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.text.Collator;
  42 import java.util.Locale;
  43 import java.util.MissingResourceException;
  44 import java.util.ResourceBundle;
  45
  46 /**
  47  * This class provides common helper methods
  48  * for handling localized data.
  49  *
  50  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  51  *
  52  * @see java.util.Locale
  53  * @see java.util.ResourceBundle
  54  */
  55 public class LocaleHelper
  56 {
  57   /**
  58    * This method is used by the localized name lookup methods to retrieve
  59    * the localized name of a particular piece of locale data.
  60    * If the display name can not be localized to the supplied
  61    * locale, it will fall back on other output in the following order:
  62    *
  63    * <ul>
  64    * <li>the localized name in the default locale</li>
  65    * <li>the localized name in English (optional)</li>
  66    * <li>the localized name in the root locale bundle (optional)</li>
  67    * <li>the localized input string</li>
  68    * </ul>
  69    * <p>
  70    * If the supplied key is merely the empty string, then the empty string is
  71    * returned.
  72    * </p>
  73    *
  74    * @param inLocale the locale to use for formatting the display string.
  75    * @param key the locale data used as a key to the localized lookup tables.
  76    * @param name the name of the hashtable containing the localized data.
  77    * @param checkEnglish true if the method should fall back on data
  78    *        from the English locale.
  79    * @param checkRoot true if the method should fall back on data from the
  80    *        unlocalized root locale.
  81    * @return a <code>String</code>, hopefully containing the localized
  82    *         variant of the input data.
  83    * @throws NullPointerException if <code>inLocale</code> is null.
  84    */
  85   public static String getLocalizedString(Locale inLocale, String key,
  86                                           String name, boolean checkEnglish,
  87                                           boolean checkRoot)
  88   {
  89     String localizedString;
  90     String property;
  91
  92     if (key.equals(""))
  93       return "";
  94     property = name + "." + key;
  95     /* Localize to inLocale */
  96     try
  97       {
  98         localizedString =
  99           ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
 100                                    inLocale).getString(property);
 101       }
 102     catch (MissingResourceException exception)
 103       {
 104         localizedString = null;
 105       }
 106     /* Localize to default locale */
 107     if (localizedString == null)
 108       {
 109         try
 110           {
 111             ResourceBundle bundle;
 112
 113             bundle =
 114               ResourceBundle.getBundle("gnu.java.locale.LocaleInformation");
 115             localizedString = bundle.getString(property);
 116           }
 117         catch (MissingResourceException exception)
 118           {
 119             localizedString = null;
 120           }
 121       }
 122     /* Localize to English */
 123     if (localizedString == null && checkEnglish)
 124       {
 125         try
 126           {
 127             localizedString =
 128               ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
 129                                        Locale.ENGLISH).getString(property);
 130           }
 131         catch (MissingResourceException exception)
 132           {
 133             localizedString = null;
 134           }
 135       }
 136     /* Return unlocalized version */
 137     if (localizedString == null && checkRoot)
 138       {
 139         try
 140           {
 141             localizedString =
 142               ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
 143                                        new Locale("","","")
 144                                        ).getString(property);
 145           }
 146         catch (MissingResourceException exception)
 147           {
 148             localizedString = null;
 149           }
 150       }
 151     /* Return original input string */
 152     if (localizedString == null)
 153       {
 154         localizedString = key;
 155       }
 156     return localizedString;
 157   }
 158
 159   /**
 160    * Return an array of all the locales for which there is a
 161    * {@link Collator} instance.  A new array is returned each time.
 162    */
 163   public static Locale[] getCollatorLocales()
 164   {
 165     // For now we don't bother caching.  This is probably
 166     // not called very frequently.  And, we would have to
 167     // clone the array anyway.
 168     if (LocaleData.collatorLocaleNames.length == 0)
 169       return new Locale[] { Locale.US };
 170     Locale[] result = new Locale[LocaleData.collatorLocaleNames.length];
 171     for (int i = 0; i < result.length; ++i)
 172       {
 173         String language;
 174         String region = "";
 175         String variant = "";
 176         String name = LocaleData.collatorLocaleNames[i];
 177
 178         language = name.substring(0, 2);
 179
 180         if (name.length() > 2)
 181           region = name.substring(3);
 182
 183         int index = region.indexOf("_");
 184         if (index > 0)
 185           {
 186             variant = region.substring(index + 1);
 187             region = region.substring(0, index - 1);
 188           }
 189
 190         result[i] = new Locale(language, region, variant);
 191       }
 192     return result;
 193   }
 194
 195   /**
 196    * Return the number of locales we know of.
 197    */
 198   public static int getLocaleCount()
 199   {
 200     return LocaleData.localeNames.length;
 201   }
 202
 203   /**
 204    * Return the Nth locale name.
 205    */
 206   public static String getLocaleName(int n)
 207   {
 208     return LocaleData.localeNames[n];
 209   }
 210 }
 211