helocommand.java

Java Mail Server JAVA编写的邮件服务器

/****************************************************************
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.     *
 *                                                              *
 * Copyright 2008 Jun Li(SiChuan University, the School of      *
 * Software Engineering). All rights reserved.                  *
 *                                                              *
 * Licensed to the JMS under one  or more contributor license   *
 * agreements.  See the LICENCE file  distributed with this     *
 * work for additional information regarding copyright          *
 * ownership.  The JMS licenses this file  you may not use this *
 * file except in compliance  with the License.                 *
 *                                                              *
 * 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.jpxx.mail.Smtp.Command;

import org.jpxx.mail.Exception.ArgumentException;
import org.jpxx.mail.Smtp.SmtpCommands;
import org.jpxx.mail.Service.*;

/**
 * Handle HELO command.
 * 
 * <p>The command is used to identify the SMTP client to the SMTP 
 * server. The argument field contains the fully-qualified domain name 
 * of the SMTP client if one is available. In situations in which the 
 * SMTP client system does not have a meaningful domain name (e.g., when 
 * its address is dynamically allocated and no reverse mapping record is 
 * available), the client SHOULD send an address literal ,  
 * optionally followed by information that will help to identify 
 * the client system. y The SMTP server identifies itself to the SMTP 
 * client in the connection greeting reply and in the response to this 
 * command. <p>
 * 
 * @author Jun Li
 * @version $Revision: 0.0.3 $, $Date: 2008/04/24 $
 * @since JMS 0.0.1
 * 
 */
public class HeloCommand implements CommandHandler, SmtpCommands, ServerState {

    /**
     * Handler method called upon receipt of a HELO command.
     * Responds with a greeting and informs the client whether
     * client authentication is required.
     * 
     * @see org.jpxx.mail.Service.CommandHandler#onCommand(Session session)
     * @param session The Session of Server and client
     */
    public void onCommand(Session session) {
        /**
         * Clear all buffers and reset the state exactly as if a RSET command 
         * had been issued.
         */
        session.clear();

        String argument = null;
        try {
            argument = session.getCommandLine().getArgument();
        } catch (ArgumentException ae) {
            argument = null;
        }

        if (argument == null) {
            session.writeResponse("501 Syntax error, Usage: HELO hostname");
        } else {
            session.writeResponse("250 OK");
            session.setLastAction(HELO);
        }

    }
}