Source for gnu.java.locale.LocaleHelper

   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: }