nntphandler.java

邮件服务器系统 支持SMTP POP3 是著名的Apache写 有一定的参考价值

        }
    }

    /**
     * Executes the HEAD command.  Sets the current article pointer,
     * returns article information and headers.
     *
     * @param the argument passed in to the HEAD command,
     *        which should be an article number or message id.
     *        If no parameter is provided, the current selected
     *        article is used.
     */
    private void doHEAD(String param) {
        // section 9.2.2
        NNTPArticle article = null;
        if (isMessageId(param)) {
            article = theConfigData.getNNTPRepository().getArticleFromID(param);
            if ( article == null ) {
                writeLoggedFlushedResponse("430 no such article");
                return;
            } else {
                StringBuffer respBuffer =
                    new StringBuffer(64)
                            .append("221 0 ")
                            .append(param);
                writeLoggedFlushedResponse(respBuffer.toString());
            }
        } else {
            int newArticleNumber = currentArticleNumber;
            if ( group == null ) {
                writeLoggedFlushedResponse("412 no newsgroup selected");
                return;
            } else {
                if ( param == null ) {
                    if ( currentArticleNumber < 0 ) {
                        writeLoggedFlushedResponse("420 no current article selected");
                        return;
                    } else {
                        article = group.getArticle(currentArticleNumber);
                    }
                }
                else {
                    newArticleNumber = Integer.parseInt(param);
                    article = group.getArticle(newArticleNumber);
                }
                if ( article == null ) {
                    writeLoggedFlushedResponse("423 no such article number in this group");
                    return;
                } else {
                    currentArticleNumber = newArticleNumber;
                    String articleID = article.getUniqueID();
                    if (articleID == null) {
                        articleID = "<0>";
                    }
                    StringBuffer respBuffer =
                        new StringBuffer(128)
                                .append("221 ")
                                .append(article.getArticleNumber())
                                .append(" ")
                                .append(articleID);
                    writeLoggedFlushedResponse(respBuffer.toString());
                }
            }
        }
        if (article != null) {
            writer.flush();
            article.writeHead(new ExtraDotOutputStream(outs));
            writeLoggedFlushedResponse(".");
        }
    }

    /**
     * Executes the ARTICLE command.  Sets the current article pointer,
     * returns article information and contents.
     *
     * @param the argument passed in to the ARTICLE command,
     *        which should be an article number or message id.
     *        If no parameter is provided, the current selected
     *        article is used.
     */
    private void doARTICLE(String param) {
        // section 9.2.1
        NNTPArticle article = null;
        if (isMessageId(param)) {
            article = theConfigData.getNNTPRepository().getArticleFromID(param);
            if ( article == null ) {
                writeLoggedFlushedResponse("430 no such article");
                return;
            } else {
                StringBuffer respBuffer =
                    new StringBuffer(64)
                            .append("220 0 ")
                            .append(param);
                writeLoggedResponse(respBuffer.toString());
            }
        } else {
            int newArticleNumber = currentArticleNumber;
            if ( group == null ) {
                writeLoggedFlushedResponse("412 no newsgroup selected");
                return;
            } else {
                if ( param == null ) {
                    if ( currentArticleNumber < 0 ) {
                        writeLoggedFlushedResponse("420 no current article selected");
                        return;
                    } else {
                        article = group.getArticle(currentArticleNumber);
                    }
                }
                else {
                    newArticleNumber = Integer.parseInt(param);
                    article = group.getArticle(newArticleNumber);
                }
                if ( article == null ) {
                    writeLoggedFlushedResponse("423 no such article number in this group");
                    return;
                } else {
                    currentArticleNumber = newArticleNumber;
                    String articleID = article.getUniqueID();
                    if (articleID == null) {
                        articleID = "<0>";
                    }
                    StringBuffer respBuffer =
                        new StringBuffer(128)
                                .append("220 ")
                                .append(article.getArticleNumber())
                                .append(" ")
                                .append(articleID);
                    writeLoggedFlushedResponse(respBuffer.toString());
                }
            }
        }
        if (article != null) {
            writer.flush();
            article.writeArticle(new ExtraDotOutputStream(outs));
            writeLoggedFlushedResponse(".");
        }
    }

    /**
     * Advances the current article pointer to the next article in the group.
     *
     * @param argument the argument passed in with the NEXT command
     */
    private void doNEXT(String argument) {
        // section 9.1.1.3.1
        if ( argument != null ) {
            writeLoggedFlushedResponse("501 Syntax error - unexpected parameter");
        } else if ( group == null ) {
            writeLoggedFlushedResponse("412 no newsgroup selected");
        } else if ( currentArticleNumber < 0 ) {
            writeLoggedFlushedResponse("420 no current article has been selected");
        } else if ( currentArticleNumber >= group.getLastArticleNumber() ) {
            writeLoggedFlushedResponse("421 no next article in this group");
        } else {
            currentArticleNumber++;
            NNTPArticle article = group.getArticle(currentArticleNumber);
            StringBuffer respBuffer =
                new StringBuffer(64)
                        .append("223 ")
                        .append(article.getArticleNumber())
                        .append(" ")
                        .append(article.getUniqueID());
            writeLoggedFlushedResponse(respBuffer.toString());
        }
    }

    /**
     * Moves the currently selected article pointer to the article
     * previous to the currently selected article in the selected group.
     *
     * @param argument the argument passed in with the LAST command
     */
    private void doLAST(String argument) {
        // section 9.1.1.2.1
        if ( argument != null ) {
            writeLoggedFlushedResponse("501 Syntax error - unexpected parameter");
        } else if ( group == null ) {
            writeLoggedFlushedResponse("412 no newsgroup selected");
        } else if ( currentArticleNumber < 0 ) {
            writeLoggedFlushedResponse("420 no current article has been selected");
        } else if ( currentArticleNumber <= group.getFirstArticleNumber() ) {
            writeLoggedFlushedResponse("422 no previous article in this group");
        } else {
            currentArticleNumber--;
            NNTPArticle article = group.getArticle(currentArticleNumber);
            StringBuffer respBuffer =
                new StringBuffer(64)
                        .append("223 ")
                        .append(article.getArticleNumber())
                        .append(" ")
                        .append(article.getUniqueID());
            writeLoggedFlushedResponse(respBuffer.toString());
        }
    }

    /**
     * Selects a group to be the current newsgroup.
     *
     * @param group the name of the group being selected.
     */
    private void doGROUP(String groupName) {
        if (groupName == null) {
            writeLoggedFlushedResponse("501 Syntax error - missing required parameter");
            return;
        }
        NNTPGroup newGroup = theConfigData.getNNTPRepository().getGroup(groupName);
        // section 9.1.1.1
        if ( newGroup == null ) {
            writeLoggedFlushedResponse("411 no such newsgroup");
        } else {
            group = newGroup;
            // if the number of articles in group == 0
            // then the server may return this information in 3 ways, 
            // The clients must honor all those 3 ways.
            // our response is: 
            // highWaterMark == lowWaterMark and number of articles == 0
            int articleCount = group.getNumberOfArticles();
            int lowWaterMark = group.getFirstArticleNumber();
            int highWaterMark = group.getLastArticleNumber();

            // Set the current article pointer.  If no
            // articles are in the group, the current article
            // pointer should be explicitly unset.
            if (articleCount != 0) {
                currentArticleNumber = lowWaterMark;
            } else {
                currentArticleNumber = -1;
            }
            StringBuffer respBuffer =
                new StringBuffer(128)
                        .append("211 ")
                        .append(articleCount)
                        .append(" ")
                        .append(lowWaterMark)
                        .append(" ")
                        .append(highWaterMark)
                        .append(" ")
                        .append(group.getName())
                        .append(" group selected");
            writeLoggedFlushedResponse(respBuffer.toString());
        }
    }

    /**
     * Lists the extensions supported by this news server.
     */
    private void doLISTEXTENSIONS() {
        // 8.1.1
        writeLoggedResponse("202 Extensions supported:");
        writeLoggedResponse("LISTGROUP");
        writeLoggedResponse("AUTHINFO");
        writeLoggedResponse("OVER");
        writeLoggedResponse("XOVER");
        writeLoggedResponse("HDR");
        writeLoggedResponse("XHDR");
        writeLoggedFlushedResponse(".");
    }

    /**
     * Informs the server that the client is a newsreader.
     *
     * @param argument the argument passed in with the MODE READER command
     */
    private void doMODEREADER(String argument) {
        // 7.2
        writeLoggedFlushedResponse(theConfigData.getNNTPRepository().isReadOnly()
                       ? "201 Posting Not Permitted" : "200 Posting Permitted");
    }

    /**
     * Informs the server that the client is a news server.
     *
     * @param argument the argument passed in with the MODE STREAM command
     */
    private void doMODESTREAM(String argument) {
        // 7.2
        writeLoggedFlushedResponse("500 Command not understood");
    }

    /**
     * Gets a listing of article numbers in specified group name
     * or in the already selected group if the groupName is null.
     *
     * @param groupName the name of the group to list
     */
    private void doLISTGROUP(String groupName) {
        // 9.5.1.1.1
        if (groupName==null) {
            if ( group == null) {
                writeLoggedFlushedResponse("412 no news group currently selected");
                return;
            }
        }
        else {
            group = theConfigData.getNNTPRepository().getGroup(groupName);
            if ( group == null ) {
                writeLoggedFlushedResponse("411 no such newsgroup");
                return;
            }
        }
        if ( group != null ) {
            // this.group = group;

            // Set the current article pointer.  If no
            // articles are in the group, the current article
            // pointer should be explicitly unset.
            if (group.getNumberOfArticles() > 0) {
                currentArticleNumber = group.getFirstArticleNumber();
            } else {
                currentArticleNumber = -1;
            }

            writeLoggedFlushedResponse("211 list of article numbers follow");

            Iterator iter = group.getArticles();
            while (iter.hasNext()) {
                NNTPArticle article = (NNTPArticle)iter.next();
                writeLoggedResponse(article.getArticleNumber() + "");
            }
            writeLoggedFlushedResponse(".");
        }
    }

    /**
     * Handles the LIST OVERVIEW.FMT command.  Not supported.
     */
    private void doLISTOVERVIEWFMT() {
        // 9.5.3.1.1
        writeLoggedFlushedResponse("215 Information follows");
        String[] overviewHeaders = theConfigData.getNNTPRepository().getOverviewFormat();
        for (int i = 0;  i < overviewHeaders.length; i++) {
            writeLoggedResponse(overviewHeaders[i]);
        }
        writeLoggedFlushedResponse(".");
    }

    /**
     * Handles the PAT command.  Not supported.
     *
     * @param argument the argument passed in with the PAT command
     */
    private void doPAT(String argument) {
        // 9.5.3.1.1 in draft-12
        writeLoggedFlushedResponse("500 Command not recognized");
    }

    /**
     * Get the values of the headers for the selected newsgroup, 
     * with an optional range modifier.
     *
     * @param argument the argument passed in with the XHDR command.