mailserver.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;

import org.apache.log4j.Logger;
import org.jpxx.mail.Exception.InvalidServiceException;
import org.jpxx.mail.Domain.DomainHandler;

/**
 * <p>This is a core class for JMS. You can start, restart or stop it.</p>
 * <p>JMS has two services, which are SMTP and POP.</p>
 * 
 * @author Jun Li
 * @version $Revision: 0.0.3 $, $Date: 2008/10/25 $
 * @since JMS 0.0.1
 * 
 */
public class MailServer {

    /**
     * The software name
     */
    public final static String SOFTWARE_NAME = Constants.NAME;
    /**
     * The software Version
     */
    public final static String SOFTWARE_VERSION = Constants.VERSION;
    /**
     * Class factory
     */
    private Factory factory = Factory.getSingletonInstance();
    /**
     * Creates an instance of Logger and initializes it. 
     * It is to write log for <code>MailServer</code>.
     */
    private Logger log = factory.getLogger(this);
    /**
     * Singleton instance of MailServer
     */
    private static MailServer singletonInstance = null;
    /**
     * Server state. Started or stopped. 1 -started, 0 -stopped
     */
    private static int state = 0;

    /**
     * To make sure start one JMS. 
     * @since JMS 0.0.1
     * @return singleton instance of MailServer
     */
    public static MailServer getSingletonInstance() {
        if (singletonInstance == null) {
            singletonInstance = new MailServer();
        }
        return singletonInstance;
    }

    private MailServer() {
        /**
         * Start console server.
         */
        try {
            factory.getServer("Console").start();
        } catch (InvalidServiceException ise) {
            log.error(ise.toString());
        }
    }

    /**
     * <p>
     * Starts JMS. Before you start server, please adds a domain firstly
     * for server. JMS supports two or more domains.
     * </p>
     * 
     * <p>
     * This method that must not be executed by two threads simultaneously.
     * Note the American spelling, <b>synchronized</b>, that all Java terms use. 
     * A crucial block of code you don’t want two threads accessing 
     * simultaneously can be designed to allow only one thread through at a time.
     * </p>
     * @since JMS 0.0.1
     */
    public synchronized void startServer() {
        if (new DomainHandler().getDomains() == null) {
            log.error("Starts failed," +
                    " no domain for server. Please add a domain firstly.");
        } else if (state == 1) {
            log.error("Starts failed." +
                    " Server is already started.");
        } else {
            try {
                log.info("Start server");
                factory.getServer("Smtp").start();
                factory.getServer("Pop3").start();                
                state = 1;
            } catch (InvalidServiceException ise) {
                log.error(ise.toString());
            }
        }
    }

    /**
     * Restart JMS.
     * 
     * <p>
     * This method that must not be executed by two threads simultaneously.
     * </p>
     * @since JMS 0.0.1
     */
    public synchronized void restartServer() {
        if (state == 0) {
            log.error("Restart failed." +
                    " Can't restart here. Server not started.");
        } else {
            try {
                log.info("Restart server");
                factory.getServer("Smtp").restart();
                factory.getServer("Pop3").restart();
            } catch (InvalidServiceException ise) {
                log.error(ise.toString());
            }
        }
    }

    /**
     * Stop JMS.
     * 
     * <p>
     * This method that must not be executed by two threads simultaneously.
     * </p>
     * @since JMS 0.0.1
     */
    public synchronized void stopServer() {
        if (state == 0) {
            log.error("Stop failed." +
                    " Server not started at all.");
        } else {
            try {
                log.info("Stop server");
                factory.getServer("Smtp").stop();
                factory.getServer("Pop3").stop();
                state = 0;
            } catch (InvalidServiceException ise) {
                log.error(ise.toString());
            }
        }
    }

    /**
     * Returns server current state. 0 -stopped, 1 -started;
     * @return server current state. 0 -stopped, 1 -started;
     * @since JMS 0.0.3
     */
    public static int getState() {
        return state;
    }
}