quotefilter.java

Jive是基于JSP/JAVA技术构架的一个大型BBS论坛系统,这是Jive论坛2.6版本的源程序

/**
 * $RCSfile: QuoteFilter.java,v $
 * $Revision: 1.2 $
 * $Date: 2002/04/01 17:50:14 $
 *
 * Copyright (C) 1999-2002 CoolServlets, Inc. All rights reserved.
 *
 * This software is the proprietary information of CoolServlets, Inc.
 * Use is subject to license terms.
 */

package com.jivesoftware.forum.filter;

import com.jivesoftware.forum.*;
import com.jivesoftware.util.StringUtils;

import java.io.*;
import java.util.*;

/**
 * A ForumMessageFilter that highlights quoted messages
 * based upon the level of indentation - very similar to
 * how groups.google.com highlights quotes.
 *
 * @author Bruce Ritchie
 */
public class QuoteFilter extends ForumMessageFilter {

    private ArrayList quoteColors;
    private char quoteChar;
    private boolean reformatTextEnabled;

    public QuoteFilter() {
        quoteColors = new ArrayList();

        quoteColors.add("#660066");
        quoteColors.add("#007777");
        quoteColors.add("#3377ff");
        quoteColors.add("#669966");
        quoteColors.add("#660000");

        quoteChar = '>';
        reformatTextEnabled = false;
    }

    /**
     * Clones a new filter that will have the same properties and that
     * will wrap around the specified message.
     *
     * @param message the ForumMessage to wrap the new filter around.
     */
    public ForumMessageFilter clone(ForumMessage message){
        QuoteFilter filter         = new QuoteFilter();
        filter.quoteColors         = quoteColors;
        filter.reformatTextEnabled = reformatTextEnabled;
        filter.quoteChar           = quoteChar;
        filter.message             = message;
        return filter;
    }

    public boolean isCacheable() {
        return true;
    }

    //FROM THE FORUMMESSAGE INTERFACE//

    /**
     * Returns the subject of the message with URLs changed to working links if
     * filtering on the subject is enabled.
     *
     * @return the filtered message subject.
     */
    public String getSubject() {
        return message.getSubject();
    }

    /**
     * Returns the body of the message with quoted lines quoted appropriately.
     *
     * @return the filtered message body.
     */
    public String getBody() {
        return parseQuotes(message.getBody());
    }

    //OTHER METHODS//

    public String getQuoteColors() {
        StringBuffer sb = new StringBuffer();

        for(int x=0; x < quoteColors.size(); x++) {
            sb.append(quoteColors.get(x).toString());
            if (x != quoteColors.size()-1) {
                sb.append(",");
            }
        }

        return sb.toString();
    }

    public void setQuoteColors(String prefix) {
        if (prefix != null) {
            quoteColors = new ArrayList();
            StringTokenizer st = new StringTokenizer(prefix, ",");

            while (st.hasMoreTokens()) {
                quoteColors.add(st.nextToken());
            }
        }
    }

    public boolean isReformatTextEnabled() {
        return reformatTextEnabled;
    }

    public void setReformatTextEnabled(boolean enabled) {
        reformatTextEnabled = enabled;
    }

    public String getQuoteChar() {
        return new Character(quoteChar).toString();
    }

    public void setQuoteChar(String c) {
        if (c != null) {
            quoteChar = c.trim().charAt(0);
        }
    }

    /**
     * This method takes a string which may contain quotes lines
     * and quotes the lines accordingly.  It does this
     * by adding the prefix line postfix according to the appropriate
     * quote level. An arbitrary level of quotes are available to be set, and
     * once those are used up it restarts from the beginning of the list
     *
     * @param input the text to be converted.
     * @returns the input string with the quoted lines handled accordingly.
     */
    private String parseQuotes(String input) {
        // Check if the string is null or zero length -- if so, return
        // what was sent in.
        if (input == null || input.length() == 0) {
            return input;
        }

        StringBuffer sb = new StringBuffer(input.length() + 512);
        BufferedReader br = new BufferedReader(new StringReader(input), 1024);
        ArrayList lines = new ArrayList();
        String line;
        char chars[];

        try {
            while ((line = br.readLine()) != null) {
                lines.add(line);
            }
            br.close();
        }
        catch (IOException e) { /* ignore */ }

        // correct text formatting if requested
        if (reformatTextEnabled) {
            reformatText(lines);
        }

        for (int c = 0; c < lines.size(); c++) {
            line = (String) lines.get(c);
            chars = StringUtils.replace(line, "&gt;", ">").toCharArray();

            if (isQuoted(chars)) {
                int count = countQuotes(chars) - 1;
                sb.append("<font color=\"");
                sb.append(quoteColors.get(count % quoteColors.size()).toString());
                sb.append("\">");
                sb.append(line);

                // for all following lines that have the same quote level
                // just append them to the buffer, we'll append the quotePostfix
                // at the end. This saves on needless html being generated and
                // reduces the size of the final html page. (Every little bit
                // counts)
                for (int g = c+1; g < lines.size(); g++) {
                    line = (String) lines.get(g);
                    chars = StringUtils.replace(line, "&gt;", ">").toCharArray();

                    if (isQuoted(chars) && (countQuotes(chars) - 1 == count)) {
                        sb.append("\n").append(line);
                        c = g;
                    }
                    else {
                        break;
                    }
                }
                sb.append("</font>").append("\n");
            }
            else {
                sb.append(line).append("\n");
            }
        }

        return sb.toString();
    }

    /**
     * This method takes a list of strings (one per line) and
     * through some heuristics attempts to correct for badly wrapped
     * lines.<p>
     *
     * This is allows for: <p>
     *
     * <ul>
     * <li>Making the text easier to read</li>
     * <li>Restoring the text format as close as possible to the original
     * formatting of the text prior to being reformatted by a MUA such as
     * Microsoft Outlook. MUA's often wrap lines of length > 76 characters
     * regardless of whether they are quoted or not.</li>
     * </ul>
     *
     * @param lines an arraylist of strings, one line/arraylist entry
     */
    private void reformatText(ArrayList lines) {
        char chars[];
        int count;
        int readAhead;
        boolean isHTMLFilterActive = false;

        for (int c = 0; c < lines.size(); c++) {
            chars = getLineAsChar(lines, c);

            // if this isn't a quoted line, skip it
            if (!isQuoted(chars)) {
                continue;
            }

            // check to see if we substituted any &gt; text
            if (chars.length < ((String) lines.get(c)).length()) {
                isHTMLFilterActive = true;
            }

            count        = countQuotes(chars);
            readAhead    = (lines.size() <= c + count + 1) ? lines.size() : c + count + 1;
            LinkedList l = new LinkedList();

            // For each quoted line, read ahead (n-1 quotes) lines to see
            // if the following lines are actually wrapped text from the
            // current quoted line.
            //
            // Notes: - If any of the following lines do not have < n quotes
            //        (no quote acceptable), they are not wrapped text. However
            //        if prior following lines fulfill all the other criteria,
            //        they are wrapped text
            //        - If any of the following lines have more than 2 words,
            //        they are not wrapped text
            //        - If any consecutive following lines have the same number
            //        of quotes, they are not wrapped text
            //        - If any of the following lines have less quotes than the
            //        previous following lines, they are not wrapped text
            //        - If the following line has no characters, they are not
            //        wrapped text
            for (int g = c+1; g < readAhead; g++) {
                chars = getLineAsChar(lines, g);
                l.addLast(chars);

                // rule 1
                if (isQuoted(chars) && countQuotes(chars) > count) {
                    // System.err.println("Too many quotes - " + new String(chars));
                    l.removeLast();
                    break;
                }
                // rule 2
                if (countWords(chars) > 2) {
                    // System.err.println("Too many words - " + new String(chars));
                    l.removeLast();
                    break;

                }
                // rule 3
                if (countQuotes(chars) == count) {
                    // System.err.println("same number of quotes - " + new String(chars));
                    l.removeLast();
                    break;
                }
                // rule 4
                if (!checkQuoteConsistency(l)) {
                    // System.err.println("Quote Inconsistent - " + new String(chars));
                    l.removeLast();
                    break;
                }
                // rule 5
                if (new String(chars).trim().length() < 1) {
                    // System.err.println("Empty line - " + new String(chars));
                    l.removeLast();
                    break;
                }
            }

            // we have wrapped text
            if (l.size() > 0) {
                Iterator iter = l.iterator();
                StringBuffer sb = new StringBuffer(l.size()+1 * 80);
                String line = (String) lines.get(c);

                if (isHTMLFilterActive) {
                    line = StringUtils.replace(line, ">", "&gt;");
                }

                sb.append(line);

                while (iter.hasNext()) {
                    chars = (char[]) iter.next();
                    sb.append(" ");
                    sb.append(stripQuotes(chars));
                    lines.remove(c+1);
                }

                lines.set(c, sb.toString());
            }
        }
    }

    private char[] getLineAsChar(ArrayList lines, int number) {
        String line = (String) lines.get(number);
        return StringUtils.replace(line, "&gt;", ">").toCharArray();
    }

    private int countWords(char[] chars) {
        String line = stripQuotes(chars).trim();
        int count = 0;

        for (int x=0; x < line.length(); x++) {
            if (line.charAt(x) == ' ') {
                count++;
            }
        }

        return count + 1;
    }

    private boolean checkQuoteConsistency(LinkedList l) {

        for (int c = l.size()-1; c > 0; c--) {
            for (int g = 0; g < c; g++) {
                if (countQuotes((char[]) l.get(c)) < countQuotes((char[]) l.get(g))) {
                    return false;
                }
            }
        }
        return true;
    }

    private boolean isQuoted(char[] chars) {
        for (int c = 0; c < chars.length; c++) {
            if (chars[c] == quoteChar) {
                return true;
            }
            else if (chars[c] != ' ') {
                return false;
            }
        }

        return false;
    }

    private int countQuotes(char[] chars) {
        int quoteCount = 0;

        for (int c = 0; c < chars.length; c++) {
            if (chars[c] == quoteChar) {
                quoteCount++;
            }
            else if (chars[c] == ' ') {
                continue;
            }
            else {
                return quoteCount;
            }
        }

        return quoteCount;
    }

    private String stripQuotes(char[] line) {
        StringBuffer sb = new StringBuffer(new String(line));
        boolean start = false;

        for (int c = 0; c < sb.length(); c++) {
            if (!start && sb.charAt(c) == quoteChar) {
                sb.deleteCharAt(c);
                if (c > 0) {
                    c--;
                }
            }
            else if (!start && sb.charAt(c) != ' ') {
                start = true;
            }
        }

        return sb.toString().trim();
    }
}