/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.net.nntp;

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.  When the
Java Mail API is finalized, you will be
able to use it to compose fully compliant Internet text messages.

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.  For example:
writer = client.postArticle();
if(writer == null) // failure
  return false;
header = new SimpleNNTPHeader("foobar@foo.com", "Just testing");
header.addNewsgroup("alt.test");
header.addHeaderField("Organization", "Foobar, Inc.");
writer.write(header.toString());
writer.write("This is just a test");
writer.close();
if(!client.completePendingCommand()) // failure
  return false;

See Also:
NNTPClient/***
 * 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.  When the
 * Java Mail API is finalized, you will be
 * able to use it to compose fully compliant Internet text messages.
 * <p>
 * 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.  For example:
 * <pre>
 * writer = client.postArticle();
 * if(writer == null) // failure
 *   return false;
 * header = new SimpleNNTPHeader("foobar@foo.com", "Just testing");
 * header.addNewsgroup("alt.test");
 * header.addHeaderField("Organization", "Foobar, Inc.");
 * writer.write(header.toString());
 * writer.write("This is just a test");
 * writer.close();
 * if(!client.completePendingCommand()) // failure
 *   return false;
 * </pre>
 *
 * @see NNTPClient
 ***/

public class SimpleNNTPHeader
{
    private final String __subject, __from;
    private final StringBuilder __newsgroups;
    private final StringBuilder __headerFields;
    private int __newsgroupCount;

    
Creates a new SimpleNNTPHeader instance initialized with the given
from and subject header field values.

Params:
from –  The value of the From: header field.  This
             should be the article poster's email address.
subject –  The value of the Subject: header field.
             This should be the subject of the article./***
     * Creates a new SimpleNNTPHeader instance initialized with the given
     * from and subject header field values.
     * <p>
     * @param from  The value of the <code>From:</code> header field.  This
     *              should be the article poster's email address.
     * @param subject  The value of the <code>Subject:</code> header field.
     *              This should be the subject of the article.
     ***/
    public SimpleNNTPHeader(String from, String subject)
    {
        __from = from;
        __subject = subject;
        __newsgroups = new StringBuilder();
        __headerFields = new StringBuilder();
        __newsgroupCount = 0;
    }

    
Adds a newsgroup to the article Newsgroups: field.

Params:
newsgroup –  The newsgroup to add to the article's newsgroup
                  distribution list./***
     * Adds a newsgroup to the article <code>Newsgroups:</code> field.
     * <p>
     * @param newsgroup  The newsgroup to add to the article's newsgroup
     *                   distribution list.
     ***/
    public void addNewsgroup(String newsgroup)
    {
        if (__newsgroupCount++ > 0) {
            __newsgroups.append(',');
        }
        __newsgroups.append(newsgroup);
    }

    
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 when the SimpleNNTPHeader is convertered to a string.
An example use would be:
header.addHeaderField("Organization", "Foobar, Inc.");


Params:
headerField –  The header field to add, not including the colon.
value –  The value of the added header field./***
     * 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 when the SimpleNNTPHeader is convertered to a string.
     * An example use would be:
     * <pre>
     * header.addHeaderField("Organization", "Foobar, Inc.");
     * </pre>
     * <p>
     * @param headerField  The header field to add, not including the colon.
     * @param value  The value of the added header field.
     ***/
    public void addHeaderField(String headerField, String value)
    {
        __headerFields.append(headerField);
        __headerFields.append(": ");
        __headerFields.append(value);
        __headerFields.append('\n');
    }


    
Returns the address used in the  From:  header field.

Returns:
The from address./***
     * Returns the address used in the <code> From: </code> header field.
     * <p>
     * @return The from address.
     ***/
    public String getFromAddress()
    {
        return __from;
    }

    
Returns the subject used in the  Subject:  header field.

Returns:
The subject./***
     * Returns the subject used in the <code> Subject: </code> header field.
     * <p>
     * @return The subject.
     ***/
    public String getSubject()
    {
        return __subject;
    }

    
Returns the contents of the  Newsgroups:  header field.

Returns:
The comma-separated list of newsgroups to which the article
        is being posted./***
     * Returns the contents of the <code> Newsgroups: </code> header field.
     * <p>
     * @return The comma-separated list of newsgroups to which the article
     *         is being posted.
     ***/
    public String getNewsgroups()
    {
        return __newsgroups.toString();
    }

    
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 article body.

Returns:
The article header in the form of a String./***
     * 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 article body.
     * <p>
     * @return The article header in the form of a String.
     ***/
    @Override
    public String toString()
    {
        StringBuilder header = new StringBuilder();

        header.append("From: ");
        header.append(__from);
        header.append("\nNewsgroups: ");
        header.append(__newsgroups.toString());
        header.append("\nSubject: ");
        header.append(__subject);
        header.append('\n');
        if (__headerFields.length() > 0) {
            header.append(__headerFields.toString());
        }
        header.append('\n');

        return header.toString();
    }
}