| // *************************************************************************************************************************** |
| // * 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. * |
| // *************************************************************************************************************************** |
| package org.apache.juneau.http; |
| |
| import static org.apache.juneau.http.Constants.*; |
| |
| import org.apache.juneau.http.annotation.*; |
| import org.apache.juneau.internal.*; |
| |
| /** |
| * Represents a parsed <l>Accept-Language</l> HTTP request header. |
| * |
| * <p> |
| * List of acceptable human languages for response. |
| * |
| * <h5 class='figure'>Example</h5> |
| * <p class='bcode w800'> |
| * Accept-Language: en-US |
| * </p> |
| * |
| * <h5 class='topic'>RFC2616 Specification</h5> |
| * |
| * The Accept-Language request-header field is similar to Accept, but restricts the set of natural languages that are |
| * preferred as a response to the request. |
| * Language tags are defined in section 3.10. |
| * |
| * <p class='bcode w800'> |
| * Accept-Language = "Accept-Language" ":" |
| * 1#( language-range [ ";" "q" "=" qvalue ] ) |
| * language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" ) |
| * </p> |
| * |
| * <p> |
| * Each language-range MAY be given an associated quality value which represents an estimate of the user's preference |
| * for the languages specified by that range. |
| * The quality value defaults to "q=1". |
| * For example... |
| * <p class='bcode w800'> |
| * Accept-Language: da, en-gb;q=0.8, en;q=0.7 |
| * </p> |
| * <p> |
| * ...would mean: "I prefer Danish, but will accept British English and other types of English." |
| * |
| * <p> |
| * A language-range matches a language-tag if it exactly equals the tag, or if it exactly equals a prefix of the tag |
| * such that the first tag character following the prefix is "-". |
| * |
| * <p> |
| * The special range "*", if present in the Accept-Language field, matches every tag not matched by any other range |
| * present in the Accept-Language field. |
| * |
| * <p> |
| * Note: This use of a prefix matching rule does not imply that language tags are assigned to languages in such a way |
| * that it is always true that if a user understands a language with a certain |
| * tag, then this user will also understand all languages with tags for which this tag is a prefix. |
| * The prefix rule simply allows the use of prefix tags if this is the case. |
| * |
| * <p> |
| * The language quality factor assigned to a language-tag by the Accept-Language field is the quality value of the |
| * longest language- range in the field that matches the language-tag. |
| * |
| * <p> |
| * If no language- range in the field matches the tag, the language quality factor assigned is 0. |
| * |
| * <p> |
| * If no Accept-Language header is present in the request, the server SHOULD assume that all languages are equally |
| * acceptable. |
| * |
| * <p> |
| * If an Accept-Language header is present, then all languages which are assigned a quality factor greater than 0 are |
| * acceptable. |
| * |
| * <p> |
| * It might be contrary to the privacy expectations of the user to send an Accept-Language header with the complete |
| * linguistic preferences of the user in every request. |
| * For a discussion of this issue, see section 15.1.4. |
| * |
| * <p> |
| * As intelligibility is highly dependent on the individual user, it is recommended that client applications make the |
| * choice of linguistic preference available to the user. |
| * If the choice is not made available, then the Accept-Language header field MUST NOT be given in the request. |
| * |
| * <p> |
| * Note: When making the choice of linguistic preference available to the user, we remind implementors of the fact that |
| * users are not familiar with the details of language matching as described above, and should provide appropriate |
| * guidance. |
| * As an example, users might assume that on selecting "en-gb", they will be served any kind of English document if |
| * British English is not available. |
| * A user agent might suggest in such a case to add "en" to get the best matching behavior. |
| * |
| * <ul class='seealso'> |
| * <li class='extlink'>{@doc RFC2616} |
| * </ul> |
| */ |
| @Header("Accept-Language") |
| public final class AcceptLanguage extends HeaderRangeArray { |
| |
| private static final Cache<String,AcceptLanguage> cache = new Cache<>(NOCACHE, CACHE_MAX_SIZE); |
| |
| /** |
| * Returns a parsed <c>Accept-Language</c> header. |
| * |
| * @param value The <c>Accept-Language</c> header string. |
| * @return The parsed <c>Accept-Language</c> header, or <jk>null</jk> if the string was null. |
| */ |
| public static AcceptLanguage forString(String value) { |
| if (value == null) |
| return null; |
| AcceptLanguage a = cache.get(value); |
| if (a == null) |
| a = cache.put(value, new AcceptLanguage(value)); |
| return a; |
| } |
| |
| private AcceptLanguage(String raw) { |
| super(raw); |
| } |
| } |