1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.net.nntp;
19
20 /**
21 * This class is used to construct the bare minimum acceptable header for most newsreaders. To construct more complicated headers you should refer to RFC 822.
22 * When the Java Mail API is finalized, you will be able to use it to compose fully compliant Internet text messages.
23 * <p>
24 * The main purpose of the class is to faciliatate the article posting process, by relieving the programmer from having to explicitly format an article header.
25 * For example:
26 * </p>
27 *
28 * <pre>
29 * writer = client.postArticle();
30 * if (writer == null) // failure
31 * return false;
32 * header = new SimpleNNTPHeader("foobar@foo.com", "Just testing");
33 * header.addNewsgroup("alt.test");
34 * header.addHeaderField("Organization", "Foobar, Inc.");
35 * writer.write(header.toString());
36 * writer.write("This is just a test");
37 * writer.close();
38 * if (!client.completePendingCommand()) // failure
39 * return false;
40 * </pre>
41 *
42 * @see NNTPClient
43 */
44
45 public class SimpleNNTPHeader {
46 private final String subject, from;
47 private final StringBuilder newsgroups;
48 private final StringBuilder headerFields;
49 private int newsgroupCount;
50
51 /**
52 * Creates a new SimpleNNTPHeader instance initialized with the given from and subject header field values.
53 *
54 * @param from The value of the <code>From:</code> header field. This should be the article poster's email address.
55 * @param subject The value of the <code>Subject:</code> header field. This should be the subject of the article.
56 */
57 public SimpleNNTPHeader(final String from, final String subject) {
58 this.from = from;
59 this.subject = subject;
60 this.newsgroups = new StringBuilder();
61 this.headerFields = new StringBuilder();
62 this.newsgroupCount = 0;
63 }
64
65 /**
66 * Adds an arbitrary header field with the given value to the article header.
67 * These headers will be written after the {@code From}, Newsgroups, and Subject fields
68 * when the SimpleNNTPHeader is converted to a string. An example use would be:
69 *
70 * <pre>
71 * header.addHeaderField("Organization", "Foobar, Inc.");
72 * </pre>
73 *
74 * @param headerField The header field to add, not including the colon.
75 * @param value The value of the added header field.
76 */
77 public void addHeaderField(final String headerField, final String value) {
78 headerFields.append(headerField);
79 headerFields.append(": ");
80 headerFields.append(value);
81 headerFields.append('\n');
82 }
83
84 /**
85 * Adds a newsgroup to the article <code>Newsgroups:</code> field.
86 *
87 * @param newsgroup The newsgroup to add to the article's newsgroup distribution list.
88 */
89 public void addNewsgroup(final String newsgroup) {
90 if (newsgroupCount++ > 0) {
91 newsgroups.append(',');
92 }
93 newsgroups.append(newsgroup);
94 }
95
96 /**
97 * Returns the address used in the <code>From:</code> header field.
98 *
99 * @return The from address.
100 */
101 public String getFromAddress() {
102 return from;
103 }
104
105 /**
106 * Returns the contents of the <code>Newsgroups:</code> header field.
107 *
108 * @return The comma-separated list of newsgroups to which the article is being posted.
109 */
110 public String getNewsgroups() {
111 return newsgroups.toString();
112 }
113
114 /**
115 * Returns the subject used in the <code>Subject:</code> header field.
116 *
117 * @return The subject.
118 */
119 public String getSubject() {
120 return subject;
121 }
122
123 /**
124 * Converts the SimpleNNTPHeader to a properly formatted header in the form of a String, including the blank line used to separate the header from the
125 * article body.
126 *
127 * @return The article header in the form of a String.
128 */
129 @Override
130 public String toString() {
131 final StringBuilder header = new StringBuilder();
132
133 header.append("From: ");
134 header.append(from);
135 header.append("\nNewsgroups: ");
136 header.append(newsgroups.toString());
137 header.append("\nSubject: ");
138 header.append(subject);
139 header.append('\n');
140 if (headerFields.length() > 0) {
141 header.append(headerFields.toString());
142 }
143 header.append('\n');
144
145 return header.toString();
146 }
147 }