src/net/pterodactylus/util/i18n/I18n.java

   1 /*
   2  * jSite2 - I18n.java -
   3  * Copyright © 2008 David Roden
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  */
  19
  20 package net.pterodactylus.util.i18n;
  21
  22 import java.awt.event.InputEvent;
  23 import java.awt.event.KeyEvent;
  24 import java.io.IOException;
  25 import java.io.InputStream;
  26 import java.lang.reflect.Field;
  27 import java.text.MessageFormat;
  28 import java.util.ArrayList;
  29 import java.util.List;
  30 import java.util.Locale;
  31 import java.util.MissingResourceException;
  32 import java.util.Properties;
  33 import java.util.StringTokenizer;
  34 import java.util.logging.Level;
  35 import java.util.logging.Logger;
  36
  37 import javax.swing.KeyStroke;
  38
  39 import net.pterodactylus.util.logging.Logging;
  40 import de.ina.util.io.Closer;
  41
  42 /**
  43  * Class that handles i18n.
  44  *
  45  * @author David ‘Bombe’ Roden &lt;bombe@freenetproject.org&gt;
  46  */
  47 public class I18n {
  48
  49         /** Logger. */
  50         private static final Logger logger = Logging.getLogger(I18n.class.getName());
  51
  52         /** The base name of the resource files. */
  53         private String resourceName;
  54
  55         /** The class whose class loader is used to load resource files. */
  56         private final Class<?> resourceClass;
  57
  58         /** List of I18nables that are notified when the language changes. */
  59         private final List<I18nable> i18nables = new ArrayList<I18nable>();
  60
  61         /** The current locale. */
  62         private Locale currentLocale;
  63
  64         /** The default language. */
  65         private Properties defaultLanguage;
  66
  67         /** The current language. */
  68         private Properties currentLanguage;
  69
  70         /**
  71          * Creates a new I18n container.
  72          *
  73          * @param resourceName
  74          *            The base name of the language resource files
  75          * @param resourceClass
  76          *            The class whose class loader is used to load resource files
  77          */
  78         public I18n(String resourceName, Class<?> resourceClass) {
  79                 this.resourceName = resourceName;
  80                 this.resourceClass = resourceClass;
  81                 defaultLanguage = new Properties();
  82                 InputStream inputStream = null;
  83                 try {
  84                         inputStream = resourceClass.getResourceAsStream(resourceName + ".properties");
  85                         if (inputStream != null) {
  86                                 defaultLanguage.load(inputStream);
  87                         }
  88                 } catch (IOException e) {
  89                         /* something is fucked. */
  90                 }
  91                 setLocale(Locale.getDefault(), false);
  92         }
  93
  94         /**
  95          * Returns the translated value for a key. The translated values may contain
  96          * placeholders that are replaced with the given parameters.
  97          *
  98          * @see MessageFormat
  99          * @param key
 100          *            The key to get
 101          * @param parameters
 102          *            The parameters in case the translated value contains
 103          *            placeholders
 104          * @return The translated message, or the key itself if no translation could
 105          *         be found
 106          */
 107         public String get(String key, Object... parameters) {
 108                 String value = null;
 109                 value = currentLanguage.getProperty(key);
 110                 if (value == null) {
 111                         logger.log(Level.WARNING, "please fix “" + key + "”!", new Throwable());
 112                         /* TODO - replace with value when done! */
 113                         return null;
 114                 }
 115                 if ((parameters != null) && (parameters.length > 0)) {
 116                         return MessageFormat.format(value, parameters);
 117                 }
 118                 return value;
 119         }
 120
 121         /**
 122          * Returns the keycode from the value of the given key. You can specify the
 123          * constants in {@link KeyEvent} in the properties file, e.g. VK_S for the
 124          * keycode ‘s’ when used for mnemonics.
 125          *
 126          * @param key
 127          *            The key under which the keycode is stored
 128          * @return The keycode
 129          */
 130         public int getKey(String key) {
 131                 String value = currentLanguage.getProperty(key);
 132                 if ((value != null) && value.startsWith("VK_")) {
 133                         try {
 134                                 Field field = KeyEvent.class.getField(value);
 135                                 return field.getInt(null);
 136                         } catch (SecurityException e) {
 137                                 /* ignore. */
 138                         } catch (NoSuchFieldException e) {
 139                                 /* ignore. */
 140                         } catch (IllegalArgumentException e) {
 141                                 /* ignore. */
 142                         } catch (IllegalAccessException e) {
 143                                 /* ignore. */
 144                         }
 145                 }
 146                 System.err.println("please fix “" + key + "”!");
 147                 return KeyEvent.VK_UNDEFINED;
 148         }
 149
 150         /**
 151          * Returns a key stroke for use with swing accelerators.
 152          *
 153          * @param key
 154          *            The key of the key stroke
 155          * @return The key stroke, or <code>null</code> if no key stroke could be
 156          *         created from the translated value
 157          */
 158         public KeyStroke getKeyStroke(String key) {
 159                 String value = currentLanguage.getProperty(key);
 160                 if (value == null) {
 161                         return null;
 162                 }
 163                 StringTokenizer keyTokens = new StringTokenizer(value, "+- ");
 164                 int modifierMask = 0;
 165                 while (keyTokens.hasMoreTokens()) {
 166                         String keyToken = keyTokens.nextToken();
 167                         if ("ctrl".equalsIgnoreCase(keyToken)) {
 168                                 modifierMask |= InputEvent.CTRL_DOWN_MASK;
 169                         } else if ("alt".equalsIgnoreCase(keyToken)) {
 170                                 modifierMask |= InputEvent.ALT_DOWN_MASK;
 171                         } else if ("shift".equalsIgnoreCase(keyToken)) {
 172                                 modifierMask |= InputEvent.SHIFT_DOWN_MASK;
 173                         } else {
 174                                 if (keyToken.startsWith("VK_")) {
 175                                         if (keyToken.equals("VK_UNDEFINED")) {
 176                                                 return null;
 177                                         }
 178                                         try {
 179                                                 Field field = KeyEvent.class.getField(keyToken);
 180                                                 return KeyStroke.getKeyStroke(field.getInt(null), modifierMask);
 181                                         } catch (SecurityException e) {
 182                                                 /* ignore. */
 183                                         } catch (NoSuchFieldException e) {
 184                                                 /* ignore. */
 185                                         } catch (IllegalArgumentException e) {
 186                                                 /* ignore. */
 187                                         } catch (IllegalAccessException e) {
 188                                                 /* ignore. */
 189                                         }
 190                                 }
 191                                 return KeyStroke.getKeyStroke(keyToken.charAt(0), modifierMask);
 192                         }
 193                 }
 194                 return null;
 195         }
 196
 197         /**
 198          * Sets the current locale.
 199          *
 200          * @param newLocale
 201          *            The new locale to use
 202          */
 203         public void setLocale(Locale newLocale) {
 204                 setLocale(newLocale, true);
 205         }
 206
 207         /**
 208          * Sets the current locale.
 209          *
 210          * @param newLocale
 211          *            The new locale to use
 212          * @param notify
 213          *            <code>true</code> to notify registered {@link I18nable}s after
 214          *            the language was changed
 215          */
 216         private void setLocale(Locale newLocale, boolean notify) {
 217                 currentLocale = newLocale;
 218                 InputStream inputStream = null;
 219                 try {
 220                         currentLanguage = new Properties(defaultLanguage);
 221                         if (newLocale == Locale.ENGLISH) {
 222                                 if (notify) {
 223                                         notifyI18nables();
 224                                 }
 225                                 return;
 226                         }
 227                         inputStream = resourceClass.getResourceAsStream(resourceName + "_" + newLocale.getLanguage() + ".properties");
 228                         if (inputStream != null) {
 229                                 currentLanguage.load(inputStream);
 230                                 if (notify) {
 231                                         notifyI18nables();
 232                                 }
 233                         }
 234                 } catch (MissingResourceException mre1) {
 235                         currentLocale = Locale.ENGLISH;
 236                 } catch (IOException ioe1) {
 237                         currentLocale = Locale.ENGLISH;
 238                 } finally {
 239                         Closer.close(inputStream);
 240                 }
 241         }
 242
 243         /**
 244          * Returns the current locale.
 245          *
 246          * @return The current locale
 247          */
 248         public Locale getLocale() {
 249                 return currentLocale;
 250         }
 251
 252         /**
 253          * Finds all available locales.
 254          *
 255          * @return All available locales
 256          */
 257         public static List<Locale> findAvailableLanguages() {
 258                 List<Locale> availableLanguages = new ArrayList<Locale>();
 259                 availableLanguages.add(Locale.ENGLISH);
 260                 availableLanguages.add(Locale.GERMAN);
 261                 return availableLanguages;
 262         }
 263
 264         /**
 265          * Registers the given I18nable to be updated when the language is changed.
 266          *
 267          * @param i18nable
 268          *            The i18nable to register
 269          */
 270         public void registerI18nable(I18nable i18nable) {
 271                 i18nables.add(i18nable);
 272         }
 273
 274         /**
 275          * Deregisters the given I18nable to be updated when the language is
 276          * changed.
 277          *
 278          * @param i18nable
 279          *            The i18nable to register
 280          */
 281         public void deregisterI18nable(I18nable i18nable) {
 282                 i18nables.remove(i18nable);
 283         }
 284
 285         //
 286         // PRIVATE METHODS
 287         //
 288
 289         /**
 290          * Notifies all registered {@link I18nable}s that the language was changed.
 291          */
 292         private void notifyI18nables() {
 293                 for (I18nable i18nable : i18nables) {
 294                         i18nable.updateI18n(this);
 295                 }
 296         }
 297
 298 }