Initial revision

From-SVN: r102074

libjava/classpath/gnu/java/locale/LocaleHelper.java

@@ -0,0 +1,158 @@
+/* LocaleHelper.java -- helper routines for localization
+   Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package gnu.java.locale;
+
+import java.util.Locale;
+import java.util.MissingResourceException;
+import java.util.ResourceBundle;
+
+/**
+ * This class provides common helper methods
+ * for handling localized data.
+ *
+ * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
+ *
+ * @see java.util.Locale
+ * @see java.util.ResourceBundle
+ */
+public class LocaleHelper
+{
+  /**
+   * This method is used by the localized name lookup methods to retrieve
+   * the localized name of a particular piece of locale data.    
+   * If the display name can not be localized to the supplied
+   * locale, it will fall back on other output in the following order:
+   *
+   * <ul>
+   * <li>the localized name in the default locale</li>
+   * <li>the localized name in English (optional)</li>
+   * <li>the localized name in the root locale bundle (optional)</li>
+   * <li>the localized input string</li>
+   * </ul>
+   * <p>
+   * If the supplied key is merely the empty string, then the empty string is
+   * returned.
+   * </p>
+   *
+   * @param inLocale the locale to use for formatting the display string.
+   * @param key the locale data used as a key to the localized lookup tables.
+   * @param name the name of the hashtable containing the localized data.
+   * @param checkEnglish true if the method should fall back on data
+   *        from the English locale.
+   * @param checkRoot true if the method should fall back on data from the
+   *        unlocalized root locale.
+   * @return a <code>String</code>, hopefully containing the localized
+   *         variant of the input data.
+   * @throws NullPointerException if <code>inLocale</code> is null. 
+   */
+  public static String getLocalizedString(Locale inLocale, String key,
+					  String name, boolean checkEnglish,
+					  boolean checkRoot)
+  {
+    String localizedString;
+    String property;
+
+    if (key.equals(""))
+      return "";
+    property = name + "." + key;
+    /* Localize to inLocale */
+    try
+      {
+        localizedString =
+	  ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
+				   inLocale).getString(property);
+      }
+    catch (MissingResourceException exception)
+      {
+	localizedString = null;
+      }
+    /* Localize to default locale */
+    if (localizedString == null)
+      {
+	try 
+	  {
+	    ResourceBundle bundle;
+	    
+	    bundle = 
+	      ResourceBundle.getBundle("gnu.java.locale.LocaleInformation");
+	    localizedString = bundle.getString(property);
+	  }
+	catch (MissingResourceException exception)
+	  {
+	    localizedString = null;
+	  }
+      }
+    /* Localize to English */
+    if (localizedString == null && checkEnglish)
+      {
+	try
+	  {
+	    localizedString = 
+	      ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
+				       Locale.ENGLISH).getString(property);
+	  }
+	catch (MissingResourceException exception)
+	  {
+	    localizedString = null;
+	  }
+      }
+    /* Return unlocalized version */
+    if (localizedString == null && checkRoot)
+      {
+	try
+	  {
+	    localizedString = 
+	      ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
+				       new Locale("","","")
+				       ).getString(property);
+	  }
+	catch (MissingResourceException exception)
+	  {
+	    localizedString = null;
+	  }
+      }
+    /* Return original input string */
+    if (localizedString == null)
+      {
+	localizedString = key;
+      }
+    return localizedString;
+  }
+}
+