linearprocessor.java

java 开发的邮件服务器平台。支持以下协议。 协议可以修改为自己的专门标识

/***********************************************************************
 * Copyright (c) 2000-2004 The Apache Software Foundation.             *
 * All rights reserved.                                                *
 * ------------------------------------------------------------------- *
 * Licensed 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.                      *
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package org.apache.james.transport;

import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.logger.Logger;
import org.apache.james.core.MailImpl;
import org.apache.james.core.MailetConfigImpl;
import org.apache.james.services.SpoolRepository;
import org.apache.mailet.*;

import javax.mail.MessagingException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Random;
import java.util.Iterator;
import java.util.Locale;

/**
 * Implements a processor for mails, directing the mail down
 * the chain of matchers/mailets.
 *
 *  SAMPLE CONFIGURATION
 *  <processor name="try" onerror="return,log">
 *      <mailet match="RecipientIsLocal" class="LocalDelivery">
 *      </mailet>
 *      <mailet match="All" class="RemoteDelivery">
 *          <delayTime>21600000</delayTime>
 *          <maxRetries>5</maxRetries>
 *      </mailet>
 *  </processor>
 *
 * Note that the 'onerror' attribute is not yet supported.
 *
 * As of James v2.2.0a5, 'onerror' functionality is implemented, but
 * it is implemented on the <mailet> tag.  The specification is:
 *
 *   <mailet match="..." class="..."
 *       [onMatchException="{noMatch|matchAll|error|<aProcessorName>}"] 
 *       [onMailetException="{ignore|error|<aProcessorName>}"]>
 *
 * noMatch:   no addresses are considered to match
 * matchAll:  all addresses are considered to match
 * error:     as before, send the message to the ERROR processor
 *
 * Otherwise, a processor name can be specified, and the message will
 * be sent there.
 *
 * <P>CVS $Id: LinearProcessor.java,v 1.10.4.7 2004/04/14 06:41:56 noel Exp $</P>
 * @version 2.2.0
 */
public class LinearProcessor 
    extends AbstractLogEnabled
    implements Initializable, Disposable {

    private static final Random random = new Random();  // Used to generate new mail names

    /**
     *  The name of the matcher used to terminate the matcher chain.  The
     *  end of the matcher/mailet chain must be a matcher that matches
     *  all mails and a mailet that sets every mail to GHOST status.
     *  This is necessary to ensure that mails are removed from the spool
     *  in an orderly fashion.
     */
    private static final String TERMINATING_MATCHER_NAME = "Terminating%Matcher%Name";

    /**
     *  The name of the mailet used to terminate the mailet chain.  The
     *  end of the matcher/mailet chain must be a matcher that matches
     *  all mails and a mailet that sets every mail to GHOST status.
     *  This is necessary to ensure that mails are removed from the spool
     *  in an orderly fashion.
     */
    private static final String TERMINATING_MAILET_NAME = "Terminating%Mailet%Name";

    private List mailets;  // The list of mailets for this processor
    private List matchers; // The list of matchers for this processor
    private volatile boolean listsClosed;  // Whether the matcher/mailet lists have been closed.
    private SpoolRepository spool;  // The spool on which this processor is acting

    /**
     * Set the spool to be used by this LinearProcessor.
     *
     * @param spool the spool to be used by this processor
     *
     * @throws IllegalArgumentException when the spool passed in is null
     */
    public void setSpool(SpoolRepository spool) {
        if (spool == null) {
            throw new IllegalArgumentException("The spool cannot be null");
        }
        this.spool = spool;
    }

    /**
     * @see org.apache.avalon.framework.activity.Initializable#initialize()
     */
    public void initialize() {
        matchers = new ArrayList();
        mailets = new ArrayList();
    }

    /**
     * <p>The dispose operation is called at the end of a components lifecycle.
     * Instances of this class use this method to release and destroy any
     * resources that they own.</p>
     *
     * <p>This implementation disposes of all the mailet instances added to the
     * processor</p>
     *
     * @throws Exception if an error is encountered during shutdown
     */
    public void dispose() {
        Iterator it = mailets.iterator();
        boolean debugEnabled = getLogger().isDebugEnabled();
        while (it.hasNext()) {
            Mailet mailet = (Mailet)it.next();
            if (debugEnabled) {
                getLogger().debug("Shutdown mailet " + mailet.getMailetInfo());
            }
            mailet.destroy();
        }
    }

    /**
     * <p>Adds a new <code>Matcher</code> / <code>Mailet</code> pair
     * to the processor.  Checks to ensure that the matcher and
     * mailet passed in are not null.  Synchronized to ensure that
     * the matchers and mailets are kept in sync.</p>
     *
     * <p>It is an essential part of the contract of the LinearProcessor
     * that a particular matcher/mailet combination be used to
     * terminate the processor chain.  This is done by calling the  
     * closeProcessorList method.</p>
     *
     * <p>Once the closeProcessorList has been called any subsequent
     * call to the add method will result in an IllegalStateException.</p>
     *
     * <p>This method is synchronized to protect against corruption of
     * matcher/mailets lists</p>
     *
     * @param matcher the new matcher being added
     * @param mailet the new mailet being added
     *
     * @throws IllegalArgumentException when the matcher or mailet passed in is null
     * @throws IllegalStateException when this method is called after the processor lists have been closed
     */
    public synchronized void add(Matcher matcher, Mailet mailet) {
        if (matcher == null) {
            throw new IllegalArgumentException("Null valued matcher passed to LinearProcessor.");
        }
        if (mailet == null) {
            throw new IllegalArgumentException("Null valued mailet passed to LinearProcessor.");
        }
        if (listsClosed) {
            throw new IllegalStateException("Attempt to add matcher/mailet after lists have been closed");
        }
        matchers.add(matcher);
        mailets.add(mailet);
    }

    /**
     * <p>Closes the processor matcher/mailet list.</p>
     *
     * <p>This method is synchronized to protect against corruption of
     * matcher/mailets lists</p>
     *
     * @throws IllegalStateException when this method is called after the processor lists have been closed
     */
    public synchronized void closeProcessorLists() {
        if (listsClosed) {
            throw new IllegalStateException("Processor's matcher/mailet lists have already been closed.");
        }
        Matcher terminatingMatcher =
            new GenericMatcher() {
                public Collection match(Mail mail) {
                    return mail.getRecipients();
                }
            
                public String getMatcherInfo() {
                    return TERMINATING_MATCHER_NAME;
                }
            };
        Mailet terminatingMailet = 
            new GenericMailet() {
                public void service(Mail mail) {
                    if (!(Mail.ERROR.equals(mail.getState()))) {
                        // Don't complain if we fall off the end of the
                        // error processor.  That is currently the
                        // normal situation for James, and the message
                        // will show up in the error store.
                        StringBuffer warnBuffer = new StringBuffer(256)
                                              .append("Message ")
                                              .append(((MailImpl)mail).getName())
                                              .append(" reached the end of this processor, and is automatically deleted.  This may indicate a configuration error.");
                        LinearProcessor.this.getLogger().warn(warnBuffer.toString());
                    }
                    mail.setState(Mail.GHOST);
                }
            
                public String getMailetInfo() {
                    return getMailetName();
                }
            
                public String getMailetName() {
                    return TERMINATING_MAILET_NAME;
                }
            };
        add(terminatingMatcher, terminatingMailet);
        listsClosed = true;
    }

    /**
     * <p>Processes a single mail message through the chain of matchers and mailets.</p>
     *
     * <p>Calls to this method before setSpool has been called with a non-null argument
     * will result in an <code>IllegalStateException</code>.</p>
     *
     * <p>If the matcher/mailet lists have not been closed by a call to the closeProcessorLists
     * method then a call to this method will result in an <code>IllegalStateException</code>.
     * The end of the matcher/mailet chain must be a matcher that matches all mails and 
     * a mailet that sets every mail to GHOST status.  This is necessary to ensure that 
     * mails are removed from the spool in an orderly fashion.  The closeProcessorLists method
     * ensures this.</p>
     * 
     * @param mail the new mail to be processed
     *
     * @throws IllegalStateException when this method is called before the processor lists have been closed
     *                                  or the spool has been initialized
     */
    public void service(MailImpl mail) throws MessagingException {
        if (spool == null) {
            throw new IllegalStateException("Attempt to service mail before the spool has been set to a non-null value");
        }

        if (!listsClosed) {
            throw new IllegalStateException("Attempt to service mail before matcher/mailet lists have been closed");
        }

        if (getLogger().isDebugEnabled()) {
            getLogger().debug("Servicing mail: " + mail.getName());
        }
        //  unprocessed is an array of Lists of Mail objects