HeaderValueFormatter.java revision 069490a5ca2fd1988d29daf45d892f47ad665115 
1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/message/HeaderValueFormatter.java $
3 * $Revision: 571954 $
4 * $Date: 2007-09-02 04:05:21 -0700 (Sun, 02 Sep 2007) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32package org.apache.http.message;
33
34
35import org.apache.http.HeaderElement;
36import org.apache.http.NameValuePair;
37import org.apache.http.util.CharArrayBuffer;
38
39
40
41/**
42 * Interface for formatting elements of a header value.
43 * This is the complement to {@link HeaderValueParser}.
44 * Instances of this interface are expected to be stateless and thread-safe.
45 *
46 * <p>
47 * All formatting methods accept an optional buffer argument.
48 * If a buffer is passed in, the formatted element will be appended
49 * and the modified buffer is returned. If no buffer is passed in,
50 * a new buffer will be created and filled with the formatted element.
51 * In both cases, the caller is allowed to modify the returned buffer.
52 * </p>
53 *
54 *
55 * <!-- empty lines above to avoid 'svn diff' context problems -->
56 * @version $Revision: 571954 $
57 *
58 * @since 4.0
59 */
60public interface HeaderValueFormatter {
61
62    /**
63     * Formats an array of header elements.
64     *
65     * @param buffer    the buffer to append to, or
66     *                  <code>null</code> to create a new buffer
67     * @param elems     the header elements to format
68     * @param quote     <code>true</code> to always format with quoted values,
69     *                  <code>false</code> to use quotes only when necessary
70     *
71     * @return  a buffer with the formatted header elements.
72     *          If the <code>buffer</code> argument was not <code>null</code>,
73     *          that buffer will be used and returned.
74     */
75    CharArrayBuffer formatElements(CharArrayBuffer buffer,
76                                   HeaderElement[] elems,
77                                   boolean quote)
78        ;
79
80
81    /**
82     * Formats one header element.
83     *
84     * @param buffer    the buffer to append to, or
85     *                  <code>null</code> to create a new buffer
86     * @param elem      the header element to format
87     * @param quote     <code>true</code> to always format with quoted values,
88     *                  <code>false</code> to use quotes only when necessary
89     *
90     * @return  a buffer with the formatted header element.
91     *          If the <code>buffer</code> argument was not <code>null</code>,
92     *          that buffer will be used and returned.
93     */
94    CharArrayBuffer formatHeaderElement(CharArrayBuffer buffer,
95                                        HeaderElement elem,
96                                        boolean quote)
97        ;
98
99
100
101    /**
102     * Formats the parameters of a header element.
103     * That's a list of name-value pairs, to be separated by semicolons.
104     * This method will <i>not</i> generate a leading semicolon.
105     *
106     * @param buffer    the buffer to append to, or
107     *                  <code>null</code> to create a new buffer
108     * @param nvps      the parameters (name-value pairs) to format
109     * @param quote     <code>true</code> to always format with quoted values,
110     *                  <code>false</code> to use quotes only when necessary
111     *
112     * @return  a buffer with the formatted parameters.
113     *          If the <code>buffer</code> argument was not <code>null</code>,
114     *          that buffer will be used and returned.
115     */
116    CharArrayBuffer formatParameters(CharArrayBuffer buffer,
117                                     NameValuePair[] nvps,
118                                     boolean quote)
119        ;
120
121
122    /**
123     * Formats one name-value pair, where the value is optional.
124     *
125     * @param buffer    the buffer to append to, or
126     *                  <code>null</code> to create a new buffer
127     * @param nvp       the name-value pair to format
128     * @param quote     <code>true</code> to always format with a quoted value,
129     *                  <code>false</code> to use quotes only when necessary
130     *
131     * @return  a buffer with the formatted name-value pair.
132     *          If the <code>buffer</code> argument was not <code>null</code>,
133     *          that buffer will be used and returned.
134     */
135    CharArrayBuffer formatNameValuePair(CharArrayBuffer buffer,
136                                        NameValuePair nvp,
137                                        boolean quote)
138        ;
139
140}
141
142