jdk/src/share/classes/javax/swing/text/html/HTML.java
changeset 2 90ce3da70b43
child 1287 a04aca99c77a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/javax/swing/text/html/HTML.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,697 @@
+/*
+ * Copyright 1998-2005 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+package javax.swing.text.html;
+
+import java.io.*;
+import java.util.Hashtable;
+import javax.swing.text.AttributeSet;
+import javax.swing.text.StyleConstants;
+import javax.swing.text.StyleContext;
+
+/**
+ * Constants used in the <code>HTMLDocument</code>.  These
+ * are basically tag and attribute definitions.
+ *
+ * @author  Timothy Prinzing
+ * @author  Sunita Mani
+ *
+ */
+public class HTML {
+
+    /**
+     * Typesafe enumeration for an HTML tag.  Although the
+     * set of HTML tags is a closed set, we have left the
+     * set open so that people can add their own tag types
+     * to their custom parser and still communicate to the
+     * reader.
+     */
+    public static class Tag {
+
+        /** @since 1.3 */
+        public Tag() {}
+
+        /**
+         * Creates a new <code>Tag</code> with the specified <code>id</code>,
+         * and with <code>causesBreak</code> and <code>isBlock</code>
+         * set to <code>false</code>.
+         *
+         * @param id  the id of the new tag
+         */
+        protected Tag(String id) {
+            this(id, false, false);
+        }
+
+        /**
+         * Creates a new <code>Tag</code> with the specified <code>id</code>;
+         * <code>causesBreak</code> and <code>isBlock</code> are defined
+         * by the user.
+         *
+         * @param id the id of the new tag
+         * @param causesBreak  <code>true</code> if this tag
+         *    causes a break to the flow of data
+         * @param isBlock <code>true</code> if the tag is used
+         *    to add structure to a document
+         */
+        protected Tag(String id, boolean causesBreak, boolean isBlock) {
+            name = id;
+            this.breakTag = causesBreak;
+            this.blockTag = isBlock;
+        }
+
+        /**
+         * Returns <code>true</code> if this tag is a block
+         * tag, which is a tag used to add structure to a
+         * document.
+         *
+         * @return <code>true</code> if this tag is a block
+         *   tag, otherwise returns <code>false</code>
+         */
+        public boolean isBlock() {
+            return blockTag;
+        }
+
+        /**
+         * Returns <code>true</code> if this tag causes a
+         * line break to the flow of data, otherwise returns
+         * <code>false</code>.
+         *
+         * @return <code>true</code> if this tag causes a
+         *   line break to the flow of data, otherwise returns
+         *   <code>false</code>
+         */
+        public boolean breaksFlow() {
+            return breakTag;
+        }
+
+        /**
+         * Returns <code>true</code> if this tag is pre-formatted,
+         * which is true if the tag is either <code>PRE</code> or
+         * <code>TEXTAREA</code>.
+         *
+         * @return <code>true</code> if this tag is pre-formatted,
+         *   otherwise returns <code>false</code>
+         */
+        public boolean isPreformatted() {
+            return (this == PRE || this == TEXTAREA);
+        }
+
+        /**
+         * Returns the string representation of the
+         * tag.
+         *
+         * @return the <code>String</code> representation of the tag
+         */
+        public String toString() {
+            return name;
+        }
+
+        /**
+         * Returns <code>true</code> if this tag is considered to be a paragraph
+         * in the internal HTML model. <code>false</code> - otherwise.
+         *
+         * @return <code>true</code> if this tag is considered to be a paragraph
+         *         in the internal HTML model. <code>false</code> - otherwise.
+         * @see javax.swing.text.html.HTMLDocument#HTMLReader#ParagraphAction
+         */
+        boolean isParagraph() {
+            return (
+                this == P
+                   || this == IMPLIED
+                   || this == DT
+                   || this == H1
+                   || this == H2
+                   || this == H3
+                   || this == H4
+                   || this == H5
+                   || this == H6
+            );
+        }
+
+        boolean blockTag;
+        boolean breakTag;
+        String name;
+        boolean unknown;
+
+        // --- Tag Names -----------------------------------
+
+        public static final Tag A = new Tag("a");
+        public static final Tag ADDRESS = new Tag("address");
+        public static final Tag APPLET = new Tag("applet");
+        public static final Tag AREA = new Tag("area");
+        public static final Tag B = new Tag("b");
+        public static final Tag BASE = new Tag("base");
+        public static final Tag BASEFONT = new Tag("basefont");
+        public static final Tag BIG = new Tag("big");
+        public static final Tag BLOCKQUOTE = new Tag("blockquote", true, true);
+        public static final Tag BODY = new Tag("body", true, true);
+        public static final Tag BR = new Tag("br", true, false);
+        public static final Tag CAPTION = new Tag("caption");
+        public static final Tag CENTER = new Tag("center", true, false);
+        public static final Tag CITE = new Tag("cite");
+        public static final Tag CODE = new Tag("code");
+        public static final Tag DD = new Tag("dd", true, true);
+        public static final Tag DFN = new Tag("dfn");
+        public static final Tag DIR = new Tag("dir", true, true);
+        public static final Tag DIV = new Tag("div", true, true);
+        public static final Tag DL = new Tag("dl", true, true);
+        public static final Tag DT = new Tag("dt", true, true);
+        public static final Tag EM = new Tag("em");
+        public static final Tag FONT = new Tag("font");
+        public static final Tag FORM = new Tag("form", true, false);
+        public static final Tag FRAME = new Tag("frame");
+        public static final Tag FRAMESET = new Tag("frameset");
+        public static final Tag H1 = new Tag("h1", true, true);
+        public static final Tag H2 = new Tag("h2", true, true);
+        public static final Tag H3 = new Tag("h3", true, true);
+        public static final Tag H4 = new Tag("h4", true, true);
+        public static final Tag H5 = new Tag("h5", true, true);
+        public static final Tag H6 = new Tag("h6", true, true);
+        public static final Tag HEAD = new Tag("head", true, true);
+        public static final Tag HR = new Tag("hr", true, false);
+        public static final Tag HTML = new Tag("html", true, false);
+        public static final Tag I = new Tag("i");
+        public static final Tag IMG = new Tag("img");
+        public static final Tag INPUT = new Tag("input");
+        public static final Tag ISINDEX = new Tag("isindex", true, false);
+        public static final Tag KBD = new Tag("kbd");
+        public static final Tag LI = new Tag("li", true, true);
+        public static final Tag LINK = new Tag("link");
+        public static final Tag MAP = new Tag("map");
+        public static final Tag MENU = new Tag("menu", true, true);
+        public static final Tag META = new Tag("meta");
+        /*public*/ static final Tag NOBR = new Tag("nobr");
+        public static final Tag NOFRAMES = new Tag("noframes", true, true);
+        public static final Tag OBJECT = new Tag("object");
+        public static final Tag OL = new Tag("ol", true, true);
+        public static final Tag OPTION = new Tag("option");
+        public static final Tag P = new Tag("p", true, true);
+        public static final Tag PARAM = new Tag("param");
+        public static final Tag PRE = new Tag("pre", true, true);
+        public static final Tag SAMP = new Tag("samp");
+        public static final Tag SCRIPT = new Tag("script");
+        public static final Tag SELECT = new Tag("select");
+        public static final Tag SMALL = new Tag("small");
+        public static final Tag SPAN = new Tag("span");
+        public static final Tag STRIKE = new Tag("strike");
+        public static final Tag S = new Tag("s");
+        public static final Tag STRONG = new Tag("strong");
+        public static final Tag STYLE = new Tag("style");
+        public static final Tag SUB = new Tag("sub");
+        public static final Tag SUP = new Tag("sup");
+        public static final Tag TABLE = new Tag("table", false, true);
+        public static final Tag TD = new Tag("td", true, true);
+        public static final Tag TEXTAREA = new Tag("textarea");
+        public static final Tag TH = new Tag("th", true, true);
+        public static final Tag TITLE = new Tag("title", true, true);
+        public static final Tag TR = new Tag("tr", false, true);
+        public static final Tag TT = new Tag("tt");
+        public static final Tag U = new Tag("u");
+        public static final Tag UL = new Tag("ul", true, true);
+        public static final Tag VAR = new Tag("var");
+
+        /**
+         * All text content must be in a paragraph element.
+         * If a paragraph didn't exist when content was
+         * encountered, a paragraph is manufactured.
+         * <p>
+         * This is a tag synthesized by the HTML reader.
+         * Since elements are identified by their tag type,
+         * we create a some fake tag types to mark the elements
+         * that were manufactured.
+         */
+        public static final Tag IMPLIED = new Tag("p-implied");
+
+        /**
+         * All text content is labeled with this tag.
+         * <p>
+         * This is a tag synthesized by the HTML reader.
+         * Since elements are identified by their tag type,
+         * we create a some fake tag types to mark the elements
+         * that were manufactured.
+         */
+        public static final Tag CONTENT = new Tag("content");
+
+        /**
+         * All comments are labeled with this tag.
+         * <p>
+         * This is a tag synthesized by the HTML reader.
+         * Since elements are identified by their tag type,
+         * we create a some fake tag types to mark the elements
+         * that were manufactured.
+         */
+        public static final Tag COMMENT = new Tag("comment");
+
+        static final Tag allTags[]  = {
+            A, ADDRESS, APPLET, AREA, B, BASE, BASEFONT, BIG,
+            BLOCKQUOTE, BODY, BR, CAPTION, CENTER, CITE, CODE,
+            DD, DFN, DIR, DIV, DL, DT, EM, FONT, FORM, FRAME,
+            FRAMESET, H1, H2, H3, H4, H5, H6, HEAD, HR, HTML,
+            I, IMG, INPUT, ISINDEX, KBD, LI, LINK, MAP, MENU,
+            META, NOBR, NOFRAMES, OBJECT, OL, OPTION, P, PARAM,
+            PRE, SAMP, SCRIPT, SELECT, SMALL, SPAN, STRIKE, S,
+            STRONG, STYLE, SUB, SUP, TABLE, TD, TEXTAREA,
+            TH, TITLE, TR, TT, U, UL, VAR
+        };
+
+        static {
+            // Force HTMLs static initialize to be loaded.
+            getTag("html");
+        }
+    }
+
+    // There is no unique instance of UnknownTag, so we allow it to be
+    // Serializable.
+    public static class UnknownTag extends Tag implements Serializable {
+
+        /**
+         * Creates a new <code>UnknownTag</code> with the specified
+         * <code>id</code>.
+         * @param id the id of the new tag
+         */
+        public UnknownTag(String id) {
+            super(id);
+        }
+
+        /**
+         * Returns the hash code which corresponds to the string
+         * for this tag.
+         */
+        public int hashCode() {
+            return toString().hashCode();
+        }
+
+        /**
+         * Compares this object to the specifed object.
+         * The result is <code>true</code> if and only if the argument is not
+         * <code>null</code> and is an <code>UnknownTag</code> object
+         * with the same name.
+         *
+         * @param     obj   the object to compare this tag with
+         * @return    <code>true</code> if the objects are equal;
+         *            <code>false</code> otherwise
+         */
+        public boolean equals(Object obj) {
+            if (obj instanceof UnknownTag) {
+                return toString().equals(obj.toString());
+            }
+            return false;
+        }
+
+        private void writeObject(java.io.ObjectOutputStream s)
+                     throws IOException {
+            s.defaultWriteObject();
+            s.writeBoolean(blockTag);
+            s.writeBoolean(breakTag);
+            s.writeBoolean(unknown);
+            s.writeObject(name);
+        }
+
+        private void readObject(ObjectInputStream s)
+            throws ClassNotFoundException, IOException {
+            s.defaultReadObject();
+            blockTag = s.readBoolean();
+            breakTag = s.readBoolean();
+            unknown = s.readBoolean();
+            name = (String)s.readObject();
+        }
+    }
+
+    /**
+     * Typesafe enumeration representing an HTML
+     * attribute.
+     */
+    public static final class Attribute {
+
+        /**
+         * Creates a new <code>Attribute</code> with the specified
+         * <code>id</code>.
+         *
+         * @param id the id of the new <code>Attribute</code>
+         */
+        Attribute(String id) {
+            name = id;
+        }
+
+        /**
+         * Returns the string representation of this attribute.
+         * @return the string representation of this attribute
+         */
+        public String toString() {
+            return name;
+        }
+
+        private String name;
+
+        public static final Attribute SIZE = new Attribute("size");
+        public static final Attribute COLOR = new Attribute("color");
+        public static final Attribute CLEAR = new Attribute("clear");
+        public static final Attribute BACKGROUND = new Attribute("background");
+        public static final Attribute BGCOLOR = new Attribute("bgcolor");
+        public static final Attribute TEXT = new Attribute("text");
+        public static final Attribute LINK = new Attribute("link");
+        public static final Attribute VLINK = new Attribute("vlink");
+        public static final Attribute ALINK = new Attribute("alink");
+        public static final Attribute WIDTH = new Attribute("width");
+        public static final Attribute HEIGHT = new Attribute("height");
+        public static final Attribute ALIGN = new Attribute("align");
+        public static final Attribute NAME = new Attribute("name");
+        public static final Attribute HREF = new Attribute("href");
+        public static final Attribute REL = new Attribute("rel");
+        public static final Attribute REV = new Attribute("rev");
+        public static final Attribute TITLE = new Attribute("title");
+        public static final Attribute TARGET = new Attribute("target");
+        public static final Attribute SHAPE = new Attribute("shape");
+        public static final Attribute COORDS = new Attribute("coords");
+        public static final Attribute ISMAP = new Attribute("ismap");
+        public static final Attribute NOHREF = new Attribute("nohref");
+        public static final Attribute ALT = new Attribute("alt");
+        public static final Attribute ID = new Attribute("id");
+        public static final Attribute SRC = new Attribute("src");
+        public static final Attribute HSPACE = new Attribute("hspace");
+        public static final Attribute VSPACE = new Attribute("vspace");
+        public static final Attribute USEMAP = new Attribute("usemap");
+        public static final Attribute LOWSRC = new Attribute("lowsrc");
+        public static final Attribute CODEBASE = new Attribute("codebase");
+        public static final Attribute CODE = new Attribute("code");
+        public static final Attribute ARCHIVE = new Attribute("archive");
+        public static final Attribute VALUE = new Attribute("value");
+        public static final Attribute VALUETYPE = new Attribute("valuetype");
+        public static final Attribute TYPE = new Attribute("type");
+        public static final Attribute CLASS = new Attribute("class");
+        public static final Attribute STYLE = new Attribute("style");
+        public static final Attribute LANG = new Attribute("lang");
+        public static final Attribute FACE = new Attribute("face");
+        public static final Attribute DIR = new Attribute("dir");
+        public static final Attribute DECLARE = new Attribute("declare");
+        public static final Attribute CLASSID = new Attribute("classid");
+        public static final Attribute DATA = new Attribute("data");
+        public static final Attribute CODETYPE = new Attribute("codetype");
+        public static final Attribute STANDBY = new Attribute("standby");
+        public static final Attribute BORDER = new Attribute("border");
+        public static final Attribute SHAPES = new Attribute("shapes");
+        public static final Attribute NOSHADE = new Attribute("noshade");
+        public static final Attribute COMPACT = new Attribute("compact");
+        public static final Attribute START = new Attribute("start");
+        public static final Attribute ACTION = new Attribute("action");
+        public static final Attribute METHOD = new Attribute("method");
+        public static final Attribute ENCTYPE = new Attribute("enctype");
+        public static final Attribute CHECKED = new Attribute("checked");
+        public static final Attribute MAXLENGTH = new Attribute("maxlength");
+        public static final Attribute MULTIPLE = new Attribute("multiple");
+        public static final Attribute SELECTED = new Attribute("selected");
+        public static final Attribute ROWS = new Attribute("rows");
+        public static final Attribute COLS = new Attribute("cols");
+        public static final Attribute DUMMY = new Attribute("dummy");
+        public static final Attribute CELLSPACING = new Attribute("cellspacing");
+        public static final Attribute CELLPADDING = new Attribute("cellpadding");
+        public static final Attribute VALIGN = new Attribute("valign");
+        public static final Attribute HALIGN = new Attribute("halign");
+        public static final Attribute NOWRAP = new Attribute("nowrap");
+        public static final Attribute ROWSPAN = new Attribute("rowspan");
+        public static final Attribute COLSPAN = new Attribute("colspan");
+        public static final Attribute PROMPT = new Attribute("prompt");
+        public static final Attribute HTTPEQUIV = new Attribute("http-equiv");
+        public static final Attribute CONTENT = new Attribute("content");
+        public static final Attribute LANGUAGE = new Attribute("language");
+        public static final Attribute VERSION = new Attribute("version");
+        public static final Attribute N = new Attribute("n");
+        public static final Attribute FRAMEBORDER = new Attribute("frameborder");
+        public static final Attribute MARGINWIDTH = new Attribute("marginwidth");
+        public static final Attribute MARGINHEIGHT = new Attribute("marginheight");
+        public static final Attribute SCROLLING = new Attribute("scrolling");
+        public static final Attribute NORESIZE = new Attribute("noresize");
+        public static final Attribute ENDTAG = new Attribute("endtag");
+        public static final Attribute COMMENT = new Attribute("comment");
+        static final Attribute MEDIA = new Attribute("media");
+
+        static final Attribute allAttributes[] = {
+            FACE,
+            COMMENT,
+            SIZE,
+            COLOR,
+            CLEAR,
+            BACKGROUND,
+            BGCOLOR,
+            TEXT,
+            LINK,
+            VLINK,
+            ALINK,
+            WIDTH,
+            HEIGHT,
+            ALIGN,
+            NAME,
+            HREF,
+            REL,
+            REV,
+            TITLE,
+            TARGET,
+            SHAPE,
+            COORDS,
+            ISMAP,
+            NOHREF,
+            ALT,
+            ID,
+            SRC,
+            HSPACE,
+            VSPACE,
+            USEMAP,
+            LOWSRC,
+            CODEBASE,
+            CODE,
+            ARCHIVE,
+            VALUE,
+            VALUETYPE,
+            TYPE,
+            CLASS,
+            STYLE,
+            LANG,
+            DIR,
+            DECLARE,
+            CLASSID,
+            DATA,
+            CODETYPE,
+            STANDBY,
+            BORDER,
+            SHAPES,
+            NOSHADE,
+            COMPACT,
+            START,
+            ACTION,
+            METHOD,
+            ENCTYPE,
+            CHECKED,
+            MAXLENGTH,
+            MULTIPLE,
+            SELECTED,
+            ROWS,
+            COLS,
+            DUMMY,
+            CELLSPACING,
+            CELLPADDING,
+            VALIGN,
+            HALIGN,
+            NOWRAP,
+            ROWSPAN,
+            COLSPAN,
+            PROMPT,
+            HTTPEQUIV,
+            CONTENT,
+            LANGUAGE,
+            VERSION,
+            N,
+            FRAMEBORDER,
+            MARGINWIDTH,
+            MARGINHEIGHT,
+            SCROLLING,
+            NORESIZE,
+            MEDIA,
+            ENDTAG
+        };
+    }
+
+    // The secret to 73, is that, given that the Hashtable contents
+    // never change once the static initialization happens, the initial size
+    // that the hashtable grew to was determined, and then that very size
+    // is used.
+    //
+    private static final Hashtable tagHashtable = new Hashtable(73);
+
+    /** Maps from StyleConstant key to HTML.Tag. */
+    private static final Hashtable scMapping = new Hashtable(8);
+
+    static {
+
+        for (int i = 0; i < Tag.allTags.length; i++ ) {
+            tagHashtable.put(Tag.allTags[i].toString(), Tag.allTags[i]);
+            StyleContext.registerStaticAttributeKey(Tag.allTags[i]);
+        }
+        StyleContext.registerStaticAttributeKey(Tag.IMPLIED);
+        StyleContext.registerStaticAttributeKey(Tag.CONTENT);
+        StyleContext.registerStaticAttributeKey(Tag.COMMENT);
+        for (int i = 0; i < Attribute.allAttributes.length; i++) {
+            StyleContext.registerStaticAttributeKey(Attribute.
+                                                    allAttributes[i]);
+        }
+        StyleContext.registerStaticAttributeKey(HTML.NULL_ATTRIBUTE_VALUE);
+        scMapping.put(StyleConstants.Bold, Tag.B);
+        scMapping.put(StyleConstants.Italic, Tag.I);
+        scMapping.put(StyleConstants.Underline, Tag.U);
+        scMapping.put(StyleConstants.StrikeThrough, Tag.STRIKE);
+        scMapping.put(StyleConstants.Superscript, Tag.SUP);
+        scMapping.put(StyleConstants.Subscript, Tag.SUB);
+        scMapping.put(StyleConstants.FontFamily, Tag.FONT);
+        scMapping.put(StyleConstants.FontSize, Tag.FONT);
+    }
+
+    /**
+     * Returns the set of actual HTML tags that
+     * are recognized by the default HTML reader.
+     * This set does not include tags that are
+     * manufactured by the reader.
+     */
+    public static Tag[] getAllTags() {
+        Tag[] tags = new Tag[Tag.allTags.length];
+        System.arraycopy(Tag.allTags, 0, tags, 0, Tag.allTags.length);
+        return tags;
+    }
+
+    /**
+     * Fetches a tag constant for a well-known tag name (i.e. one of
+     * the tags in the set {A, ADDRESS, APPLET, AREA, B,
+     * BASE, BASEFONT, BIG,
+     * BLOCKQUOTE, BODY, BR, CAPTION, CENTER, CITE, CODE,
+     * DD, DFN, DIR, DIV, DL, DT, EM, FONT, FORM, FRAME,
+     * FRAMESET, H1, H2, H3, H4, H5, H6, HEAD, HR, HTML,
+     * I, IMG, INPUT, ISINDEX, KBD, LI, LINK, MAP, MENU,
+     * META, NOBR, NOFRAMES, OBJECT, OL, OPTION, P, PARAM,
+     * PRE, SAMP, SCRIPT, SELECT, SMALL, SPAN, STRIKE, S,
+     * STRONG, STYLE, SUB, SUP, TABLE, TD, TEXTAREA,
+     * TH, TITLE, TR, TT, U, UL, VAR}.  If the given
+     * name does not represent one of the well-known tags, then
+     * <code>null</code> will be returned.
+     *
+     * @param tagName the <code>String</code> name requested
+     * @return a tag constant corresponding to the <code>tagName</code>,
+     *    or <code>null</code> if not found
+     */
+    public static Tag getTag(String tagName) {
+
+        Object t =  tagHashtable.get(tagName);
+        return (t == null ? null : (Tag)t);
+    }
+
+    /**
+     * Returns the HTML <code>Tag</code> associated with the
+     * <code>StyleConstants</code> key <code>sc</code>.
+     * If no matching <code>Tag</code> is found, returns
+     * <code>null</code>.
+     *
+     * @param sc the <code>StyleConstants</code> key
+     * @return tag which corresponds to <code>sc</code>, or
+     *   <code>null</code> if not found
+     */
+    static Tag getTagForStyleConstantsKey(StyleConstants sc) {
+        return (Tag)scMapping.get(sc);
+    }
+
+    /**
+     * Fetches an integer attribute value.  Attribute values
+     * are stored as a string, and this is a convenience method
+     * to convert to an actual integer.
+     *
+     * @param attr the set of attributes to use to try to fetch a value
+     * @param key the key to use to fetch the value
+     * @param def the default value to use if the attribute isn't
+     *  defined or there is an error converting to an integer
+     */
+    public static int getIntegerAttributeValue(AttributeSet attr,
+                                               Attribute key, int def) {
+        int value = def;
+        String istr = (String) attr.getAttribute(key);
+        if (istr != null) {
+            try {
+                value = Integer.valueOf(istr).intValue();
+            } catch (NumberFormatException e) {
+                value = def;
+            }
+        }
+        return value;
+    }
+
+    //  This is used in cases where the value for the attribute has not
+    //  been specified.
+    //
+    public static final String NULL_ATTRIBUTE_VALUE = "#DEFAULT";
+
+    // size determined similar to size of tagHashtable
+    private static final Hashtable attHashtable = new Hashtable(77);
+
+    static {
+
+        for (int i = 0; i < Attribute.allAttributes.length; i++ ) {
+            attHashtable.put(Attribute.allAttributes[i].toString(), Attribute.allAttributes[i]);
+        }
+    }
+
+    /**
+     * Returns the set of HTML attributes recognized.
+     * @return the set of HTML attributes recognized
+     */
+    public static Attribute[] getAllAttributeKeys() {
+        Attribute[] attributes = new Attribute[Attribute.allAttributes.length];
+        System.arraycopy(Attribute.allAttributes, 0,
+                         attributes, 0, Attribute.allAttributes.length);
+        return attributes;
+    }
+
+    /**
+     * Fetches an attribute constant for a well-known attribute name
+     * (i.e. one of the attributes in the set {FACE, COMMENT, SIZE,
+     * COLOR, CLEAR, BACKGROUND, BGCOLOR, TEXT, LINK, VLINK, ALINK,
+     * WIDTH, HEIGHT, ALIGN, NAME, HREF, REL, REV, TITLE, TARGET,
+     * SHAPE, COORDS, ISMAP, NOHREF, ALT, ID, SRC, HSPACE, VSPACE,
+     * USEMAP, LOWSRC, CODEBASE, CODE, ARCHIVE, VALUE, VALUETYPE,
+     * TYPE, CLASS, STYLE, LANG, DIR, DECLARE, CLASSID, DATA, CODETYPE,
+     * STANDBY, BORDER, SHAPES, NOSHADE, COMPACT, START, ACTION, METHOD,
+     * ENCTYPE, CHECKED, MAXLENGTH, MULTIPLE, SELECTED, ROWS, COLS,
+     * DUMMY, CELLSPACING, CELLPADDING, VALIGN, HALIGN, NOWRAP, ROWSPAN,
+     * COLSPAN, PROMPT, HTTPEQUIV, CONTENT, LANGUAGE, VERSION, N,
+     * FRAMEBORDER, MARGINWIDTH, MARGINHEIGHT, SCROLLING, NORESIZE,
+     * MEDIA, ENDTAG}).
+     * If the given name does not represent one of the well-known attributes,
+     * then <code>null</code> will be returned.
+     *
+     * @param attName the <code>String</code> requested
+     * @return the <code>Attribute</code> corresponding to <code>attName</code>
+     */
+    public static Attribute getAttributeKey(String attName) {
+        Object a = attHashtable.get(attName);
+        if (a == null) {
+          return null;
+        }
+        return (Attribute)a;
+    }
+
+}