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.smtp;
019
020/**
021 * SMTPCommand stores a set of constants for SMTP command codes. To interpret the meaning of the codes, familiarity with RFC 821 is assumed. The mnemonic
022 * constant names are transcriptions from the code descriptions of RFC 821. For those who think in terms of the actual SMTP commands, a set of constants such as
023 * {@link #HELO HELO } are provided where the constant name is the same as the SMTP command.
024 */
025
026public final class SMTPCommand {
027
028    public static final int HELO = 0;
029    public static final int MAIL = 1;
030    public static final int RCPT = 2;
031    public static final int DATA = 3;
032    public static final int SEND = 4;
033    public static final int SOML = 5;
034    public static final int SAML = 6;
035    public static final int RSET = 7;
036    public static final int VRFY = 8;
037    public static final int EXPN = 9;
038    public static final int HELP = 10;
039    public static final int NOOP = 11;
040    public static final int TURN = 12;
041    public static final int QUIT = 13;
042
043    /**
044     * The authorization command
045     *
046     * @since 3.0
047     */
048    public static final int AUTH = 14;
049
050    /**
051     * The extended hello command
052     *
053     * @since 3.0
054     */
055    public static final int EHLO = 15;
056
057    private static final int NEXT = EHLO + 1; // update as necessary when adding new entries
058
059    public static final int HELLO = HELO;
060    public static final int LOGIN = HELO;
061    public static final int MAIL_FROM = MAIL;
062    public static final int RECIPIENT = RCPT;
063    public static final int SEND_MESSAGE_DATA = DATA;
064    public static final int SEND_FROM = SEND;
065    public static final int SEND_OR_MAIL_FROM = SOML;
066    public static final int SEND_AND_MAIL_FROM = SAML;
067    public static final int RESET = RSET;
068    public static final int VERIFY = VRFY;
069    public static final int EXPAND = EXPN;
070    // public static final int HELP = HELP;
071    // public static final int NOOP = NOOP;
072    // public static final int TURN = TURN;
073    // public static final int QUIT = QUIT;
074    public static final int LOGOUT = QUIT;
075
076    private static final String[] commands = { "HELO", "MAIL FROM:", "RCPT TO:", "DATA", "SEND FROM:", "SOML FROM:", "SAML FROM:", "RSET", "VRFY", "EXPN",
077            "HELP", "NOOP", "TURN", "QUIT", "AUTH", "EHLO" };
078
079    static {
080        if (commands.length != NEXT) {
081            throw new RuntimeException("Error in array definition");
082        }
083    }
084
085    /**
086     * Retrieve the SMTP protocol command string corresponding to a specified command code.
087     * <p>
088     *
089     * @param command The command code.
090     * @return The SMTP protcol command string corresponding to a specified command code.
091     */
092    public static String getCommand(final int command) {
093        return commands[command];
094    }
095
096    // Cannot be instantiated
097    private SMTPCommand() {
098    }
099
100}