htmlencoder.java

使用工具jublider开发的一个聊天室实现基本功能,

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 *
 * The contents of this file are subject to the Helma License
 * Version 2.0 (the "License"). You may not use this file except in
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 * http://adele.helma.org/download/helma/license.txt
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 * http://adele.helma.org/download/helma/license.txt:
 *

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    notice, this list of conditions and the following disclaimer.

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    the documentation and/or other materials provided with the
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    or "Hop", nor may "Helma" or "Hop" appear in their name, without
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package freecs.util;

import java.util.*;

/**
 * This is a utility class to encode special characters and do formatting
 * for HTML output.
 * @author Hannes Wallnoefer
 */
public final class HtmlEncoder {

    // transformation table for characters 128 to 255. These actually fall into two
    // groups, put together for efficiency: "Windows" chacacters 128-159 such as
    // "smart quotes", which are encoded to valid Unicode entities, and
    // valid ISO-8859 caracters 160-255, which are encoded to the symbolic HTML
    // entity. Everything >= 256 is encoded to a numeric entity.
    //
    // for mor on HTML entities see http://www.pemberley.com/janeinfo/latin1.html  and
    // ftp://ftp.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP1252.TXT
    //
    static final String[] transform =  {
        "€",   // 128
        "",           // empty string means character is undefined in unicode
        "‚",
        "ƒ",
        "„",
        "…",
        "†",
        "‡",
        "ˆ",
        "‰",
        "Š",
        "‹",
        "Œ",
        "",
        "Ž",
        "",
        "",
        "‘",
        "’",
        "“",
        "”",
        "•",
        "–",
        "—",
        "˜",
        "™",
        "š",
        "›",
        "œ",
        "",
        "ž",
        "Ÿ",  // 159
        " ",    // 160
        "¡",
        "¢",
        "£",
        "¤",
        "¥",
        "¦",
        "§",
        "¨",
        "©",
        "ª",
        "«",
        "¬",
        "­",
        "®",
        "¯",
        "°",
        "±",
        "²",
        "³",
        "´",
        "µ",
        "¶",
        "·",
        "¸",
        "¹",
        "º",
        "»",
        "¼",
        "½",
        "¾",
        "¿",
        "À",
        "Á",
        "Â",
        "Ã",
        "Ä",
        "Å",
        "Æ",
        "Ç",
        "È",
        "É",
        "Ê",
        "Ë",
        "Ì",
        "Í",
        "Î",
        "Ï",
        "Ð",
        "Ñ",
        "Ò",
        "Ó",
        "Ô",
        "Õ",
        "Ö",
        "×",
        "Ø",
        "Ù",
        "Ú",
        "Û",
        "Ü",
        "Ý",
        "Þ",
        "ß",
        "à",
        "á",
        "â",
        "ã",
        "ä",
        "å",
        "æ",
        "ç",
        "è",
        "é",
        "ê",
        "ë",
        "ì",
        "í",
        "î",
        "ï",
        "ð",
        "ñ",
        "ò",
        "ó",
        "ô",
        "õ",
        "ö",
        "÷",
        "ø",
        "ù",
        "ú",
        "û",
        "ü",
        "ý",
        "þ",
        "ÿ"    // 255
    };

    static final HashSet allTags = new HashSet();

    static {
        allTags.add("a");
        allTags.add("abbr");
        allTags.add("acronym");
        allTags.add("address");
        allTags.add("applet");
        allTags.add("area");
        allTags.add("b");
        allTags.add("base");
        allTags.add("basefont");
        allTags.add("bdo");
        allTags.add("bgsound");
        allTags.add("big");
        allTags.add("blink");
        allTags.add("blockquote");
        allTags.add("bq");
        allTags.add("body");
        allTags.add("br");
        allTags.add("button");
        allTags.add("caption");
        allTags.add("center");
        allTags.add("cite");
        allTags.add("code");
        allTags.add("col");
        allTags.add("colgroup");
        allTags.add("del");
        allTags.add("dfn");
        allTags.add("dir");
        allTags.add("div");
        allTags.add("dl");
        allTags.add("dt");
        allTags.add("dd");
        allTags.add("em");
        allTags.add("embed");
        allTags.add("fieldset");
        allTags.add("font");
        allTags.add("form");
        allTags.add("frame");
        allTags.add("frameset");
        allTags.add("h1");
        allTags.add("h2");
        allTags.add("h3");
        allTags.add("h4");
        allTags.add("h5");
        allTags.add("h6");
        allTags.add("head");
        allTags.add("html");
        allTags.add("hr");
        allTags.add("i");
        allTags.add("iframe");
        allTags.add("img");
        allTags.add("input");
        allTags.add("ins");
        allTags.add("isindex");
        allTags.add("kbd");
        allTags.add("label");
        allTags.add("legend");
        allTags.add("li");
        allTags.add("link");
        allTags.add("listing");
        allTags.add("map");
        allTags.add("marquee");
        allTags.add("menu");
        allTags.add("meta");
        allTags.add("nobr");
        allTags.add("noframes");
        allTags.add("noscript");
        allTags.add("object");
        allTags.add("ol");
        allTags.add("option");
        allTags.add("optgroup");
        allTags.add("p");
        allTags.add("param");
        allTags.add("plaintext");
        allTags.add("pre");
        allTags.add("q");
        allTags.add("s");
        allTags.add("samp");
        allTags.add("script");
        allTags.add("select");
        allTags.add("small");
        allTags.add("span");
        allTags.add("strike");
        allTags.add("strong");
        allTags.add("style");
        allTags.add("sub");
        allTags.add("sup");
        allTags.add("table");
        allTags.add("tbody");
        allTags.add("td");
        allTags.add("textarea");
        allTags.add("tfoot");
        allTags.add("th");
        allTags.add("thead");
        allTags.add("title");
        allTags.add("tr");
        allTags.add("tt");
        allTags.add("u");
        allTags.add("ul");
        allTags.add("var");
        allTags.add("wbr");
        allTags.add("xmp");
    }

    // HTML block tags need to suppress automatic newline to <br>
    // conversion around them to look good. However, they differ
    // in how many newlines around them should ignored. These sets
    // help to treat each tag right in newline conversion.
    static final HashSet internalTags = new HashSet();
    static final HashSet blockTags = new HashSet();
    static final HashSet semiBlockTags = new HashSet();

    static {
        // actual block level elements
        semiBlockTags.add("address");
        semiBlockTags.add("dir");
        semiBlockTags.add("div");
        semiBlockTags.add("table");

        blockTags.add("blockquote");
        blockTags.add("center");
        blockTags.add("dl");
        blockTags.add("fieldset");
        blockTags.add("form");
        blockTags.add("h1");
        blockTags.add("h2");
        blockTags.add("h3");
        blockTags.add("h4");
        blockTags.add("h5");
        blockTags.add("h6");
        blockTags.add("hr");
        blockTags.add("isindex");
        blockTags.add("ol");
        blockTags.add("p");
        blockTags.add("pre");
        blockTags.add("ul");

        internalTags.add("menu");
        internalTags.add("noframes");
        internalTags.add("noscript");

        /// to be treated as block level elements
        semiBlockTags.add("th");

        blockTags.add("br");
        blockTags.add("dd");
        blockTags.add("dt");
        blockTags.add("frameset");
        blockTags.add("li");
        blockTags.add("td");

        internalTags.add("tbody");
        internalTags.add("tfoot");
        internalTags.add("thead");
        internalTags.add("tr");
    }

    // set of tags that are always empty