content: /*
   * $Header$
   * $Revision$
   * $Date$
   *
   * ====================================================================
   *
   * Copyright 2000-2002 bob mcwhirter & James Strachan.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   * 
   *   * Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer.
   * 
   *   * Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution.
   * 
   *   * Neither the name of the Jaxen Project nor the names of its
   *     contributors may be used to endorse or promote products derived 
   *     from this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * ====================================================================
   * This software consists of voluntary contributions made by many 
   * individuals on behalf of the Jaxen Project and was originally 
   * created by bob mcwhirter <bob@werken.com> and 
   * James Strachan <jstrachan@apache.org>.  For more information on the 
   * Jaxen Project, please see <http://www.jaxen.org/>.
   * 
   * $Id$
   */
  
  package org.jaxen.function.ext;
  
  import java.util.List;
  import java.util.Locale;
  import java.util.StringTokenizer;
  
  import org.jaxen.Function;
  import org.jaxen.Navigator;
  import org.jaxen.function.StringFunction;
  
  /**
   * <p>An abstract base class for Locale-specific extension 
   * functions. This class provides convenience methods that
   * can be inherited, specifically to find a Locale from
   * an XPath function argument value.
   * </p>
   *
   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
   */
  public abstract class LocaleFunctionSupport implements Function
  {
  
      /** 
       * Attempts to convert the given function argument value 
       * into a Locale either via casting, extracting it from a List
       * or looking up the named Locale using reflection.
       *
       * @param value is either a Locale, a List containing a Locale
       *      or a String containing the name of a Locale
       *      as defined by the Locale static members.
       *
       * @return the Locale for the value or null if one could 
       *      not be deduced
       */
      protected Locale getLocale(Object value, Navigator navigator) 
      {
          if (value instanceof Locale)
          {
              return (Locale) value;
          }
          else if(value instanceof List)
          {
              List list = (List) value;
              if ( ! list.isEmpty() ) 
              {
                  return getLocale( list.get(0), navigator );
              }
          }
          else {
              String text = StringFunction.evaluate( value, navigator );
              if (text != null && text.length() > 0) 
              {
                  return findLocale( text );
              }
          }
          return null;
      }
      
      /** 
       * Tries to find a Locale instance by name using 
       * <a href="http://www.ietf.org/rfc/rfc3066.txt" target="_top">RFC 3066</a>
       * language tags such as 'en', 'en-US', 'en-US-Brooklyn'.
       *
       * @param localeText the RFC 3066 language tag
       * @return the locale for the given text or null if one could not
       *      be found 
       */
      protected Locale findLocale(String localeText) {
          StringTokenizer tokens = new StringTokenizer( localeText, "-" );
          if (tokens.hasMoreTokens())
          {
              String language = tokens.nextToken();
              if (! tokens.hasMoreTokens())
              {                
                  return findLocaleForLanguage(language);
              }
              else 
              {
                  String country = tokens.nextToken();
                  if (! tokens.hasMoreTokens())
                  {
                      return new Locale(language, country);
                  }
                  else 
                  {
                      String variant = tokens.nextToken();
                      return new Locale(language, country, variant);
                  }
              }
          }
          return null;
      }
      
      /** 
       * Finds the locale with the given language name with no country
       * or variant, such as Locale.ENGLISH or Locale.FRENCH
       *
       * @param language the language code to look for
       * @return the locale for the given language or null if one could not
       *      be found 
       */
      protected Locale findLocaleForLanguage(String language) {
          Locale[] locales = Locale.getAvailableLocales();
          for ( int i = 0, size = locales.length; i < size; i++ ) 
          {
              Locale locale = locales[i];
              if ( language.equals( locale.getLanguage() ) ) 
              {
                  String country = locale.getCountry();
                  if ( country == null || country.length() == 0 ) 
                  {
                      String variant = locale.getVariant();
                      if ( variant == null || variant.length() == 0 ) 
                      {
                          return locale;
                      }
                  }
              }
          }    
          return null;
      }
  }
  