001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.http.header;
014
015import java.util.*;
016import java.util.function.*;
017
018import org.apache.juneau.http.annotation.*;
019
020/**
021 * Represents a parsed <l>Allow</l> HTTP response header.
022 *
023 * <p>
024 * Valid methods for a specified resource. To be used for a 405 Method not allowed.
025 *
026 * <h5 class='figure'>Example</h5>
027 * <p class='bcode w800'>
028 *    Allow: GET, HEAD
029 * </p>
030 *
031 * <h5 class='topic'>RFC2616 Specification</h5>
032 *
033 * The Allow entity-header field lists the set of methods supported by the resource identified by the Request-URI.
034 * The purpose of this field is strictly to inform the recipient of valid methods associated with the resource.
035 * An Allow header field MUST be present in a 405 (Method Not Allowed) response.
036 *
037 * <p class='bcode w800'>
038 *    Allow   = "Allow" ":" #Method
039 * </p>
040 *
041 * <p>
042 * Example of use:
043 * <p class='bcode w800'>
044 *    Allow: GET, HEAD, PUT
045 * </p>
046 *
047 * <p>
048 * This field cannot prevent a client from trying other methods.
049 * However, the indications given by the Allow header field value SHOULD be followed.
050 *
051 * <p>
052 * The actual set of allowed methods is defined by the origin server at the time of each request.
053 *
054 * <p>
055 * The Allow header field MAY be provided with a PUT request to recommend the methods to be supported by the new or
056 * modified resource.
057 *
058 * <p>
059 * The server is not required to support these methods and SHOULD include an Allow header in the response giving the
060 * actual supported methods.
061 *
062 * <p>
063 * A proxy MUST NOT modify the Allow header field even if it does not understand all the methods specified, since the
064 * user agent might
065 * have other means of communicating with the origin server.
066 *
067 * <ul class='seealso'>
068 *    <li class='extlink'>{@doc ExtRFC2616}
069 * </ul>
070 */
071@Header("Allow")
072public class Allow extends BasicCsvArrayHeader {
073
074   private static final long serialVersionUID = 1L;
075
076   /**
077    * Convenience creator.
078    *
079    * @param value
080    *    The header value.
081    *    <br>Can be any of the following:
082    *    <ul>
083    *       <li><c>String</c> - A comma-delimited string.
084    *       <li><c>String[]</c> - A pre-parsed value.
085    *       <li>Any other array type - Converted to <c>String[]</c>.
086    *       <li>Any {@link Collection} - Converted to <c>String[]</c>.
087    *       <li>Anything else - Converted to <c>String</c>.
088    *    </ul>
089    * @return The parsed <c>Allow</c> header, or <jk>null</jk> if the value was null.
090    */
091   public static Allow of(Object value) {
092      if (value == null)
093         return null;
094      return new Allow(value);
095   }
096
097   /**
098    * Convenience creator using supplier.
099    *
100    * <p>
101    * Header value is re-evaluated on each call to {@link #getValue()}.
102    *
103    * @param value
104    *    The header value supplier.
105    *    <br>Can be any of the following:
106    *    <ul>
107    *       <li><c>String</c> - A comma-delimited string.
108    *       <li><c>String[]</c> - A pre-parsed value.
109    *       <li>Any other array type - Converted to <c>String[]</c>.
110    *       <li>Any {@link Collection} - Converted to <c>String[]</c>.
111    *       <li>Anything else - Converted to <c>String</c>.
112    *    </ul>
113    * @return The parsed <c>Allow</c> header, or <jk>null</jk> if the value was null.
114    */
115   public static Allow of(Supplier<?> value) {
116      if (value == null)
117         return null;
118      return new Allow(value);
119   }
120
121   /**
122    * Constructor.
123    *
124    * @param value
125    *    The header value.
126    *    <br>Can be any of the following:
127    *    <ul>
128    *       <li><c>String</c> - A comma-delimited string.
129    *       <li><c>String[]</c> - A pre-parsed value.
130    *       <li>Any other array type - Converted to <c>String[]</c>.
131    *       <li>Any {@link Collection} - Converted to <c>String[]</c>.
132    *       <li>Anything else - Converted to <c>String</c>.
133    *       <li>A {@link Supplier} of anything on this list.
134    *    </ul>
135    */
136   public Allow(Object value) {
137      super("Allow", value);
138   }
139
140   /**
141    * Constructor
142    *
143    * @param value
144    *    The header value.
145    */
146   public Allow(String value) {
147      this((Object)value);
148   }
149}