pop3handler.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

        // Clear config data
        theConfigData = null;
    }

    /**
     * Implements a "stat".  If the handler is currently in
     * a transaction state, this amounts to a rollback of the
     * mailbox contents to the beginning of the transaction.
     * This method is also called when first entering the
     * transaction state to initialize the handler copies of the
     * user inbox.
     *
     */
    private void stat() {
        userMailbox = new ArrayList();
        userMailbox.add(DELETED);
        try {
            for (Iterator it = userInbox.list(); it.hasNext(); ) {
                String key = (String) it.next();
                Mail mc = userInbox.retrieve(key);
                // Retrieve can return null if the mail is no longer in the store.
                // In this case we simply continue to the next key
                if (mc == null) {
                    continue;
                }
                userMailbox.add(mc);
            }
        } catch(MessagingException e) {
            // In the event of an exception being thrown there may or may not be anything in userMailbox
            getLogger().error("Unable to STAT mail box ", e);
        }
        finally {
            backupUserMailbox = (ArrayList) userMailbox.clone();
        }
    }

    /**
     * Reads a line of characters off the command line.
     *
     * @return the trimmed input line
     * @throws IOException if an exception is generated reading in the input characters
     */
    final String readCommandLine() throws IOException {
        for (;;) try {
            String commandLine = in.readLine();
            if (commandLine != null) {
                commandLine = commandLine.trim();
            }
            return commandLine;
        } catch (CRLFTerminatedReader.TerminationException te) {
            writeLoggedFlushedResponse("-ERR Syntax error at character position " + te.position() + ". CR and LF must be CRLF paired.  See RFC 1939 #3.");
        }
    }

    /**
     * This method parses POP3 commands read off the wire in handleConnection.
     * Actual processing of the command (possibly including additional back and
     * forth communication with the client) is delegated to one of a number of
     * command specific handler methods.  The primary purpose of this method is
     * to parse the raw command string to determine exactly which handler should
     * be called.  It returns true if expecting additional commands, false otherwise.
     *
     * @param rawCommand the raw command string passed in over the socket
     *
     * @return whether additional commands are expected.
     */
    private boolean parseCommand(String rawCommand) {
        if (rawCommand == null) {
            return false;
        }
        boolean returnValue = true;
        String command = rawCommand;
        StringTokenizer commandLine = new StringTokenizer(command, " ");
        int arguments = commandLine.countTokens();
        if (arguments == 0) {
            return true;
        } else if(arguments > 0) {
            command = commandLine.nextToken().toUpperCase(Locale.US);
        }
        if (getLogger().isDebugEnabled()) {
            // Don't display password in logger
            if (!command.equals("PASS")) {
                getLogger().debug("Command received: " + rawCommand);
            } else {
                getLogger().debug("Command received: PASS <password omitted>");
            }
        }
        String argument = (String) null;
        if(arguments > 1) {
            argument = commandLine.nextToken();
        }
        String argument1 = (String) null;
        if(arguments > 2) {
            argument1 = commandLine.nextToken();
        }

        if (command.equals("USER")) {
            doUSER(command,argument,argument1);
        } else if (command.equals("PASS")) {
            doPASS(command,argument,argument1);
        } else if (command.equals("STAT")) {
            doSTAT(command,argument,argument1);
        } else if (command.equals("LIST")) {
            doLIST(command,argument,argument1);
        } else if (command.equals("UIDL")) {
            doUIDL(command,argument,argument1);
        } else if (command.equals("RSET")) {
            doRSET(command,argument,argument1);
        } else if (command.equals("DELE")) {
            doDELE(command,argument,argument1);
        } else if (command.equals("NOOP")) {
            doNOOP(command,argument,argument1);
        } else if (command.equals("RETR")) {
            doRETR(command,argument,argument1);
        } else if (command.equals("TOP")) {
            doTOP(command,argument,argument1);
        } else if (command.equals("QUIT")) {
            returnValue = false;
            doQUIT(command,argument,argument1);
        } else {
            doUnknownCmd(command,argument,argument1);
        }
        return returnValue;
    }

    /**
     * Handler method called upon receipt of a USER command.
     * Reads in the user id.
     *
     * @param command the command parsed by the parseCommand method
     * @param argument the first argument parsed by the parseCommand method
     * @param argument1 the second argument parsed by the parseCommand method
     */
    private void doUSER(String command,String argument,String argument1) {
        String responseString = null;
        if (state == AUTHENTICATION_READY && argument != null) {
            user = argument;
            state = AUTHENTICATION_USERSET;
            responseString = OK_RESPONSE;
        } else {
            responseString = ERR_RESPONSE;
        }
        writeLoggedFlushedResponse(responseString);
    }

    /**
     * Handler method called upon receipt of a PASS command.
     * Reads in and validates the password.
     *
     * @param command the command parsed by the parseCommand method
     * @param argument the first argument parsed by the parseCommand method
     * @param argument1 the second argument parsed by the parseCommand method
     */
    private void doPASS(String command,String argument,String argument1) {
        String responseString = null;
        if (state == AUTHENTICATION_USERSET && argument != null) {
            String passArg = argument;
            if (theConfigData.getUsersRepository().test(user, passArg)) {
                StringBuffer responseBuffer =
                    new StringBuffer(64)
                            .append(OK_RESPONSE)
                            .append(" Welcome ")
                            .append(user);
                responseString = responseBuffer.toString();
                state = TRANSACTION;
                writeLoggedFlushedResponse(responseString);
                userInbox = theConfigData.getMailServer().getUserInbox(user);
                stat();
            } else {
                responseString = ERR_RESPONSE + " Authentication failed.";
                state = AUTHENTICATION_READY;
                writeLoggedFlushedResponse(responseString);
            }
        } else {
            responseString = ERR_RESPONSE;
            writeLoggedFlushedResponse(responseString);
        }
    }

    /**
     * Handler method called upon receipt of a STAT command.
     * Returns the number of messages in the mailbox and its
     * aggregate size.
     *
     * @param command the command parsed by the parseCommand method
     * @param argument the first argument parsed by the parseCommand method
     * @param argument1 the second argument parsed by the parseCommand method
     */
    private void doSTAT(String command,String argument,String argument1) {
        String responseString = null;
        if (state == TRANSACTION) {
            long size = 0;
            int count = 0;
            try {
                for (Iterator i = userMailbox.iterator(); i.hasNext(); ) {
                    MailImpl mc = (MailImpl) i.next();
                    if (mc != DELETED) {
                        size += mc.getMessageSize();
                        count++;
                    }
                }
                StringBuffer responseBuffer =
                    new StringBuffer(32)
                            .append(OK_RESPONSE)
                            .append(" ")
                            .append(count)
                            .append(" ")
                            .append(size);
                responseString = responseBuffer.toString();
                writeLoggedFlushedResponse(responseString);
            } catch (MessagingException me) {
                responseString = ERR_RESPONSE;
                writeLoggedFlushedResponse(responseString);
            }
        } else {
            responseString = ERR_RESPONSE;
            writeLoggedFlushedResponse(responseString);
        }
    }

    /**
     * Handler method called upon receipt of a LIST command.
     * Returns the number of messages in the mailbox and its
     * aggregate size, or optionally, the number and size of
     * a single message.
     *
     * @param command the command parsed by the parseCommand method
     * @param argument the first argument parsed by the parseCommand method
     * @param argument1 the second argument parsed by the parseCommand method
     */
    private void doLIST(String command,String argument,String argument1) {
        String responseString = null;
        if (state == TRANSACTION) {
            if (argument == null) {
                long size = 0;
                int count = 0;
                try {
                    for (Iterator i = userMailbox.iterator(); i.hasNext(); ) {
                        MailImpl mc = (MailImpl) i.next();
                        if (mc != DELETED) {
                            size += mc.getMessageSize();
                            count++;
                        }
                    }
                    StringBuffer responseBuffer =
                        new StringBuffer(32)
                                .append(OK_RESPONSE)
                                .append(" ")
                                .append(count)
                                .append(" ")
                                .append(size);
                    responseString = responseBuffer.toString();
                    writeLoggedFlushedResponse(responseString);
                    count = 0;
                    for (Iterator i = userMailbox.iterator(); i.hasNext(); count++) {
                        MailImpl mc = (MailImpl) i.next();

                        if (mc != DELETED) {
                            responseBuffer =
                                new StringBuffer(16)
                                        .append(count)
                                        .append(" ")
                                        .append(mc.getMessageSize());
                            out.println(responseBuffer.toString());
                        }
                    }
                    out.println(".");
                    out.flush();
                } catch (MessagingException me) {
                    responseString = ERR_RESPONSE;
                    writeLoggedFlushedResponse(responseString);
                }
            } else {
                int num = 0;
                try {
                    num = Integer.parseInt(argument);
                    MailImpl mc = (MailImpl) userMailbox.get(num);
                    if (mc != DELETED) {
                        StringBuffer responseBuffer =
                            new StringBuffer(64)
                                    .append(OK_RESPONSE)
                                    .append(" ")
                                    .append(num)
                                    .append(" ")
                                    .append(mc.getMessageSize());
                        responseString = responseBuffer.toString();
                        writeLoggedFlushedResponse(responseString);
                    } else {
                        StringBuffer responseBuffer =
                            new StringBuffer(64)
                                    .append(ERR_RESPONSE)
                                    .append(" Message (")
                                    .append(num)
                                    .append(") already deleted.");
                        responseString = responseBuffer.toString();
                        writeLoggedFlushedResponse(responseString);
                    }
                } catch (IndexOutOfBoundsException npe) {
                    StringBuffer responseBuffer =
                        new StringBuffer(64)
                                .append(ERR_RESPONSE)
                                .append(" Message (")
                                .append(num)
                                .append(") does not exist.");
                    responseString = responseBuffer.toString();
                    writeLoggedFlushedResponse(responseString);
                } catch (NumberFormatException nfe) {
                    StringBuffer responseBuffer =
                        new StringBuffer(64)
                                .append(ERR_RESPONSE)
                                .append(" ")
                                .append(argument)
                                .append(" is not a valid number");
                    responseString = responseBuffer.toString();
                    writeLoggedFlushedResponse(responseString);
                } catch (MessagingException me) {
                    responseString = ERR_RESPONSE;
                    writeLoggedFlushedResponse(responseString);
               }
            }
        } else {
            responseString = ERR_RESPONSE;
            writeLoggedFlushedResponse(responseString);
        }
    }

    /**
     * Handler method called upon receipt of a UIDL command.
     * Returns a listing of message ids to the client.
     *
     * @param command the command parsed by the parseCommand method
     * @param argument the first argument parsed by the parseCommand method
     * @param argument1 the second argument parsed by the parseCommand method
     */
    private void doUIDL(String command,String argument,String argument1) {
        String responseString = null;
        if (state == TRANSACTION) {
            if (argument == null) {
                responseString = OK_RESPONSE + " unique-id listing follows";
                writeLoggedFlushedResponse(responseString);
                int count = 0;
                for (Iterator i = userMailbox.iterator(); i.hasNext(); count++) {
                    MailImpl mc = (MailImpl) i.next();
                    if (mc != DELETED) {
                        StringBuffer responseBuffer =
                            new StringBuffer(64)
                                    .append(count)
                                    .append(" ")
                                    .append(mc.getName());
                        out.println(responseBuffer.toString());
                    }
                }
                out.println(".");
                out.flush();
            } else {
                int num = 0;
                try {
                    num = Integer.parseInt(argument);
                    MailImpl mc = (MailImpl) userMailbox.get(num);
                    if (mc != DELETED) {
                        StringBuffer responseBuffer =
                            new StringBuffer(64)
                                    .append(OK_RESPONSE)
                                    .append(" ")
                                    .append(num)
                                    .append(" ")
                                    .append(mc.getName());
                        responseString = responseBuffer.toString();