1   /*
    2    *  Licensed to the Apache Software Foundation (ASF) under one or more
    3    *  contributor license agreements.  See the NOTICE file distributed with
    4    *  this work for additional information regarding copyright ownership.
    5    *  The ASF licenses this file to You under the Apache License, Version 2.0
    6    *  (the "License"); you may not use this file except in compliance with
    7    *  the License.  You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
   10    *
   11    *  Unless required by applicable law or agreed to in writing, software
   12    *  distributed under the License is distributed on an "AS IS" BASIS,
   13    *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   14    *  See the License for the specific language governing permissions and
   15    *  limitations under the License.
   16    */
   17   
   18   package org.apache.tomcat.util.http;
   19   
   20   import java.util.Enumeration;
   21   import java.util.Hashtable;
   22   import java.util.Locale;
   23   import java.util.StringTokenizer;
   24   import java.util.Vector;
   25   
   26   /**
   27    * Util to process the "Accept-Language" header. Used by facade to implement
   28    * getLocale() and by StaticInterceptor.
   29    *
   30    * Not optimized - it's very slow.
   31    * 
   32    * @author James Duncan Davidson [duncan@eng.sun.com]
   33    * @author James Todd [gonzo@eng.sun.com]
   34    * @author Jason Hunter [jch@eng.sun.com]
   35    * @author Harish Prabandham
   36    * @author costin@eng.sun.com
   37    */
   38   public class AcceptLanguage {
   39   
   40       public static Locale getLocale(String acceptLanguage) {
   41           if( acceptLanguage == null ) return Locale.getDefault();
   42   
   43           Hashtable<String,Vector<String>> languages =
   44               new Hashtable<String,Vector<String>>();
   45           Vector<Double> quality = new Vector<Double>();
   46           processAcceptLanguage(acceptLanguage, languages, quality);
   47   
   48           if (languages.size() == 0) return Locale.getDefault();
   49   
   50           Vector<Locale> l = new Vector<Locale>();
   51           extractLocales( languages,quality, l);
   52   
   53           return (Locale)l.elementAt(0);
   54       }
   55   
   56       public static Enumeration getLocales(String acceptLanguage) {
   57               // Short circuit with an empty enumeration if null header
   58           if (acceptLanguage == null) {
   59               Vector<Locale> v = new Vector<Locale>();
   60               v.addElement(Locale.getDefault());
   61               return v.elements();
   62           }
   63           
   64           Hashtable<String,Vector<String>> languages =
   65               new Hashtable<String,Vector<String>>();
   66           Vector<Double> quality=new Vector<Double>();
   67               processAcceptLanguage(acceptLanguage, languages , quality);
   68   
   69           if (languages.size() == 0) {
   70               Vector<Locale> v = new Vector<Locale>();
   71               v.addElement(Locale.getDefault());
   72               return v.elements();
   73           }
   74               Vector<Locale> l = new Vector<Locale>();
   75               extractLocales( languages, quality , l);
   76               return l.elements();
   77       }
   78   
   79       private static void processAcceptLanguage( String acceptLanguage,
   80               Hashtable<String,Vector<String>> languages, Vector<Double> q)
   81       {
   82           StringTokenizer languageTokenizer =
   83               new StringTokenizer(acceptLanguage, ",");
   84   
   85           while (languageTokenizer.hasMoreTokens()) {
   86               String language = languageTokenizer.nextToken().trim();
   87               int qValueIndex = language.indexOf(';');
   88               int qIndex = language.indexOf('q');
   89               int equalIndex = language.indexOf('=');
   90               Double qValue = new Double(1);
   91   
   92               if (qValueIndex > -1 &&
   93                       qValueIndex < qIndex &&
   94                       qIndex < equalIndex) {
   95                       String qValueStr = language.substring(qValueIndex + 1);
   96                   language = language.substring(0, qValueIndex);
   97                   qValueStr = qValueStr.trim().toLowerCase();
   98                   qValueIndex = qValueStr.indexOf('=');
   99                   qValue = new Double(0);
  100                   if (qValueStr.startsWith("q") &&
  101                       qValueIndex > -1) {
  102                       qValueStr = qValueStr.substring(qValueIndex + 1);
  103                       try {
  104                           qValue = new Double(qValueStr.trim());
  105                       } catch (NumberFormatException nfe) {
  106                       }
  107                   }
  108               }
  109   
  110               // XXX
  111               // may need to handle "*" at some point in time
  112   
  113               if (! language.equals("*")) {
  114                   String key = qValue.toString();
  115                   Vector<String> v;
  116                   if (languages.containsKey(key)) {
  117                       v = languages.get(key) ;
  118                   } else {
  119                       v= new Vector<String>();
  120                       q.addElement(qValue);
  121                   }
  122                   v.addElement(language);
  123                   languages.put(key, v);
  124               }
  125           }
  126       }
  127   
  128       private static void extractLocales(Hashtable languages, Vector q,
  129               Vector<Locale> l)
  130       {
  131           // XXX We will need to order by q value Vector in the Future ?
  132           Enumeration e = q.elements();
  133           while (e.hasMoreElements()) {
  134               Vector v =
  135                   (Vector)languages.get(((Double)e.nextElement()).toString());
  136               Enumeration le = v.elements();
  137               while (le.hasMoreElements()) {
  138                       String language = (String)le.nextElement();
  139                           String country = "";
  140                           int countryIndex = language.indexOf("-");
  141                   if (countryIndex > -1) {
  142                       country = language.substring(countryIndex + 1).trim();
  143                       language = language.substring(0, countryIndex).trim();
  144                   }
  145                   l.addElement(new Locale(language, country));
  146               }
  147           }
  148       }
  149   
  150   
  151   }