| package org.apache.fulcrum.localization; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.Locale; |
| import java.util.NoSuchElementException; |
| import java.util.StringTokenizer; |
| |
| /** |
| * Parses the HTTP <code>Accept-Language</code> header as per section |
| * 14.4 of RFC 2068 (HTTP 1.1 header field definitions). |
| * |
| * @author <a href="mailto:dlr@collab.net">Daniel Rall</a> |
| * @version $Id$ |
| */ |
| public class LocaleTokenizer |
| implements Iterator<Object> |
| { |
| /** |
| * Separates elements of the <code>Accept-Language</code> HTTP |
| * header. |
| */ |
| private static final String LOCALE_SEPARATOR = ","; |
| |
| /** |
| * Separates locale from quality within elements. |
| */ |
| private static final char QUALITY_SEPARATOR = ';'; |
| |
| /** |
| * The default quality value for an <code>AcceptLanguage</code> |
| * object. |
| */ |
| protected static final Float DEFAULT_QUALITY = new Float(1.0f); |
| |
| /** |
| * The parsed locales. |
| */ |
| private ArrayList<AcceptLanguage> locales = new ArrayList<AcceptLanguage>(3); |
| |
| /** |
| * Parses the <code>Accept-Language</code> header. |
| * |
| * @param header The <code>Accept-Language</code> header |
| * (i.e. <code>en, es;q=0.8, zh-TW;q=0.1</code>). |
| */ |
| public LocaleTokenizer(String header) |
| { |
| StringTokenizer tok = new StringTokenizer(header, LOCALE_SEPARATOR); |
| while (tok.hasMoreTokens()) |
| { |
| AcceptLanguage acceptLang = new AcceptLanguage(); |
| String element = tok.nextToken().trim(); |
| int index; |
| |
| // Record and cut off any quality value that comes after a |
| // semi-colon. |
| if ( (index = element.indexOf(QUALITY_SEPARATOR)) != -1 ) |
| { |
| String q = element.substring(index); |
| element = element.substring(0, index); |
| if ( (index = q.indexOf('=')) != -1 ) |
| { |
| try |
| { |
| acceptLang.quality = |
| Float.valueOf(q.substring(index + 1)); |
| } |
| catch (NumberFormatException useDefault) |
| { |
| // ignore |
| } |
| } |
| } |
| |
| element = element.trim(); |
| |
| // Create a Locale from the language. A dash may separate the |
| // language from the country. |
| if ( (index = element.indexOf('-')) == -1 ) |
| { |
| // No dash means no country. |
| acceptLang.locale = new Locale(element, ""); |
| } |
| else |
| { |
| acceptLang.locale = new Locale(element.substring(0, index), |
| element.substring(index + 1)); |
| } |
| |
| locales.add(acceptLang); |
| } |
| |
| // Sort by quality in descending order. |
| Collections.sort(locales, Collections.reverseOrder()); |
| } |
| |
| /** |
| * @return Whether there are more locales. |
| */ |
| public boolean hasNext() |
| { |
| return !locales.isEmpty(); |
| } |
| |
| /** |
| * Creates a <code>Locale</code> from the next element of the |
| * <code>Accept-Language</code> header. |
| * |
| * @return The next highest-rated <code>Locale</code>. |
| * @throws NoSuchElementException No more locales. |
| */ |
| public Object next() |
| { |
| if (locales.isEmpty()) |
| { |
| throw new NoSuchElementException(); |
| } |
| return ((AcceptLanguage) locales.remove(0)).locale; |
| } |
| |
| /** |
| * Not implemented. |
| */ |
| public final void remove() |
| { |
| throw new UnsupportedOperationException(getClass().getName() + |
| " does not support remove()"); |
| } |
| |
| /** |
| * Struct representing an element of the HTTP |
| * <code>Accept-Language</code> header. |
| */ |
| protected static class AcceptLanguage implements Comparable<Object> |
| { |
| /** |
| * The language and country. |
| */ |
| Locale locale; |
| |
| /** |
| * The quality of our locale (as values approach |
| * <code>1.0</code>, they indicate increased user preference). |
| */ |
| Float quality = DEFAULT_QUALITY; |
| |
| @Override |
| public int compareTo(Object acceptLang) |
| { |
| if ( acceptLang == null ) |
| throw new NullPointerException("AcceptLanguage not found"); |
| |
| if ( acceptLang instanceof AcceptLanguage ) |
| { |
| Float q2 = ((AcceptLanguage) acceptLang).quality; |
| return quality.compareTo( q2 ); |
| } else { |
| throw new NullPointerException("The object to compare is not the correct type"); |
| } |
| |
| } |
| } |
| } |