/*

 ============================================================================
                   The Apache Software License, Version 1.1
 ============================================================================

 Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.

 Redistribution and use in source and binary forms, with or without modifica-
 tion, are permitted provided that the following conditions are met:

 1. Redistributions of  source code must  retain the above copyright  notice,
    this list of conditions and the following disclaimer.

 2. Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

 3. The end-user documentation included with the redistribution, if any, must
    include  the following  acknowledgment:  "This product includes  software
    developed  by the  Apache Software Foundation  (http://www.apache.org/)."
    Alternately, this  acknowledgment may  appear in the software itself,  if
    and wherever such third-party acknowledgments normally appear.

 4. The names "Batik" and  "Apache Software Foundation" must  not  be
    used to  endorse or promote  products derived from  this software without
    prior written permission. For written permission, please contact
    apache@apache.org.

 5. Products  derived from this software may not  be called "Apache", nor may
    "Apache" appear  in their name,  without prior written permission  of the
    Apache Software Foundation.

 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 FITNESS  FOR A PARTICULAR  PURPOSE ARE  DISCLAIMED.  IN NO  EVENT SHALL  THE
 APACHE SOFTWARE  FOUNDATION  OR ITS CONTRIBUTORS  BE LIABLE FOR  ANY DIRECT,
 INDIRECT, INCIDENTAL, SPECIAL,  EXEMPLARY, OR CONSEQUENTIAL  DAMAGES (INCLU-
 DING, BUT NOT LIMITED TO, PROCUREMENT  OF SUBSTITUTE GOODS OR SERVICES; LOSS
 OF USE, DATA, OR  PROFITS; OR BUSINESS  INTERRUPTION)  HOWEVER CAUSED AND ON
 ANY  THEORY OF LIABILITY,  WHETHER  IN CONTRACT,  STRICT LIABILITY,  OR TORT
 (INCLUDING  NEGLIGENCE OR  OTHERWISE) ARISING IN  ANY WAY OUT OF THE  USE OF
 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 This software  consists of voluntary contributions made  by many individuals
 on  behalf of the Apache Software  Foundation. For more  information on the
 Apache Software Foundation, please see <http://www.apache.org/>.

*/

package org.apache.batik.css.parser;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.StringTokenizer;

import org.apache.batik.i18n.Localizable;
import org.apache.batik.i18n.LocalizableSupport;
import org.apache.batik.util.CSSConstants;
import org.apache.batik.util.ParsedURL;
import org.w3c.css.sac.CSSException;
import org.w3c.css.sac.CSSParseException;
import org.w3c.css.sac.Condition;
import org.w3c.css.sac.ConditionFactory;
import org.w3c.css.sac.DocumentHandler;
import org.w3c.css.sac.ErrorHandler;
import org.w3c.css.sac.InputSource;
import org.w3c.css.sac.LexicalUnit;
import org.w3c.css.sac.SACMediaList;
import org.w3c.css.sac.Selector;
import org.w3c.css.sac.SelectorFactory;
import org.w3c.css.sac.SelectorList;
import org.w3c.css.sac.SimpleSelector;

/**
 * This class implements the {@link org.w3c.css.sac.Parser} interface.
 *
 * @author <a href="mailto:stephane@hillion.org">Stephane Hillion</a>
 * @version $Id: Parser.java,v 1.26 2003/12/18 01:36:39 deweese Exp $
 */
public class Parser implements ExtendedParser, Localizable {

    /**
     * The default resource bundle base name.
     */
    public final static String BUNDLE_CLASSNAME =
        "org.apache.batik.css.parser.resources.Messages";

    /**
     * The localizable support.
     */
    protected LocalizableSupport localizableSupport =
        new LocalizableSupport(BUNDLE_CLASSNAME, 
                               Parser.class.getClassLoader());

    /**
     * The scanner used to scan the input source.
     */
    protected Scanner scanner;

    /**
     * The current lexical unit.
     */
    protected int current;

    /**
     * The document handler.
     */
    protected DocumentHandler documentHandler =
        DefaultDocumentHandler.INSTANCE;

    /**
     * The selector factory.
     */
    protected SelectorFactory selectorFactory =
        DefaultSelectorFactory.INSTANCE;

    /**
     * The condition factory.
     */
    protected ConditionFactory conditionFactory =
        DefaultConditionFactory.INSTANCE;

    /**
     * The error handler.
     */
    protected ErrorHandler errorHandler = DefaultErrorHandler.INSTANCE;

    /**
     * To store the current pseudo element.
     */
    protected String pseudoElement;

    /**
     * The document URI.
     */
    protected String documentURI;

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#getParserVersion()}.
     * @return "http://www.w3.org/TR/REC-CSS2".
     */
    public String getParserVersion() {
        return "http://www.w3.org/TR/REC-CSS2";
    }
    
    /**
     * <b>SAC</b>: Implements {@link org.w3c.css.sac.Parser#setLocale(Locale)}.
     */
    public void setLocale(Locale locale) throws CSSException {
        localizableSupport.setLocale(locale);
    }
    
    /**
     * Implements {@link org.apache.batik.i18n.Localizable#getLocale()}.
     */
    public Locale getLocale() {
        return localizableSupport.getLocale();
    }

    /**
     * Implements {@link
     * org.apache.batik.i18n.Localizable#formatMessage(String,Object[])}.
     */
    public String formatMessage(String key, Object[] args)
        throws MissingResourceException {
        return localizableSupport.formatMessage(key, args);
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#setDocumentHandler(DocumentHandler)}.
     */
    public void setDocumentHandler(DocumentHandler handler) {
        documentHandler = handler;
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#setSelectorFactory(SelectorFactory)}.
     */
    public void setSelectorFactory(SelectorFactory factory) {
        selectorFactory = factory;
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#setConditionFactory(ConditionFactory)}.
     */
    public void setConditionFactory(ConditionFactory factory) {
        conditionFactory = factory;
    }
    
    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#setErrorHandler(ErrorHandler)}.
     */
    public void setErrorHandler(ErrorHandler handler) {
        errorHandler = handler;
    }
    
    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#parseStyleSheet(InputSource)}.
     */
    public void parseStyleSheet(InputSource source) 
        throws CSSException, IOException {
        scanner = createScanner(source);

        try {
            documentHandler.startDocument(source);

            current = scanner.next();
            switch (current) {
            case LexicalUnits.CHARSET_SYMBOL:
                if (nextIgnoreSpaces() != LexicalUnits.STRING) {
                    reportError("charset.string");
                } else {
                    if (nextIgnoreSpaces() != LexicalUnits.SEMI_COLON) {
                        reportError("semicolon");
                    }
                    next();
                }
                break;
            case LexicalUnits.COMMENT:
                documentHandler.comment(scanner.getStringValue());
            }

            skipSpacesAndCDOCDC();
            for (;;) {
                if (current == LexicalUnits.IMPORT_SYMBOL) {
                    nextIgnoreSpaces();
                    parseImportRule();
                    nextIgnoreSpaces();
                } else {
                    break;
                }
            }
            
            loop: for (;;) {
                switch (current) {
                case LexicalUnits.PAGE_SYMBOL:
                    nextIgnoreSpaces();
                    parsePageRule();
                    break;
                case LexicalUnits.MEDIA_SYMBOL:
                    nextIgnoreSpaces();
                    parseMediaRule();
                    break;
                case LexicalUnits.FONT_FACE_SYMBOL:
                    nextIgnoreSpaces();
                    parseFontFaceRule();
                    break;
                case LexicalUnits.AT_KEYWORD:
                    nextIgnoreSpaces();
                    parseAtRule();
                    break;
                case LexicalUnits.EOF:
                    break loop;
                default:
                    parseRuleSet();
                }
                skipSpacesAndCDOCDC();
            }
        } finally {
            documentHandler.endDocument(source);
            scanner = null;
        }
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#parseStyleSheet(String)}.
     */
    public void parseStyleSheet(String uri) throws CSSException, IOException {
        parseStyleSheet(new InputSource(uri));
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#parseStyleDeclaration(InputSource)}.
     */
    public void parseStyleDeclaration(InputSource source) 
        throws CSSException, IOException {

        scanner = createScanner(source);
	parseStyleDeclarationInternal();
    }

    /**
     * Parses a style declaration using the current scanner.
     */
    protected void parseStyleDeclarationInternal() 
	throws CSSException, IOException {
        nextIgnoreSpaces();
        try {
            parseStyleDeclaration(false);
        } catch (CSSParseException e) {
            reportError(e);
        } finally {
            scanner = null;
        }
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#parseRule(InputSource)}.
     */
    public void parseRule(InputSource source) 
	throws CSSException, IOException {
        scanner = createScanner(source);
	parseRuleInternal();
    }

    /**
     * Parses a rule using the current scanner.
     */
    protected void parseRuleInternal() throws CSSException, IOException {
        nextIgnoreSpaces();
        parseRule();
        scanner = null;
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.Parser#parseSelectors(InputSource)}.
     */    
    public SelectorList parseSelectors(InputSource source)
        throws CSSException, IOException {
        scanner = createScanner(source);
	return parseSelectorsInternal();
    }

    /**
     * Parses selectors using the current scanner.
     */
    protected SelectorList parseSelectorsInternal() 
	throws CSSException, IOException {
        nextIgnoreSpaces();
        SelectorList ret = parseSelectorList();
        scanner = null;
        return ret;
    }

    /**
     * <b>SAC</b>: Implements
     * {@link org.w3c.css.sac.Parser#parsePropertyValue(InputSource)}.
     */    
    public LexicalUnit parsePropertyValue(InputSource source)
        throws CSSException, IOException {
        scanner = createScanner(source);
	return parsePropertyValueInternal();
    }

    /**
     * Parses property value using the current scanner.
     */
    protected LexicalUnit parsePropertyValueInternal() 
	throws CSSException, IOException {
        nextIgnoreSpaces();
        
        LexicalUnit exp = null;

        try {
            exp = parseExpression(false);
        } catch (CSSParseException e) {
            reportError(e);
            throw e;
        }

        CSSParseException exception = null;
        if (current != LexicalUnits.EOF)
            exception = createCSSParseException("eof.expected");

        scanner = null;

        if (exception != null) {
            errorHandler.fatalError(exception);
        }
        return exp;
    }
    
    /**
     * <b>SAC</b>: Implements
     * {@link org.w3c.css.sac.Parser#parsePriority(InputSource)}.
     */    
    public boolean parsePriority(InputSource source)
        throws CSSException, IOException {
        scanner = createScanner(source);
	return parsePriorityInternal();
    }

    /**
     * Parses the priority using the current scanner.
     */
    protected boolean parsePriorityInternal()
        throws CSSException, IOException {
        nextIgnoreSpaces();

        scanner = null;

        switch (current) {
        case LexicalUnits.EOF:
            return false;
        case LexicalUnits.IMPORT_SYMBOL:
            return true;
        default:
            reportError("token", new Object[] { new Integer(current) });
            return false;
        }
    }

    /**
     * Parses a rule.
     */
    protected void parseRule() {
        switch (scanner.getType()) {
        case LexicalUnits.IMPORT_SYMBOL:
            nextIgnoreSpaces();
            parseImportRule();
            break;
        case LexicalUnits.AT_KEYWORD:
            nextIgnoreSpaces();
            parseAtRule();
            break;
        case LexicalUnits.FONT_FACE_SYMBOL:
            nextIgnoreSpaces();
            parseFontFaceRule();
            break;
        case LexicalUnits.MEDIA_SYMBOL:
            nextIgnoreSpaces();
            parseMediaRule();
            break;
        case LexicalUnits.PAGE_SYMBOL:
            nextIgnoreSpaces();
            parsePageRule();
            break;
        default:
            parseRuleSet();
        }
    }

    /**
     * Parses an unknown rule.
     */
    protected void parseAtRule() {
        scanner.scanAtRule();
        documentHandler.ignorableAtRule(scanner.getStringValue());
        nextIgnoreSpaces();
    }

    /**
     * Parses an import rule. Assumes the current token is '@import'.
     */
    protected void parseImportRule() {
        String uri = null;
        switch (current) {
        default:
            reportError("string.or.uri");
            return;
        case LexicalUnits.STRING:
        case LexicalUnits.URI:
            uri = scanner.getStringValue();
            nextIgnoreSpaces();
        }

        CSSSACMediaList ml;
        if (current != LexicalUnits.IDENTIFIER) {
            ml = new CSSSACMediaList();
            ml.append("all");
        } else {
            ml = parseMediaList();
        }

        documentHandler.importStyle(uri, ml, null);

        if (current != LexicalUnits.SEMI_COLON) {
            reportError("semicolon");
        } else {
            next();
        }
    }

    /**
     * Parses a media list.
     */
    protected CSSSACMediaList parseMediaList() {
        CSSSACMediaList result = new CSSSACMediaList();
        result.append(scanner.getStringValue());
        nextIgnoreSpaces();
        
        while (current == LexicalUnits.COMMA) {
            nextIgnoreSpaces();

            switch (current) {
            default:
                reportError("identifier");
                break;
            case LexicalUnits.IDENTIFIER:
                result.append(scanner.getStringValue());
                nextIgnoreSpaces();
            }
        }
        return result;
    }

    /**
     * Parses a font-face rule.
     */
    protected void parseFontFaceRule() {
        try {
            documentHandler.startFontFace();

            if (current != LexicalUnits.LEFT_CURLY_BRACE) {
                reportError("left.curly.brace");
            } else {
                nextIgnoreSpaces();
        
                try {
                    parseStyleDeclaration(true);
                } catch (CSSParseException e) {
                    reportError(e);
                }
            }
        } finally {
            documentHandler.endFontFace();
        }
    }

    /**
     * Parses a page rule.
     */
    protected void parsePageRule() {
        String page = null;
        String ppage = null;

        if (current == LexicalUnits.IDENTIFIER) {
            page = scanner.getStringValue();
            nextIgnoreSpaces();

            if (current == LexicalUnits.COLON) {
                nextIgnoreSpaces();

                if (current != LexicalUnits.IDENTIFIER) {
                    reportError("identifier");
                    return;
                }
                ppage = scanner.getStringValue();
                nextIgnoreSpaces();
            }
        }

        try {
            documentHandler.startPage(page, ppage);
            
            if (current != LexicalUnits.LEFT_CURLY_BRACE) {
                reportError("left.curly.brace");
            } else {
                nextIgnoreSpaces();
        
                try {
                    parseStyleDeclaration(true);
                } catch (CSSParseException e) {
                    reportError(e);
                }
            }
        } finally {
            documentHandler.endPage(page, ppage);
        }
    }
    
    /**
     * Parses a media rule.
     */
    protected void parseMediaRule() {
        if (current != LexicalUnits.IDENTIFIER) {
            reportError("identifier");
            return;
        }

        CSSSACMediaList ml = parseMediaList();
        try {
            documentHandler.startMedia(ml);

            if (current != LexicalUnits.LEFT_CURLY_BRACE) {
                reportError("left.curly.brace");
            } else {
                nextIgnoreSpaces();
            
                loop: for (;;) {
                    switch (current) {
                    case LexicalUnits.EOF:
                    case LexicalUnits.RIGHT_CURLY_BRACE:
                        break loop;
                    default:
                        parseRuleSet();
                    }
                }

                nextIgnoreSpaces();
            }
        } finally {
            documentHandler.endMedia(ml);
        }
    }

    /**
     * Parses a ruleset.
     */
    protected void parseRuleSet() {
        SelectorList sl = null;

        try {
            sl = parseSelectorList();
        } catch (CSSParseException e) {
            reportError(e);
            return;
        }

        try {
            documentHandler.startSelector(sl);

            if (current != LexicalUnits.LEFT_CURLY_BRACE) {
                reportError("left.curly.brace");
                if (current == LexicalUnits.RIGHT_CURLY_BRACE) {
                    nextIgnoreSpaces();
                }
            } else {
                nextIgnoreSpaces();
        
                try {
                    parseStyleDeclaration(true);
                } catch (CSSParseException e) {
                    reportError(e);
                }
            }
        } finally {
            documentHandler.endSelector(sl);
        }
    }

    /**
     * Parses a selector list
     */
    protected SelectorList parseSelectorList() {
        CSSSelectorList result = new CSSSelectorList();
        result.append(parseSelector());

        for (;;) {
            if (current != LexicalUnits.COMMA) {
                return result;
            }
            nextIgnoreSpaces();
            result.append(parseSelector());
        }
    }

    /**
     * Parses a selector.
     */
    protected Selector parseSelector() {
        SimpleSelector ss = parseSimpleSelector();
        Selector result = ss;

        pseudoElement = null;

        loop: for (;;) {
            switch (current) {
            default:
                break loop;
            case LexicalUnits.IDENTIFIER:
            case LexicalUnits.ANY:
            case LexicalUnits.HASH:
            case LexicalUnits.DOT:
            case LexicalUnits.LEFT_BRACKET:
            case LexicalUnits.COLON:
                result = selectorFactory.createDescendantSelector
                    (result,
                     parseSimpleSelector());
                break;
            case LexicalUnits.PLUS:
                nextIgnoreSpaces();
                result = selectorFactory.createDirectAdjacentSelector
                    ((short)1,
                     result, 
                     parseSimpleSelector());
                break;
            case LexicalUnits.PRECEDE:
                nextIgnoreSpaces();
                result = selectorFactory.createChildSelector
                    (result, 
                     parseSimpleSelector());
             }
        }
        if (pseudoElement != null) {
            result = selectorFactory.createChildSelector
                (result,
                 selectorFactory.createPseudoElementSelector
                 (null, pseudoElement));
        }
        return result;
    }

    /**
     * Parses a simple selector.
     */
    protected SimpleSelector parseSimpleSelector() {
        SimpleSelector result;

        switch (current) {
        case LexicalUnits.IDENTIFIER:
            result = selectorFactory.createElementSelector
                (null, scanner.getStringValue());
            next();
            break;
        case LexicalUnits.ANY:
            next();
        default:
            result = selectorFactory.createElementSelector(null, null);
        }
        Condition cond = null;
        loop: for (;;) {
            Condition c = null;
            switch (current) {
            case LexicalUnits.HASH:
                c = conditionFactory.createIdCondition
                    (scanner.getStringValue());
                next();
                break;
            case LexicalUnits.DOT:
                if (next() != LexicalUnits.IDENTIFIER) {
                    throw createCSSParseException("identifier");
                }
                c = conditionFactory.createClassCondition
                    (null, scanner.getStringValue());
                next();
                break;
            case LexicalUnits.LEFT_BRACKET:
                if (nextIgnoreSpaces() != LexicalUnits.IDENTIFIER) {
                    throw createCSSParseException("identifier");
                }
                String name = scanner.getStringValue();
                int op = nextIgnoreSpaces();
                switch (op) {
                default:
                    throw createCSSParseException("right.bracket");
                case LexicalUnits.RIGHT_BRACKET:
                    nextIgnoreSpaces();
                    c = conditionFactory.createAttributeCondition
                        (name, null, false, null);
                    break;
                case LexicalUnits.EQUAL:
                case LexicalUnits.INCLUDES:
                case LexicalUnits.DASHMATCH:
                    String val = null;
                    switch (nextIgnoreSpaces()) {
                    default:
                        throw createCSSParseException("identifier.or.string");
                    case LexicalUnits.STRING:
                    case LexicalUnits.IDENTIFIER:
                        val = scanner.getStringValue();
                        nextIgnoreSpaces();
                    }
                    if (current != LexicalUnits.RIGHT_BRACKET) {
                        throw createCSSParseException("right.bracket");
                    }
                    next();
                    switch (op) {
                    case LexicalUnits.EQUAL:
                        c = conditionFactory.createAttributeCondition
                            (name, null, false, val);
                        break;
                    case LexicalUnits.INCLUDES:
                        c = conditionFactory.createOneOfAttributeCondition
                            (name, null, false, val);
                        break;
                    default:
                        c = conditionFactory.
                            createBeginHyphenAttributeCondition
                            (name, null, false, val);
                    }
                }
                break;
            case LexicalUnits.COLON:
                switch (nextIgnoreSpaces()) {
                case LexicalUnits.IDENTIFIER:
                    String val = scanner.getStringValue();
                    if (isPseudoElement(val)) {
                        if (pseudoElement != null) {
                            throw createCSSParseException
                                ("duplicate.pseudo.element");
                        }
                        pseudoElement = val;
                    } else {
                        c = conditionFactory.createPseudoClassCondition
                            (null, val);
                    }
                    next();
                    break;
                case LexicalUnits.FUNCTION:
                    String func = scanner.getStringValue();
                    if (nextIgnoreSpaces() != LexicalUnits.IDENTIFIER) {
                        throw createCSSParseException("identifier");
                    }
                    String lang = scanner.getStringValue();
                    if (nextIgnoreSpaces() != LexicalUnits.RIGHT_BRACE) {
                        throw createCSSParseException("right.brace");
                    }

                    if (!func.equalsIgnoreCase("lang")) {
                        throw createCSSParseException("pseudo.function");
                    }

                    c = conditionFactory.createLangCondition(lang);

                    next();
                    break;
                default:
                    throw createCSSParseException("identifier");
                }
                break;
            default:
                break loop;
            }
            if (c != null) {
                if (cond == null) {
                    cond = c;
                } else {
                    cond = conditionFactory.createAndCondition(cond, c);
                }
            }
        }
        skipSpaces();
        if (cond != null) {
            result = selectorFactory.createConditionalSelector(result, cond);
        }
        return result;
    }

    /**
     * Tells whether or not the given string represents a pseudo-element.
     */
    protected boolean isPseudoElement(String s) {
        switch (s.charAt(0)) {
        case 'a':
        case 'A':
            return s.equalsIgnoreCase("after");
        case 'b':
        case 'B':
            return s.equalsIgnoreCase("before");
        case 'f':
        case 'F':
            return s.equalsIgnoreCase("first-letter") ||
                   s.equalsIgnoreCase("first-line");
        }
        return false;
    }

    /**
     * Parses the given reader.
     */
    protected void parseStyleDeclaration(boolean inSheet)
        throws CSSException {
        for (;;) {
            switch (current) {
            case LexicalUnits.EOF:
                if (inSheet) {
                    throw createCSSParseException("eof");
                }
                return;
            case LexicalUnits.RIGHT_CURLY_BRACE:
                if (!inSheet) {
                    throw createCSSParseException("eof.expected");
                }
                nextIgnoreSpaces();
                return;
            case LexicalUnits.SEMI_COLON:
                nextIgnoreSpaces();
                continue;
            default:
                throw createCSSParseException("identifier");
            case LexicalUnits.IDENTIFIER:
            }

            String name = scanner.getStringValue();
        
            if (nextIgnoreSpaces() != LexicalUnits.COLON) {
                throw createCSSParseException("colon");
            }
            nextIgnoreSpaces();
        
            LexicalUnit exp = null;
            
            try {
                exp = parseExpression(false);
            } catch (CSSParseException e) {
                reportError(e);
            }

            if (exp != null) {
                boolean important = false;
                if (current == LexicalUnits.IMPORTANT_SYMBOL) {
                    important = true;
                    nextIgnoreSpaces();
                }
                documentHandler.property(name, exp, important);
            }
        }
    }

    /**
     * Parses a CSS2 expression.
     * @param lex The type of the current lexical unit.
     */
    protected LexicalUnit parseExpression(boolean param) {
        LexicalUnit result = parseTerm(null);
        LexicalUnit curr = result;

        for (;;) {
            boolean op = false;
            switch (current) {
            case LexicalUnits.COMMA:
                op = true;
                curr = CSSLexicalUnit.createSimple
                    (LexicalUnit.SAC_OPERATOR_COMMA, curr);
                nextIgnoreSpaces();
                break;
            case LexicalUnits.DIVIDE:
                op = true;
                curr = CSSLexicalUnit.createSimple
                    (LexicalUnit.SAC_OPERATOR_SLASH, curr);
                nextIgnoreSpaces();
            }
            if (param) {
                if (current == LexicalUnits.RIGHT_BRACE) {
                    if (op) {
                        throw createCSSParseException
                            ("token", new Object[] { new Integer(current) });
                    }
                    return result;
                }
                curr = parseTerm(curr);
            } else {
                switch (current) {
                case LexicalUnits.IMPORTANT_SYMBOL:
                case LexicalUnits.SEMI_COLON:
                case LexicalUnits.RIGHT_CURLY_BRACE:
                case LexicalUnits.EOF:
                    if (op) {
                        throw createCSSParseException
                            ("token", new Object[] { new Integer(current) });
                    }
                    return result;
                default:
                    curr = parseTerm(curr);
                }
            }
        }
    }

    /**
     * Parses a CSS2 term.
     */
    protected LexicalUnit parseTerm(LexicalUnit prev) {
        boolean plus = true;
        boolean sgn = false;

        switch (current) {
        case LexicalUnits.MINUS:
            plus = false;
        case LexicalUnits.PLUS:
            next();
            sgn = true;
        default:
            switch (current) {
            case LexicalUnits.INTEGER:
                String sval = scanner.getStringValue();
                if (!plus) sval = "-"+sval;
                int val = Integer.parseInt(sval);
                nextIgnoreSpaces();
                return CSSLexicalUnit.createInteger(val, prev);
            case LexicalUnits.REAL:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_REAL,
                                                  number(plus), prev);
            case LexicalUnits.PERCENTAGE:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_PERCENTAGE,
                                                  number(plus), prev);
            case LexicalUnits.PT:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_POINT,
                                                  number(plus), prev);
            case LexicalUnits.PC:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_PICA,
                                                  number(plus), prev);
            case LexicalUnits.PX:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_PIXEL,
                                                  number(plus), prev);
            case LexicalUnits.CM:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_CENTIMETER,
                                                  number(plus), prev);
            case LexicalUnits.MM:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_MILLIMETER,
                                                  number(plus), prev);
            case LexicalUnits.IN:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_INCH,
                                                  number(plus), prev);
            case LexicalUnits.EM:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_EM,
                                                  number(plus), prev);
            case LexicalUnits.EX:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_EX,
                                                  number(plus), prev);
            case LexicalUnits.DEG:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_DEGREE,
                                                  number(plus), prev);
            case LexicalUnits.RAD:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_RADIAN,
                                                  number(plus), prev);
            case LexicalUnits.GRAD:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_GRADIAN,
                                                  number(plus), prev);
            case LexicalUnits.S:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_SECOND,
                                                  number(plus), prev);
            case LexicalUnits.MS:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_MILLISECOND,
                                                  number(plus), prev);
            case LexicalUnits.HZ:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_HERTZ,
                                                  number(plus), prev);
            case LexicalUnits.KHZ:
                return CSSLexicalUnit.createFloat(LexicalUnit.SAC_KILOHERTZ,
                                                  number(plus), prev);
            case LexicalUnits.DIMENSION:
                return dimension(plus, prev);
            case LexicalUnits.FUNCTION:
                return parseFunction(plus, prev);
            }
            if (sgn) {
                throw createCSSParseException
                    ("token",
                     new Object[] { new Integer(current) });
            }
        }
        switch (current) {
        case LexicalUnits.STRING:
            String val = scanner.getStringValue();
            nextIgnoreSpaces();
            return CSSLexicalUnit.createString(LexicalUnit.SAC_STRING_VALUE,
                                               val, prev);
        case LexicalUnits.IDENTIFIER:
            val = scanner.getStringValue();
            nextIgnoreSpaces();
            if (val.equalsIgnoreCase("inherit")) {
                return CSSLexicalUnit.createSimple(LexicalUnit.SAC_INHERIT,
                                                   prev);
            } else {
                return CSSLexicalUnit.createString(LexicalUnit.SAC_IDENT,
                                                   val, prev);
            }
        case LexicalUnits.URI:
            val = scanner.getStringValue();
            nextIgnoreSpaces();
            return CSSLexicalUnit.createString(LexicalUnit.SAC_URI,
                                               val, prev);
        case LexicalUnits.HASH:
            return hexcolor(prev);
        default:
            throw createCSSParseException
                ("token",
                 new Object[] { new Integer(current) });
        }
    }

    /**
     * Parses a CSS2 function.
     */
    protected LexicalUnit parseFunction(boolean positive, LexicalUnit prev) {
        String name = scanner.getStringValue();
        nextIgnoreSpaces();
        
        LexicalUnit params = parseExpression(true);

        if (current != LexicalUnits.RIGHT_BRACE) {
            throw createCSSParseException
                ("token",
                 new Object[] { new Integer(current) });
        }
        nextIgnoreSpaces();

        predefined: switch (name.charAt(0)) {
        case 'r':
        case 'R':
            LexicalUnit lu;
            if (name.equalsIgnoreCase("rgb")) {
                lu = params;
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_INTEGER:
                case LexicalUnit.SAC_PERCENTAGE:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_OPERATOR_COMMA:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_INTEGER:
                case LexicalUnit.SAC_PERCENTAGE:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_OPERATOR_COMMA:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_INTEGER:
                case LexicalUnit.SAC_PERCENTAGE:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu != null) {
                    break;
                }
                return CSSLexicalUnit.createPredefinedFunction
                    (LexicalUnit.SAC_RGBCOLOR, params, prev);
            } else if (name.equalsIgnoreCase("rect")) {
                lu = params;
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_INTEGER:
                    if (lu.getIntegerValue() != 0) {
                        break predefined;
                    }
                    lu = lu.getNextLexicalUnit();
                    break;
                case LexicalUnit.SAC_IDENT:
                    if (!lu.getStringValue().equalsIgnoreCase("auto")) {
                        break predefined;
                    }
                    lu = lu.getNextLexicalUnit();
                    break;
                case LexicalUnit.SAC_EM:
                case LexicalUnit.SAC_EX:
                case LexicalUnit.SAC_PIXEL:
                case LexicalUnit.SAC_CENTIMETER:
                case LexicalUnit.SAC_MILLIMETER:
                case LexicalUnit.SAC_INCH:
                case LexicalUnit.SAC_POINT:
                case LexicalUnit.SAC_PICA:
                case LexicalUnit.SAC_PERCENTAGE:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_OPERATOR_COMMA:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_INTEGER:
                    if (lu.getIntegerValue() != 0) {
                        break predefined;
                    }
                    lu = lu.getNextLexicalUnit();
                    break;
                case LexicalUnit.SAC_IDENT:
                    if (!lu.getStringValue().equalsIgnoreCase("auto")) {
                        break predefined;
                    }
                    lu = lu.getNextLexicalUnit();
                    break;
                case LexicalUnit.SAC_EM:
                case LexicalUnit.SAC_EX:
                case LexicalUnit.SAC_PIXEL:
                case LexicalUnit.SAC_CENTIMETER:
                case LexicalUnit.SAC_MILLIMETER:
                case LexicalUnit.SAC_INCH:
                case LexicalUnit.SAC_POINT:
                case LexicalUnit.SAC_PICA:
                case LexicalUnit.SAC_PERCENTAGE:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_OPERATOR_COMMA:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_INTEGER:
                    if (lu.getIntegerValue() != 0) {
                        break predefined;
                    }
                    lu = lu.getNextLexicalUnit();
                    break;
                case LexicalUnit.SAC_IDENT:
                    if (!lu.getStringValue().equalsIgnoreCase("auto")) {
                        break predefined;
                    }
                    lu = lu.getNextLexicalUnit();
                    break;
                case LexicalUnit.SAC_EM:
                case LexicalUnit.SAC_EX:
                case LexicalUnit.SAC_PIXEL:
                case LexicalUnit.SAC_CENTIMETER:
                case LexicalUnit.SAC_MILLIMETER:
                case LexicalUnit.SAC_INCH:
                case LexicalUnit.SAC_POINT:
                case LexicalUnit.SAC_PICA:
                case LexicalUnit.SAC_PERCENTAGE:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_OPERATOR_COMMA:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_INTEGER:
                    if (lu.getIntegerValue() != 0) {
                        break predefined;
                    }
                    lu = lu.getNextLexicalUnit();
                    break;
                case LexicalUnit.SAC_IDENT:
                    if (!lu.getStringValue().equalsIgnoreCase("auto")) {
                        break predefined;
                    }
                    lu = lu.getNextLexicalUnit();
                    break;
                case LexicalUnit.SAC_EM:
                case LexicalUnit.SAC_EX:
                case LexicalUnit.SAC_PIXEL:
                case LexicalUnit.SAC_CENTIMETER:
                case LexicalUnit.SAC_MILLIMETER:
                case LexicalUnit.SAC_INCH:
                case LexicalUnit.SAC_POINT:
                case LexicalUnit.SAC_PICA:
                case LexicalUnit.SAC_PERCENTAGE:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu != null) {
                    break;
                }
                return CSSLexicalUnit.createPredefinedFunction
                    (LexicalUnit.SAC_RECT_FUNCTION, params, prev);
            }
            break;
        case 'c':
        case 'C':
            if (name.equalsIgnoreCase("counter")) {
                lu = params;
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_IDENT:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_OPERATOR_COMMA:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_IDENT:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu != null) {
                    break;
                }
                return CSSLexicalUnit.createPredefinedFunction
                    (LexicalUnit.SAC_COUNTER_FUNCTION, params, prev);
            } else if (name.equalsIgnoreCase("counters")) {
                lu = params;
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_IDENT:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_OPERATOR_COMMA:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_STRING_VALUE:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_OPERATOR_COMMA:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_IDENT:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu != null) {
                    break;
                }
                return CSSLexicalUnit.createPredefinedFunction
                    (LexicalUnit.SAC_COUNTERS_FUNCTION, params, prev);
            }
            break;
        case 'a':
        case 'A':
            if (name.equalsIgnoreCase("attr")) {
                lu = params;
                if (lu == null) {
                    break;
                }
                switch (lu.getLexicalUnitType()) {
                default:
                    break predefined;
                case LexicalUnit.SAC_IDENT:
                    lu = lu.getNextLexicalUnit();
                }
                if (lu != null) {
                    break;
                }
                return CSSLexicalUnit.createString
                    (LexicalUnit.SAC_ATTR, params.getStringValue(), prev);
            }
        }

        return CSSLexicalUnit.createFunction(name, params, prev);
    }

    /**
     * Converts a hash unit to a RGB color.
     */
    protected LexicalUnit hexcolor(LexicalUnit prev) {
        String val = scanner.getStringValue();
        int len = val.length();
        LexicalUnit params = null;
        switch (len) {
        case 3:
            char rc = Character.toLowerCase(val.charAt(0));
            char gc = Character.toLowerCase(val.charAt(1));
            char bc = Character.toLowerCase(val.charAt(2));
            if (!ScannerUtilities.isCSSHexadecimalCharacter(rc) ||
                !ScannerUtilities.isCSSHexadecimalCharacter(gc) ||
                !ScannerUtilities.isCSSHexadecimalCharacter(bc)) {
                throw createCSSParseException
                    ("rgb.color", new Object[] { val });
            }
            int t;
            int r = t = (rc >= '0' && rc <= '9') ? rc - '0' : rc - 'a' + 10;
            t <<= 4;
            r |= t;
            int g = t = (gc >= '0' && gc <= '9') ? gc - '0' : gc - 'a' + 10;
            t <<= 4;
            g |= t;
            int b = t = (bc >= '0' && bc <= '9') ? bc - '0' : bc - 'a' + 10;
            t <<= 4;
            b |= t;
            params = CSSLexicalUnit.createInteger(r, null);
            LexicalUnit tmp;
            tmp = CSSLexicalUnit.createSimple
                (LexicalUnit.SAC_OPERATOR_COMMA, params);
            tmp = CSSLexicalUnit.createInteger(g, tmp);
            tmp = CSSLexicalUnit.createSimple
                (LexicalUnit.SAC_OPERATOR_COMMA, tmp);
            tmp = CSSLexicalUnit.createInteger(b, tmp);
            break;
        case 6:
            char rc1 = Character.toLowerCase(val.charAt(0));
            char rc2 = Character.toLowerCase(val.charAt(1));
            char gc1 = Character.toLowerCase(val.charAt(2));
            char gc2 = Character.toLowerCase(val.charAt(3));
            char bc1 = Character.toLowerCase(val.charAt(4));
            char bc2 = Character.toLowerCase(val.charAt(5));
            if (!ScannerUtilities.isCSSHexadecimalCharacter(rc1) ||
                !ScannerUtilities.isCSSHexadecimalCharacter(rc2) ||
                !ScannerUtilities.isCSSHexadecimalCharacter(gc1) ||
                !ScannerUtilities.isCSSHexadecimalCharacter(gc2) ||
                !ScannerUtilities.isCSSHexadecimalCharacter(bc1) ||
                !ScannerUtilities.isCSSHexadecimalCharacter(bc2)) {
                throw createCSSParseException("rgb.color");
            }
            r = (rc1 >= '0' && rc1 <= '9') ? rc1 - '0' : rc1 - 'a' + 10;
            r <<= 4;
            r |= (rc2 >= '0' && rc2 <= '9') ? rc2 - '0' : rc2 - 'a' + 10;
            g = (gc1 >= '0' && gc1 <= '9') ? gc1 - '0' : gc1 - 'a' + 10;
            g <<= 4;
            g |= (gc2 >= '0' && gc2 <= '9') ? gc2 - '0' : gc2 - 'a' + 10;
            b = (bc1 >= '0' && bc1 <= '9') ? bc1 - '0' : bc1 - 'a' + 10;
            b <<= 4;
            b |= (bc2 >= '0' && bc2 <= '9') ? bc2 - '0' : bc2 - 'a' + 10;
            params = CSSLexicalUnit.createInteger(r, null);
            tmp = CSSLexicalUnit.createSimple
                (LexicalUnit.SAC_OPERATOR_COMMA, params);
            tmp = CSSLexicalUnit.createInteger(g, tmp);
            tmp = CSSLexicalUnit.createSimple
                (LexicalUnit.SAC_OPERATOR_COMMA, tmp);
            tmp = CSSLexicalUnit.createInteger(b, tmp);
            break;
        default:
            throw createCSSParseException("rgb.color", new Object[] { val });
        }
        nextIgnoreSpaces();
        return CSSLexicalUnit.createPredefinedFunction
            (LexicalUnit.SAC_RGBCOLOR, params, prev);
    }

    /**
     * Creates a scanner, given an InputSource.
     */
    protected Scanner createScanner(InputSource source) {
        documentURI = source.getURI();
        if (documentURI == null) {
            documentURI = "";
        }

        Reader r = source.getCharacterStream();
        if (r != null) {
            return new Scanner(r);
        }

        InputStream is = source.getByteStream();
        if (is != null) {
            return new Scanner(is, source.getEncoding());
        }

        String uri = source.getURI();
        if (uri == null) {
            throw new CSSException(formatMessage("empty.source", null));
        }

        try {
            ParsedURL purl = new ParsedURL(uri);
            is = purl.openStreamRaw(CSSConstants.CSS_MIME_TYPE);
            return new Scanner(is, source.getEncoding());
        } catch (IOException e) {
            throw new CSSException(e);
        }
    }

    /**
     * Skips the white spaces.
     */
    protected int skipSpaces() {
        int lex = scanner.getType();
        while (lex == LexicalUnits.SPACE) {
            lex = next();
        }
        return lex;
    }

    /**
     * Skips the white spaces and CDO/CDC units.
     */
    protected int skipSpacesAndCDOCDC() {
        loop: for (;;) {
            switch (current) {
            default:
                break loop;
            case LexicalUnits.COMMENT:
            case LexicalUnits.SPACE:
            case LexicalUnits.CDO:
            case LexicalUnits.CDC:
            }
            scanner.clearBuffer();
            next();
        }
        return current;
    }

    /**
     * Converts the current lexical unit to a float.
     */
    protected float number(boolean positive) {
        try {
            float sgn = (positive) ? 1 : -1;
            String val = scanner.getStringValue();
            nextIgnoreSpaces();
            return sgn * Float.parseFloat(val);
        } catch (NumberFormatException e) {
            throw createCSSParseException("number.format");
        }
    }

    /**
     * Converts the current lexical unit to a dimension.
     */
    protected LexicalUnit dimension(boolean positive, LexicalUnit prev) {
        try {
            float sgn = (positive) ? 1 : -1;
            String val = scanner.getStringValue();
            int i;
            loop: for (i = 0; i < val.length(); i++) {
                switch (val.charAt(i)) {
                default:
                    break loop;
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                case '.':
                }
            }
            nextIgnoreSpaces();
            return CSSLexicalUnit.createDimension
                (sgn * Float.parseFloat(val.substring(0, i)),
                 val.substring(i),
                 prev);
        } catch (NumberFormatException e) {
            throw createCSSParseException("number.format");
        }
    }

    /**
     * Advances to the next token, ignoring comments.
     */
    protected int next() {
        try {
            for (;;) {
                scanner.clearBuffer();
                current = scanner.next();
                if (current == LexicalUnits.COMMENT) {
                    documentHandler.comment(scanner.getStringValue());
                } else {
                    break;
                }
            }
            return current;
        } catch (ParseException e) {
            reportError(e.getMessage());
            return current;
        }
    }

    /**
     * Advances to the next token and skip the spaces, ignoring comments.
     */
    protected int nextIgnoreSpaces() {
        try {
            loop: for (;;) {
                scanner.clearBuffer();
                current = scanner.next();
                switch (current) {
                case LexicalUnits.COMMENT:
                    documentHandler.comment(scanner.getStringValue());
                    break;
                default:
                    break loop;
                case LexicalUnits.SPACE:
                }
            }
            return current;
        } catch (ParseException e) {
            errorHandler.error(createCSSParseException(e.getMessage()));
            return current;
        }
    }

    /**
     * Reports a parsing error.
     */
    protected void reportError(String key) {
        reportError(key, null);
    }

    /**
     * Reports a parsing error.
     */
    protected void reportError(String key, Object[] params) {
        reportError(createCSSParseException(key, params));
    }

    /**
     * Reports a parsing error.
     */
    protected void reportError(CSSParseException e) {
        errorHandler.error(e);

        int cbraces = 1;
        for (;;) {
            switch (current) {
            case LexicalUnits.EOF:
                return;
            case LexicalUnits.SEMI_COLON:
            case LexicalUnits.RIGHT_CURLY_BRACE:
                if (--cbraces == 0) {
                    nextIgnoreSpaces();
                    return;
                }
            case LexicalUnits.LEFT_CURLY_BRACE:
                cbraces++;
            }
            nextIgnoreSpaces();
        }
    }

    /**
     * Creates a parse exception.
     */
    protected CSSParseException createCSSParseException(String key) {
        return createCSSParseException(key, null);
    }

    /**
     * Creates a parse exception.
     */
    protected CSSParseException createCSSParseException(String key,
                                                        Object[] params) {
        return new CSSParseException(formatMessage(key, params),
                                     documentURI,
                                     scanner.getLine(),
                                     scanner.getColumn());
    }

    // -----------------------------------------------------------------------
    // Extended methods
    // -----------------------------------------------------------------------
    
    /**
     * Implements {@link ExtendedParser#parseStyleDeclaration(String)}.
     */
    public void parseStyleDeclaration(String source) 
	throws CSSException, IOException {
        scanner = new Scanner(source);
	parseStyleDeclarationInternal();
    }

    /**
     * Implements {@link ExtendedParser#parseRule(String)}.
     */
    public void parseRule(String source) throws CSSException, IOException {
        scanner = new Scanner(source);
	parseRuleInternal();
    }
    
    /**
     * Implements {@link ExtendedParser#parseSelectors(String)}.
     */
    public SelectorList parseSelectors(String source)
        throws CSSException, IOException {
        scanner = new Scanner(source);
	return parseSelectorsInternal();
    }

    /**
     * Implements {@link ExtendedParser#parsePropertyValue(String)}.
     */
    public LexicalUnit parsePropertyValue(String source)
        throws CSSException, IOException {
        scanner = new Scanner(source);
	return parsePropertyValueInternal();
    }

    /**
     * Implements {@link ExtendedParser#parsePriority(String)}.
     */
    public boolean parsePriority(String source)
        throws CSSException, IOException {
        scanner = new Scanner(source);
	return parsePriorityInternal();
    }

    /**
     * Implements {@link ExtendedParser#parseMedia(String)}.
     */
    public SACMediaList parseMedia(String mediaText)
        throws CSSException, IOException {
        CSSSACMediaList result = new CSSSACMediaList();
        if (!"all".equalsIgnoreCase(mediaText)) {
            StringTokenizer st = new StringTokenizer(mediaText, " ,");
            while (st.hasMoreTokens()) {
                result.append(st.nextToken());
            }
        }
        return result;
    }
}
