pop3.java

Rapla是一个灵活的多用户资源管理系统。它提供的一些功能有：日历GUI

        PopStatus status = new PopStatus();
        send("LIST");        // Issue the LIST command

        recvN(status);     // read the response
        Parse(status,2);

        return status;
    }

    /** Gets the uidl of the specified mail msg.
     *  @param  msgnum     message number
     *  @return PopStatus: result of this operation
     */
    public synchronized PopStatus uidl(int msgnum) {
        PopStatus status = new PopStatus();
        send("UIDL " + msgnum);     // Issue the UIDL msgnum command
        status._Response = recv();  // read the response
        Parse(status,2);

        return status;
    }

    /** Gets a list of messages and the <code>UIDL</code> of
     *  each one.
     *  <code>UIDL</code> is a message identifier that is
     *  garanteed to remain the same even across different
     *  sessions.
     *  @return PopStatus: result of this operation
     */
    public synchronized PopStatus uidl() {

        PopStatus status = new PopStatus();
        send("UIDL");      // Issue the UIDL command

        recvN(status);     // read the responses
        Parse(status,2);

        return status;
    }

    /**  Gets the contents of a mail message.
     *  The array of strings obtained are the lines of the
     *  specified mail message.
     *  The lines have <code>CR/LF</code> stripped, any leading
     *  <code>"."</code> fixed up and the ending <code>"."</code>
     *  removed.<br>
     *  The array can be retrieved with the status.Responses() method.
     *  The <code>+OK</code> or <code>-ERR</code> status line is
     *  returned.
     *  @param msgnum      message number
     *  @return PopStatus: result of this operation
     */
    public synchronized PopStatus retr(int msgnum) {

        PopStatus status = new PopStatus();
        send("RETR " + msgnum);        // Issue the RETR n command

        // This may produce more than one response so we call the
        // recvN method and save an array of strings in status._Responses.
        recvN(status);     // read the response
        // The initial string that contains the status is in the
        // status._Response state variable.
        Parse(status,2);

        return status;
    }


    /** Gets the top n lines of a mail message.
     *  The array of strings obtained are the lines of the
     *  mail headers and the top N lines of the indicated mail msg.
     *  The lines have <code>CR/LF</code> striped, any leading
     *  <code>"."</code> fixed up and the ending <code>"."</code>
     *  removed. <br>
     *  The array can be retrieved with status.Responses() method.
     *  The <code>+OK</code> or <code>-ERR</code> status line is
     *  returned.
     *  @param  msgnum     the message number
     *  @param  n          how many body lines should be retrieved.
     *     If <code>n=0</code>, you'll get just the headers,
     *     unfortunately I've bumped into a buggy Pop3 server that
     *     didn't like zeroes, so I suggest to use <code>n=1</code>
     *     if you want just headers.
     *  @return PopStatus: result of this operation
     */
    public synchronized PopStatus top(int msgnum, int n) {

        PopStatus status = new PopStatus();
        send("TOP " + msgnum + " " + n); // Issue the TOP msgnum n command

        // This may produce more than one response so we call the
        // recvN method and set multiline output into _Responses
        recvN(status);     // read the response

        Parse(status,2);

        return status;
    }


    /** Marks the mail message for deletion
     *  This mail message will be deleted when QUIT is issued.
     *  If you lose the connection the message is not deleted.
     *  @param msgnum      a message number
     *  @return PopStatus: result of this operation
     *  @see  #rset()
     */
    public synchronized PopStatus dele(int msgnum) {
        PopStatus status = new PopStatus();
        send("DELE " + msgnum);        // Issue the DELE n command

        status._Response = recv();     // read the response
        Parse(status,2);

        return status;
    }

    /** Resets the mail messages that have been marked for deletion.
     *  Nothing will be deleted if QUIT is issued next.
     *  @return PopStatus: result of this operation
     *  @see  #dele(int)
     */
    public synchronized PopStatus rset() {
        PopStatus status = new PopStatus();
        send("RSET");        // Issue the RSET command

        status._Response = recv();     // read the response
        Parse(status,2);

        return status;
    }

    /** Does not do anything but it will keep the server active.
     *  @return PopStatus: result of this operation
     */
    public synchronized PopStatus noop() {

        PopStatus status = new PopStatus();
        send("NOOP");        // Issue the NOOP command

        status._Response = recv();     // read the response
        Parse(status,2);

        return status;
    }

    /** Returns the number of messages on the server.
     *  This value is set by an internal <code>STAT</code>
     *  issued at login.
     *  @return the number of messages on this server.
     *  @see    #get_TotalSize()
     */
    public int get_TotalMsgs() {
        return _TotalMsgs;
    }

    /** Returns the size of messages on the server.
     *  This value is set by an internal <code>STAT</code>
     *  issued at login.
     *  @return the total size of messages on this server.
     *  @see    #get_TotalMsgs()
     */
    public int get_TotalSize() {
        return _TotalSize;
    }

    /** Returns the contents of a mail message and append it to the
     *  specified mail file.
     *  It will internally call <code>RETR</code> and then write
     *  the results to the specified file.
     *  @param  filename   the name of the file to be extended
     *  @param  msgnum     a message number
     *  @return PopStatus: result of this operation
     */
    public synchronized  PopStatus appendFile(String filename, int msgnum) {
        PopStatus status = new PopStatus();

        String[] contents;

        send("RETR " + msgnum);         // RETR n will return the contents
        // of message n

        recvN(status);     // read the response
        Parse(status,2);
        if (status._OK) {
            RandomAccessFile openfile;
            try {
                openfile = new RandomAccessFile(filename,"rw");
            } catch (IOException e) {
                status._OK = false;
                status._Response = "-ERR File open failed";
                return status;
            }
            Date datestamp = new Date();
            contents = status.Responses();
            try {
                openfile.seek(openfile.length());
                openfile.writeBytes("From - " + datestamp.toString() + "\r\n");
                for(int i=0; i<contents.length;i++) {

                    openfile.writeBytes(contents[i]+"\r\n");
                    //openfile.writeByte((int)'\r');  // add CR LF
                    //openfile.writeByte((int)'\n');
                }
                openfile.close();

            } catch (IOException e) {
                status._OK = false;
                status._Response = "-ERR File write failed";
                return status;
            }
        }
        status._OK = true;
        return status;
    }

    /** Parses the response to a previously sent command from the server.
     * It will set boolean status._OK true if it returned <code>+OK</code>
     * and return an array of strings each representing a white space
     * delimited token. The remainder of the response after
     * <code>maxToParse</code> is returned as a single String.
     */
    String[] Parse(PopStatus status, int maxToParse) {
        String[] tokens = null;

        status._OK = false;
        String response = status._Response;
        if (response != null) {
            int i=0;
            int max;
            if (response.trim().startsWith("+OK"))
                status._OK = true;
            else
                debug(response);
            // This will break the line into a set of tokens.
            StringTokenizer st = new StringTokenizer(response);
            //tokens = new String[st.countTokens()];
            if (maxToParse == -1)
                max = st.countTokens();
            else
                max = maxToParse;
            tokens = new String[max+1];
            while (st.hasMoreTokens() && i < max) {
                tokens[i] = new String(st.nextToken());
                //debug("Token " + i + "= '" + tokens[i] + "'");
                i++;
            }
            // Now get any remaining tokens as a single string
            if (st.hasMoreTokens()) {
                StringBuffer rest = new StringBuffer(st.nextToken());
                while (st.hasMoreTokens() )
                    rest.append(" " + st.nextToken());
                tokens[max] = new String(rest);
                //debug("Token " + max + "= '" + tokens[max] + "'");
            }
        }
        return tokens;
    }

    /** Sends the passed command to the server.
     */
    void send (String cmdline) {
        debug(">> " + cmdline);
        LastCmd = cmdline;    // Save command for error msg

        try {
            // Write string as a set of bytes
            serverOutputStream.writeBytes(cmdline + "\r\n");
            _StatusOK = true;
        } catch (IOException i){
            System.err.println("Caught exception while sending command to server");
            _StatusOK = false;

        } catch (Exception e) {
            System.err.println("Send: Unexpected exception: " + e.toString());
            _StatusOK = false;
        }
    }

    /** Gets the next response to a previously sent command from the server.
     */
    String recv() {
        //debug("entered recv");

        String line = "";
        if ( ! _StatusOK  ) {
            line = "-ERR Failed sending command to server";
            return line;
        }
        // send() has written a command to the
        // server so now we will try to read the result
        try {
            line = serverInputStream.readLine();
            debug("<<" + line);
        } catch (IOException i){
            System.err.println("Caught exception while reading");
            line = "-ERR Caught IOException while reading from server";
        } catch (Exception e) {
            System.err.println("Unexpected exception: " + e.toString());
            line = "-ERR Unexpected exception while reading from server";
        }
        if (line == null)       {       // prevent crash if reading a null line
            debug("Read a null line from server");
            line = "-ERR <NULL>";
        }
        if (line.trim().startsWith("-ERR")) {
            debug("Result from server has error!");
            debug("Sent:     '" + LastCmd + "'");
            debug("Received: '" + line + "'");
            return line;
        } else {
            if (line.trim().startsWith("+OK")) {
                return line;
            } else {
                debug("Received strange response");
                debug("'" + line + "'");
                line = "-ERR Invalid response";
                return line;
            }
        }
    }

    /** Gets the responses to a previously sent command from the server.
     * This is used when more than one line is expected.
     * The last line of output should be <code>".\r\n"</code>
     */
    void recvN(PopStatus status) {
        debug("entered recvN");
        Vector v = new Vector(100,100);
        String line = "";
        
        // send() has written a command to the
        // server so now we will try to read the result
        try {
            boolean done = false;
            int linenum=0;
            while (!done) {
                line = serverInputStream.readLine();
                linenum++;
                debug("<<" + line.length() + " '" + line +"'");
                if (linenum == 1) { // process the initial line
                    if (line.trim().startsWith("-ERR ")) {
                        debug("Result from server has error!");
                        debug("Sent:     '" + LastCmd + "'");
                        debug("Received: '" + line + "'");
                        done = true;
                        status._Response = line;
                    } else {
                        if (line.trim().startsWith("+OK")) {
                            //Everything looks OK
                            status._Response = line;
                        } else {
                            debug("Received strange response");
                            debug("'" + line + "'");
                            done = true;
                            status._Response = "-ERR Invalid response";
                        }
                    }
                } else {
                    // process line 2 - n
                    if (line.startsWith(".")) {
                        if (line.length() == 1)
                            done = true;
                        else
                            v.addElement(line.substring(1));
                    } else
                        v.addElement(line);
                }

            }   // end of while(!done)
        } catch (IOException i){
            System.err.println("Caught exception while reading");
            status._Response = "-ERR Caught IOException while reading from server";
        } catch (Exception e) {
            System.err.println("Unexpected exception: " + e.toString());
            status._Response = "-ERR Unexpected exception while reading from server";
        }

        status._Responses = new String[v.size()];
        v.copyInto(status._Responses);
        return;
    }

    /** Sets debug on or off.
     *  Debug messages are written to standard error.
     *  @param OnOff  true to set on debugging, false to
     *      shut it up.
     */
    public void setDebugOn(boolean OnOff) {
        debugOn = OnOff;
    }

    /** If debugOn switch is set, display debug info.
     *  @param   debugstr  a debug message
     */
    public void debug(String debugstr) {
        if (debugOn) {
            System.err.println(debugstr);
        }
    }

    //-------------------------------------------------------

} // end of Class Pop3