    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 *      https://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 */
    025public final class SMTPCommand {
    026
    027    /** SMTP command {@value}. */
    028    public static final int HELO = 0;
    029
    030    /** SMTP command {@value}. */
    031    public static final int MAIL = 1;
    032
    033    /** SMTP command {@value}. */
    034    public static final int RCPT = 2;
    035
    036    /** SMTP command {@value}. */
    037    public static final int DATA = 3;
    038
    039    /** SMTP command {@value}. */
    040    public static final int SEND = 4;
    041
    042    /** SMTP command {@value}. */
    043    public static final int SOML = 5;
    044
    045    /** SMTP command {@value}. */
    046    public static final int SAML = 6;
    047
    048    /** SMTP command {@value}. */
    049    public static final int RSET = 7;
    050
    051    /** SMTP command {@value}. */
    052    public static final int VRFY = 8;
    053
    054    /** SMTP command {@value}. */
    055    public static final int EXPN = 9;
    056
    057    /** SMTP command {@value}. */
    058    public static final int HELP = 10;
    059
    060    /** SMTP command {@value}. */
    061    public static final int NOOP = 11;
    062
    063    /** SMTP command {@value}. */
    064    public static final int TURN = 12;
    065
    066    /** SMTP command {@value}. */
    067    public static final int QUIT = 13;
    068
    069    /**
    070     * The authorization command
    071     *
    072     * @since 3.0
    073     */
    074    public static final int AUTH = 14;
    075
    076    /**
    077     * The extended hello command
    078     *
    079     * @since 3.0
    080     */
    081    public static final int EHLO = 15;
    082
    083    private static final int NEXT = EHLO + 1; // update as necessary when adding new entries
    084
    085    /** Alias for {@value}. */
    086    public static final int HELLO = HELO;
    087
    088    /** Alias for {@value}. */
    089    public static final int LOGIN = HELO;
    090
    091    /** Alias for {@value}. */
    092    public static final int MAIL_FROM = MAIL;
    093
    094    /** Alias for {@value}. */
    095    public static final int RECIPIENT = RCPT;
    096
    097    /** Alias for {@value}. */
    098    public static final int SEND_MESSAGE_DATA = DATA;
    099
    100    /** Alias for {@value}. */
    101    public static final int SEND_FROM = SEND;
    102
    103    /** Alias for {@value}. */
    104    public static final int SEND_OR_MAIL_FROM = SOML;
    105
    106    /** Alias for {@value}. */
    107    public static final int SEND_AND_MAIL_FROM = SAML;
    108
    109    /** Alias for {@value}. */
    110    public static final int RESET = RSET;
    111
    112    /** Alias for {@value}. */
    113    public static final int VERIFY = VRFY;
    114
    115    /** Alias for {@value}. */
    116    public static final int EXPAND = EXPN;
    117
    118    /** Alias for {@value}. */
    119    public static final int LOGOUT = QUIT;
    120
    121    private static final String[] commands = { "HELO", "MAIL FROM:", "RCPT TO:", "DATA", "SEND FROM:", "SOML FROM:", "SAML FROM:", "RSET", "VRFY", "EXPN",
    122            "HELP", "NOOP", "TURN", "QUIT", "AUTH", "EHLO" };
    123
    124    static {
    125        if (commands.length != NEXT) {
    126            throw new IllegalStateException("Error in array definition");
    127        }
    128    }
    129
    130    /**
    131     * Gets the SMTP protocol command string corresponding to a specified command code.
    132     *
    133     * @param command The command code.
    134     * @return The SMTP protocol command string corresponding to a specified command code.
    135     */
    136    public static String getCommand(final int command) {
    137        return commands[command];
    138    }
    139
    140    /** Cannot be instantiated. */
    141    private SMTPCommand() {
    142    }
    143
    144}