is merely the empty string, then the empty string is
  70    * returned.
  71    * </p>
  72    *
  73    * @param inLocale the locale to use for formatting the display string.
  74    * @param key the locale data used as a key to the localized lookup tables.
  75    * @param name the name of the hashtable containing the localized data.
  76    * @param checkEnglish true if the method should fall back on data
  77    *        from the English locale.
  78    * @param checkRoot true if the method should fall back on data from the
  79    *        unlocalized root locale.
  80    * @return a <code>String</code>, hopefully containing the localized
  81    *         variant of the input data.
  82    * @throws NullPointerException if <code>inLocale</code> is null.
  83    */
  84   public static String getLocalizedString(Locale inLocale, String key,
  85                                           String name, boolean checkEnglish,
  86                                           boolean checkRoot)
  87   {
  88     String localizedString;
  89     String property;
  90
  91     if (key.equals(""))
  92       return "";
  93     property = name + "." + key;
  94     /* Localize to inLocale */
  95     try
  96       {
  97         localizedString =
  98           ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
  99                                    inLocale).getString(property);
 100       }
 101     catch (MissingResourceException exception)
 102       {
 103         localizedString = null;
 104       }
 105     /* Localize to default locale */
 106     if (localizedString == null)
 107       {
 108         try
 109           {
 110             ResourceBundle bundle;
 111
 112             bundle =
 113               ResourceBundle.getBundle("gnu.java.locale.LocaleInformation");
 114             localizedString = bundle.getString(property);
 115           }
 116         catch (MissingResourceException exception)
 117           {
 118             localizedString = null;
 119           }
 120       }
 121     /* Localize to English */
 122     if (localizedString == null && checkEnglish)
 123       {
 124         try
 125           {
 126             localizedString =
 127               ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
 128                                        Locale.ENGLISH).getString(property);
 129           }
 130         catch (MissingResourceException exception)
 131           {
 132             localizedString = null;
 133           }
 134       }
 135     /* Return unlocalized version */
 136     if (localizedString == null && checkRoot)
 137       {
 138         try
 139           {
 140             localizedString =
 141               ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
 142                                        new Locale("","","")
 143                                        ).getString(property);
 144           }
 145         catch (MissingResourceException exception)
 146           {
 147             localizedString = null;
 148           }
 149       }
 150     /* Return original input string */
 151     if (localizedString == null)
 152       {
 153         localizedString = key;
 154       }
 155     return localizedString;
 156   }
 157 }
 158