Java tutorial
/* * 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.smtp; /*** * 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 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 {@link #HELO HELO } are provided * where the constant name is the same as the SMTP command. * <p> * <p> ***/ public final class SMTPCommand { public static final int HELO = 0; public static final int MAIL = 1; public static final int RCPT = 2; public static final int DATA = 3; public static final int SEND = 4; public static final int SOML = 5; public static final int SAML = 6; public static final int RSET = 7; public static final int VRFY = 8; public static final int EXPN = 9; public static final int HELP = 10; public static final int NOOP = 11; public static final int TURN = 12; public static final int QUIT = 13; /** * The authorization command * @since 3.0 */ public static final int AUTH = 14; /** * The extended hello command * @since 3.0 */ public static final int EHLO = 15; private static final int _NEXT_ = EHLO + 1; // update as necessary when adding new entries public static final int HELLO = HELO; public static final int LOGIN = HELO; public static final int MAIL_FROM = MAIL; public static final int RECIPIENT = RCPT; public static final int SEND_MESSAGE_DATA = DATA; public static final int SEND_FROM = SEND; public static final int SEND_OR_MAIL_FROM = SOML; public static final int SEND_AND_MAIL_FROM = SAML; public static final int RESET = RSET; public static final int VERIFY = VRFY; public static final int EXPAND = EXPN; // public static final int HELP = HELP; // public static final int NOOP = NOOP; // public static final int TURN = TURN; // public static final int QUIT = QUIT; public static final int LOGOUT = QUIT; // Cannot be instantiated private SMTPCommand() { } private static final String[] _commands = { "HELO", "MAIL FROM:", "RCPT TO:", "DATA", "SEND FROM:", "SOML FROM:", "SAML FROM:", "RSET", "VRFY", "EXPN", "HELP", "NOOP", "TURN", "QUIT", "AUTH", "EHLO" }; static { if (_commands.length != _NEXT_) { throw new RuntimeException("Error in array definition"); } } /*** * Retrieve the SMTP protocol command string corresponding to a specified * command code. * <p> * @param command The command code. * @return The SMTP protcol command string corresponding to a specified * command code. ***/ public static final String getCommand(int command) { return _commands[command]; } }