001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.http.header;
018
019import java.util.function.*;
020
021import org.apache.juneau.*;
022import org.apache.juneau.commons.collections.*;
023import org.apache.juneau.http.annotation.*;
024
025/**
026 * Represents a parsed <l>Accept-Charset</l> HTTP request header.
027 *
028 * <p>
029 * Character sets that are acceptable.
030 *
031 * <h5 class='figure'>Example</h5>
032 * <p class='bcode'>
033 *    Accept-Charset: utf-8
034 * </p>
035 *
036 * <h5 class='topic'>RFC2616 Specification</h5>
037 *
038 * The Accept-Charset request-header field can be used to indicate what character sets are acceptable for the response.
039 *
040 * <p>
041 * This field allows clients capable of understanding more comprehensive or special- purpose character sets to signal
042 * that capability to a server which is capable of representing documents in those character sets.
043 * <p class='bcode'>
044 *    Accept-Charset = "Accept-Charset" ":"
045 *                     1#( ( charset | "*" )[ ";" "q" "=" qvalue ] )
046 * </p>
047 *
048 * <p>
049 * Character set values are described in section 3.4. Each charset MAY be given an associated quality value which
050 * represents the user's preference for that charset.
051 * The default value is q=1.
052 * An example is...
053 * <p class='bcode'>
054 *    Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
055 * </p>
056 *
057 * <p>
058 * The special value "*", if present in the Accept-Charset field, matches every character set (including ISO-8859-1)
059 * which is not mentioned elsewhere in the Accept-Charset field.
060 *
061 * <p>
062 * If no "*" is present in an Accept-Charset field, then all character sets not explicitly mentioned get a quality
063 * value of 0, except for ISO-8859-1, which gets a quality value of 1 if not explicitly mentioned.
064 *
065 * <p>
066 * If no Accept-Charset header is present, the default is that any character set is acceptable.
067 *
068 * <p>
069 * If an Accept-Charset header is present, and if the server cannot send a response which is acceptable according to
070 * the Accept-Charset header, then the server SHOULD send an error response with the 406 (not acceptable) status code,
071 * though the sending of an unacceptable response is also allowed.
072 *
073 * <h5 class='section'>See Also:</h5><ul>
074 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauRestCommonBasics">juneau-rest-common Basics</a>
075 *    <li class='extlink'><a class="doclink" href="https://www.w3.org/Protocols/rfc2616/rfc2616.html">Hypertext Transfer Protocol -- HTTP/1.1</a>
076 * </ul>
077 *
078 * @serial exclude
079 */
080@Header("Accept-Charset")
081public class AcceptCharset extends BasicStringRangesHeader {
082   private static final long serialVersionUID = 1L;
083   private static final String NAME = "Accept-Charset";
084
085   private static final Cache<String,AcceptCharset> CACHE = Cache.of(String.class, AcceptCharset.class).build();
086
087   /**
088    * Static creator.
089    *
090    * @param value
091    *    The header value.
092    *    <br>Must be parsable by {@link StringRanges#of(String)}.
093    *    <br>Can be <jk>null</jk>.
094    * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
095    */
096   public static AcceptCharset of(String value) {
097      return value == null ? null : CACHE.get(value, () -> new AcceptCharset(value));
098   }
099
100   /**
101    * Static creator.
102    *
103    * @param value
104    *    The header value.
105    *    <br>Can be <jk>null</jk>.
106    * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
107    */
108   public static AcceptCharset of(StringRanges value) {
109      return value == null ? null : new AcceptCharset(value);
110   }
111
112   /**
113    * Static creator with delayed value.
114    *
115    * <p>
116    * Header value is re-evaluated on each call to {@link #getValue()}.
117    *
118    * @param value
119    *    The supplier of the header value.
120    *    <br>Can be <jk>null</jk>.
121    * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
122    */
123   public static AcceptCharset of(Supplier<StringRanges> value) {
124      return value == null ? null : new AcceptCharset(value);
125   }
126
127   /**
128    * Constructor.
129    *
130    * @param value
131    *    The header value.
132    *    <br>Must be parsable by {@link StringRanges#of(String)}.
133    *    <br>Can be <jk>null</jk>.
134    */
135   public AcceptCharset(String value) {
136      super(NAME, value);
137   }
138
139   /**
140    * Constructor.
141    *
142    * @param value
143    *    The header value.
144    *    <br>Can be <jk>null</jk>.
145    */
146   public AcceptCharset(StringRanges value) {
147      super(NAME, value);
148   }
149
150   /**
151    * Constructor with delayed value.
152    *
153    * <p>
154    * Header value is re-evaluated on each call to {@link #getValue()}.
155    *
156    * @param value
157    *    The supplier of the header value.
158    *    <br>Can be <jk>null</jk>.
159    */
160   public AcceptCharset(Supplier<StringRanges> value) {
161      super(NAME, value);
162   }
163}