    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
    022 * acceptable header for most news readers.  To construct more
    023 * complicated headers you should refer to RFC 822.  When the
    024 * Java Mail API is finalized, you will be
    025 * able to use it to compose fully compliant Internet text messages.
    026 * <p>
    027 * The main purpose of the class is to faciliatate the article posting
    028 * process, by relieving the programmer from having to explicitly format
    029 * an article header.  For example:
    030 * <pre>
    031 * writer = client.postArticle();
    032 * if(writer == null) // failure
    033 *   return false;
    034 * header = new SimpleNNTPHeader("foobar@foo.com", "Just testing");
    035 * header.addNewsgroup("alt.test");
    036 * header.addHeaderField("Organization", "Foobar, Inc.");
    037 * writer.write(header.toString());
    038 * writer.write("This is just a test");
    039 * writer.close();
    040 * if(!client.completePendingCommand()) // failure
    041 *   return false;
    042 * </pre>
    043 *
    044 * @see NNTPClient
    045 ***/
    046
    047public class SimpleNNTPHeader
    048{
    049    private final String subject, from;
    050    private final StringBuilder newsgroups;
    051    private final StringBuilder headerFields;
    052    private int newsgroupCount;
    053
    054    /***
    055     * Creates a new SimpleNNTPHeader instance initialized with the given
    056     * from and subject header field values.
    057     * <p>
    058     * @param from  The value of the <code>From:</code> header field.  This
    059     *              should be the article poster's email address.
    060     * @param subject  The value of the <code>Subject:</code> header field.
    061     *              This should be the subject of the article.
    062     ***/
    063    public SimpleNNTPHeader(final String from, final String subject)
    064    {
    065        this.from = from;
    066        this.subject = subject;
    067        this.newsgroups = new StringBuilder();
    068        this.headerFields = new StringBuilder();
    069        this.newsgroupCount = 0;
    070    }
    071
    072    /***
    073     * Adds a newsgroup to the article <code>Newsgroups:</code> field.
    074     * <p>
    075     * @param newsgroup  The newsgroup to add to the article's newsgroup
    076     *                   distribution list.
    077     ***/
    078    public void addNewsgroup(final String newsgroup)
    079    {
    080        if (newsgroupCount++ > 0) {
    081            newsgroups.append(',');
    082        }
    083        newsgroups.append(newsgroup);
    084    }
    085
    086    /***
    087     * Adds an arbitrary header field with the given value to the article
    088     * header.  These headers will be written after the From, Newsgroups,
    089     * and Subject fields when the SimpleNNTPHeader is convertered to a string.
    090     * An example use would be:
    091     * <pre>
    092     * header.addHeaderField("Organization", "Foobar, Inc.");
    093     * </pre>
    094     * <p>
    095     * @param headerField  The header field to add, not including the colon.
    096     * @param value  The value of the added header field.
    097     ***/
    098    public void addHeaderField(final String headerField, final String value)
    099    {
    100        headerFields.append(headerField);
    101        headerFields.append(": ");
    102        headerFields.append(value);
    103        headerFields.append('\n');
    104    }
    105
    106
    107    /***
    108     * Returns the address used in the <code> From: </code> header field.
    109     * <p>
    110     * @return The from address.
    111     ***/
    112    public String getFromAddress()
    113    {
    114        return from;
    115    }
    116
    117    /***
    118     * Returns the subject used in the <code> Subject: </code> header field.
    119     * <p>
    120     * @return The subject.
    121     ***/
    122    public String getSubject()
    123    {
    124        return subject;
    125    }
    126
    127    /***
    128     * Returns the contents of the <code> Newsgroups: </code> header field.
    129     * <p>
    130     * @return The comma-separated list of newsgroups to which the article
    131     *         is being posted.
    132     ***/
    133    public String getNewsgroups()
    134    {
    135        return newsgroups.toString();
    136    }
    137
    138    /***
    139     * Converts the SimpleNNTPHeader to a properly formatted header in
    140     * the form of a String, including the blank line used to separate
    141     * the header from the article body.
    142     * <p>
    143     * @return The article header in the form of a String.
    144     ***/
    145    @Override
    146    public String toString()
    147    {
    148        final StringBuilder header = new StringBuilder();
    149
    150        header.append("From: ");
    151        header.append(from);
    152        header.append("\nNewsgroups: ");
    153        header.append(newsgroups.toString());
    154        header.append("\nSubject: ");
    155        header.append(subject);
    156        header.append('\n');
    157        if (headerFields.length() > 0) {
    158            header.append(headerFields.toString());
    159        }
    160        header.append('\n');
    161
    162        return header.toString();
    163    }
    164}