src/net/pterodactylus/jsite/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.jsite.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
  35 import javax.swing.KeyStroke;
  36
  37 import net.pterodactylus.util.io.Closer;
  38
  39 /**
  40  * Class that handles i18n.
  41  *
  42  * @author David ‘Bombe’ Roden &lt;bombe@freenetproject.org&gt;
  43  * @version $Id$
  44  */
  45 public class I18n {
  46
  47         /** The current locale. */
  48         private static Locale currentLocale;
  49
  50         /** The default language. */
  51         private static Properties defaultLanguage;
  52
  53         /** The current language. */
  54         private static Properties currentLanguage;
  55
  56         static {
  57                 defaultLanguage = new Properties();
  58                 InputStream inputStream = null;
  59                 try {
  60                         inputStream = I18n.class.getResourceAsStream("jSite.properties");
  61                         if (inputStream != null) {
  62                                 defaultLanguage.load(inputStream);
  63                         }
  64                 } catch (IOException e) {
  65                         /* something is fucked. */
  66                 }
  67                 setLocale(Locale.getDefault());
  68         }
  69
  70         /** List of I18nables that are notified when the language changes. */
  71         private static final List<I18nable> i18nables = new ArrayList<I18nable>();
  72
  73         /**
  74          * Returns the translated value for a key. The translated values may contain
  75          * placeholders that are replaced with the given parameters.
  76          *
  77          * @see MessageFormat
  78          * @param key
  79          *            The key to get
  80          * @param parameters
  81          *            The parameters in case the translated value contains
  82          *            placeholders
  83          * @return The translated message, or the key itself if no translation could
  84          *         be found
  85          */
  86         public static String get(String key, Object... parameters) {
  87                 String value = null;
  88                 value = currentLanguage.getProperty(key);
  89                 if (value == null) {
  90                         return key;
  91                 }
  92                 if ((parameters != null) && (parameters.length > 0)) {
  93                         return MessageFormat.format(value, parameters);
  94                 }
  95                 return value;
  96         }
  97
  98         /**
  99          * Returns the keycode from the value of the given key. You can specify the
 100          * constants in {@link KeyEvent} in the properties file, e.g. VK_S for the
 101          * keycode ‘s’ when used for mnemonics.
 102          *
 103          * @param key
 104          *            The key under which the keycode is stored
 105          * @return The keycode
 106          */
 107         public static int getKey(String key) {
 108                 String value = get(key);
 109                 if (value.startsWith("VK_")) {
 110                         try {
 111                                 Field field = KeyEvent.class.getField(value);
 112                                 return field.getInt(null);
 113                         } catch (SecurityException e) {
 114                                 /* ignore. */
 115                         } catch (NoSuchFieldException e) {
 116                                 /* ignore. */
 117                         } catch (IllegalArgumentException e) {
 118                                 /* ignore. */
 119                         } catch (IllegalAccessException e) {
 120                                 /* ignore. */
 121                         }
 122                 }
 123                 return value.toUpperCase().charAt(0);
 124         }
 125
 126         /**
 127          * Returns a key stroke for use with swing accelerators.
 128          *
 129          * @param key
 130          *            The key of the key stroke
 131          * @return The key stroke, or <code>null</code> if no key stroke could be
 132          *         created from the translated value
 133          */
 134         public static KeyStroke getKeyStroke(String key) {
 135                 String value = get(key);
 136                 if (value == null) {
 137                         return null;
 138                 }
 139                 StringTokenizer keyTokens = new StringTokenizer(value, "+- ");
 140                 int modifierMask = 0;
 141                 while (keyTokens.hasMoreTokens()) {
 142                         String keyToken = keyTokens.nextToken();
 143                         if ("ctrl".equalsIgnoreCase(keyToken)) {
 144                                 modifierMask |= InputEvent.CTRL_DOWN_MASK;
 145                         } else if ("alt".equalsIgnoreCase(keyToken)) {
 146                                 modifierMask |= InputEvent.ALT_DOWN_MASK;
 147                         } else if ("shift".equalsIgnoreCase(keyToken)) {
 148                                 modifierMask |= InputEvent.SHIFT_DOWN_MASK;
 149                         } else {
 150                                 if (keyToken.startsWith("VK_")) {
 151                                         try {
 152                                                 Field field = KeyEvent.class.getField(keyToken);
 153                                                 return KeyStroke.getKeyStroke(field.getInt(null), modifierMask);
 154                                         } catch (SecurityException e) {
 155                                                 /* ignore. */
 156                                         } catch (NoSuchFieldException e) {
 157                                                 /* ignore. */
 158                                         } catch (IllegalArgumentException e) {
 159                                                 /* ignore. */
 160                                         } catch (IllegalAccessException e) {
 161                                                 /* ignore. */
 162                                         }
 163                                 }
 164                                 return KeyStroke.getKeyStroke(keyToken.charAt(0), modifierMask);
 165                         }
 166                 }
 167                 return null;
 168         }
 169
 170         /**
 171          * Sets the current locale.
 172          *
 173          * @param newLocale
 174          *            The new locale to use
 175          */
 176         public static void setLocale(Locale newLocale) {
 177                 currentLocale = newLocale;
 178                 InputStream inputStream = null;
 179                 try {
 180                         currentLanguage = new Properties(defaultLanguage);
 181                         inputStream = I18n.class.getResourceAsStream("jSite_" + currentLocale.toString() + ".properties");
 182                         if (inputStream != null) {
 183                                 currentLanguage.load(inputStream);
 184                                 notifyI18nables();
 185                         }
 186                 } catch (MissingResourceException mre1) {
 187                         currentLocale = Locale.ENGLISH;
 188                 } catch (IOException ioe1) {
 189                         currentLocale = Locale.ENGLISH;
 190                 } finally {
 191                         Closer.close(inputStream);
 192                 }
 193         }
 194
 195         /**
 196          * Registers the given I18nable to be updated when the language is changed.
 197          *
 198          * @param i18nable
 199          *            The i18nable to register
 200          */
 201         public static void registerI18nable(I18nable i18nable) {
 202                 i18nables.add(i18nable);
 203         }
 204
 205         /**
 206          * Deregisters the given I18nable to be updated when the language is
 207          * changed.
 208          *
 209          * @param i18nable
 210          *            The i18nable to register
 211          */
 212         public static void deregisterI18nable(I18nable i18nable) {
 213                 i18nables.remove(i18nable);
 214         }
 215
 216         //
 217         // PRIVATE METHODS
 218         //
 219
 220         /**
 221          * Notifies all registered {@link I18nable}s that the language was changed.
 222          */
 223         private static void notifyI18nables() {
 224                 for (I18nable i18nable: i18nables) {
 225                         i18nable.updateI18n();
 226                 }
 227         }
 228
 229 }