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1 package org.apache.turbine.services.localization; 2 3 /* ==================================================================== 4 * The Apache Software License, Version 1.1 5 * 6 * Copyright (c) 2001 The Apache Software Foundation. All rights 7 * reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. The end-user documentation included with the redistribution, 22 * if any, must include the following acknowledgment: 23 * "This product includes software developed by the 24 * Apache Software Foundation (http://www.apache.org/)." 25 * Alternately, this acknowledgment may appear in the software itself, 26 * if and wherever such third-party acknowledgments normally appear. 27 * 28 * 4. The names "Apache" and "Apache Software Foundation" and 29 * "Apache Turbine" must not be used to endorse or promote products 30 * derived from this software without prior written permission. For 31 * written permission, please contact apache@apache.org. 32 * 33 * 5. Products derived from this software may not be called "Apache", 34 * "Apache Turbine", nor may "Apache" appear in their name, without 35 * prior written permission of the Apache Software Foundation. 36 * 37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 48 * SUCH DAMAGE. 49 * ==================================================================== 50 * 51 * This software consists of voluntary contributions made by many 52 * individuals on behalf of the Apache Software Foundation. For more 53 * information on the Apache Software Foundation, please see 54 * <http://www.apache.org/>;. 55 */ 56 57 import java.util.ArrayList; 58 import java.util.Collections; 59 import java.util.Iterator; 60 import java.util.Locale; 61 import java.util.NoSuchElementException; 62 import java.util.StringTokenizer; 63 64 /*** 65 * Parses the HTTP <code>Accept-Language</code> header as per section 66 * 14.4 of RFC 2068 (HTTP 1.1 header field definitions). 67 * 68 * @author <a href="mailto:dlr@collab.net">Daniel Rall</a> 69 * @version $Id: LocaleTokenizer.java,v 1.1 2001/10/13 23:15:24 dlr Exp $ 70 */ 71 public class LocaleTokenizer 72 implements Iterator 73 { 74 /*** 75 * Separates elements of the <code>Accept-Language</code> HTTP 76 * header. 77 */ 78 private static final String LOCALE_SEPARATOR = ","; 79 80 /*** 81 * Separates locale from quality within elements. 82 */ 83 private static final char QUALITY_SEPARATOR = ';'; 84 85 /*** 86 * The default quality value for an <code>AcceptLanguage</code> 87 * object. 88 */ 89 private static final Float DEFAULT_QUALITY = new Float(1.0f); 90 91 /*** 92 * The parsed locales. 93 */ 94 private ArrayList locales = new ArrayList(3); 95 96 /*** 97 * Parses the <code>Accept-Language</code> header. 98 * 99 * @param header The <code>Accept-Language</code> header 100 * (i.e. <code>en, es;q=0.8, zh-TW;q=0.1</code>). 101 */ 102 public LocaleTokenizer(String header) 103 { 104 StringTokenizer tok = new StringTokenizer(header, LOCALE_SEPARATOR); 105 while (tok.hasMoreTokens()) 106 { 107 AcceptLanguage acceptLang = new AcceptLanguage(); 108 String element = tok.nextToken().trim(); 109 int index; 110 111 // Record and cut off any quality value that comes after a 112 // semi-colon. 113 if ( (index = element.indexOf(QUALITY_SEPARATOR)) != -1 ) 114 { 115 String q = element.substring(index); 116 element = element.substring(0, index); 117 if ( (index = q.indexOf('=')) != -1 ) 118 { 119 try 120 { 121 acceptLang.quality = 122 Float.valueOf(q.substring(index + 1)); 123 } 124 catch (NumberFormatException useDefault) 125 { 126 } 127 } 128 } 129 130 element = element.trim(); 131 132 // Create a Locale from the language. A dash may separate the 133 // language from the country. 134 if ( (index = element.indexOf('-')) == -1 ) 135 { 136 // No dash means no country. 137 acceptLang.locale = new Locale(element, ""); 138 } 139 else 140 { 141 acceptLang.locale = new Locale(element.substring(0, index), 142 element.substring(index + 1)); 143 } 144 145 locales.add(acceptLang); 146 } 147 148 // Sort by quality in descending order. 149 Collections.sort(locales, Collections.reverseOrder()); 150 } 151 152 /*** 153 * @return Whether there are more locales. 154 */ 155 public boolean hasNext() 156 { 157 return !locales.isEmpty(); 158 } 159 160 /*** 161 * Creates a <code>Locale</code> from the next element of the 162 * <code>Accept-Language</code> header. 163 * 164 * @return The next highest-rated <code>Locale</code>. 165 * @throws NoSuchElementException No more locales. 166 */ 167 public Object next() 168 { 169 if (locales.isEmpty()) 170 { 171 throw new NoSuchElementException(); 172 } 173 return ((AcceptLanguage) locales.remove(0)).locale; 174 } 175 176 /*** 177 * Not implemented. 178 */ 179 public final void remove() 180 { 181 throw new UnsupportedOperationException(getClass().getName() + 182 " does not support remove()"); 183 } 184 185 /*** 186 * Struct representing an element of the HTTP 187 * <code>Accept-Language</code> header. 188 */ 189 private class AcceptLanguage implements Comparable 190 { 191 /*** 192 * The language and country. 193 */ 194 Locale locale; 195 196 /*** 197 * The quality of our locale (as values approach 198 * <code>1.0</code>, they indicate increased user preference). 199 */ 200 Float quality = DEFAULT_QUALITY; 201 202 public final int compareTo(Object acceptLang) 203 { 204 return quality.compareTo( ((AcceptLanguage) acceptLang).quality ); 205 } 206 } 207 }

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