    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 */
    017
    018package org.apache.commons.net.nntp;
    019
    020/**
    021 * This class is used to construct the bare minimum acceptable header for most news readers. To construct more complicated headers you should refer to RFC 822.
    022 * When the Java Mail API is finalized, you will be able to use it to compose fully compliant Internet text messages.
    023 * <p>
    024 * 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.
    025 * For example:
    026 *
    027 * <pre>
    028 * writer = client.postArticle();
    029 * if (writer == null) // failure
    030 *     return false;
    031 * header = new SimpleNNTPHeader("foobar@foo.com", "Just testing");
    032 * header.addNewsgroup("alt.test");
    033 * header.addHeaderField("Organization", "Foobar, Inc.");
    034 * writer.write(header.toString());
    035 * writer.write("This is just a test");
    036 * writer.close();
    037 * if (!client.completePendingCommand()) // failure
    038 *     return false;
    039 * </pre>
    040 *
    041 * @see NNTPClient
    042 */
    043
    044public class SimpleNNTPHeader {
    045    private final String subject, from;
    046    private final StringBuilder newsgroups;
    047    private final StringBuilder headerFields;
    048    private int newsgroupCount;
    049
    050    /**
    051     * Creates a new SimpleNNTPHeader instance initialized with the given from and subject header field values.
    052     * <p>
    053     *
    054     * @param from    The value of the <code>From:</code> header field. This should be the article poster's email address.
    055     * @param subject The value of the <code>Subject:</code> header field. This should be the subject of the article.
    056     */
    057    public SimpleNNTPHeader(final String from, final String subject) {
    058        this.from = from;
    059        this.subject = subject;
    060        this.newsgroups = new StringBuilder();
    061        this.headerFields = new StringBuilder();
    062        this.newsgroupCount = 0;
    063    }
    064
    065    /**
    066     * Adds an arbitrary header field with the given value to the article header. These headers will be written after the From, Newsgroups, and Subject fields
    067     * when the SimpleNNTPHeader is convertered to a string. An example use would be:
    068     *
    069     * <pre>
    070     * header.addHeaderField("Organization", "Foobar, Inc.");
    071     * </pre>
    072     * <p>
    073     *
    074     * @param headerField The header field to add, not including the colon.
    075     * @param value       The value of the added header field.
    076     */
    077    public void addHeaderField(final String headerField, final String value) {
    078        headerFields.append(headerField);
    079        headerFields.append(": ");
    080        headerFields.append(value);
    081        headerFields.append('\n');
    082    }
    083
    084    /**
    085     * Adds a newsgroup to the article <code>Newsgroups:</code> field.
    086     * <p>
    087     *
    088     * @param newsgroup The newsgroup to add to the article's newsgroup distribution list.
    089     */
    090    public void addNewsgroup(final String newsgroup) {
    091        if (newsgroupCount++ > 0) {
    092            newsgroups.append(',');
    093        }
    094        newsgroups.append(newsgroup);
    095    }
    096
    097    /**
    098     * Returns the address used in the <code> From: </code> header field.
    099     * <p>
    100     *
    101     * @return The from address.
    102     */
    103    public String getFromAddress() {
    104        return from;
    105    }
    106
    107    /**
    108     * Returns the contents of the <code> Newsgroups: </code> header field.
    109     * <p>
    110     *
    111     * @return The comma-separated list of newsgroups to which the article is being posted.
    112     */
    113    public String getNewsgroups() {
    114        return newsgroups.toString();
    115    }
    116
    117    /**
    118     * Returns the subject used in the <code> Subject: </code> header field.
    119     * <p>
    120     *
    121     * @return The subject.
    122     */
    123    public String getSubject() {
    124        return subject;
    125    }
    126
    127    /**
    128     * 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
    129     * article body.
    130     * <p>
    131     *
    132     * @return The article header in the form of a String.
    133     */
    134    @Override
    135    public String toString() {
    136        final StringBuilder header = new StringBuilder();
    137
    138        header.append("From: ");
    139        header.append(from);
    140        header.append("\nNewsgroups: ");
    141        header.append(newsgroups.toString());
    142        header.append("\nSubject: ");
    143        header.append(subject);
    144        header.append('\n');
    145        if (headerFields.length() > 0) {
    146            header.append(headerFields.toString());
    147        }
    148        header.append('\n');
    149
    150        return header.toString();
    151    }
    152}