/*
 * Copyright (c) 1999 World Wide Web Consortium
 * (Massachusetts Institute of Technology, Institut National de Recherche
 *  en Informatique et en Automatique, Keio University).
 * All Rights Reserved. http://www.w3.org/Consortium/Legal/
 *
 * The original version of this interface comes from SAX :
 * http://www.megginson.com/SAX/
 *
 * $Id: Parser.java,v 1.2 2000/11/10 17:14:20 hillion Exp $
 */
package org.w3c.css.sac;

import java.io.IOException;
import java.util.Locale;

/**
 * Basic interface for CSS (Simple API for CSS) parsers.
 *
 * <p>All CSS parsers must implement this basic interface: it allows
 * applications to register handlers for different types of events
 * and to initiate a parse from a URI, or a character stream.</p>
 *
 * <p>All CSS parsers must also implement a zero-argument constructor
 * (though other constructors are also allowed).</p>
 *
 * <p>CSS parsers are reusable but not re-entrant: the application
 * may reuse a parser object (possibly with a different input source)
 * once the first parse has completed successfully, but it may not
 * invoke the parse() methods recursively within a parse.</p>
 *
 * @version $Revision: 1.2 $
 * @author  Philippe Le Hegaret
 * @see DocumentHandler
 * @see ErrorHandler
 * @see InputSource
 */
public interface Parser {
    
    /**
     * Allow an application to request a locale for errors and warnings.
     *
     * <p>CSS parsers are not required to provide localisation for errors
     * and warnings; if they cannot support the requested locale,
     * however, they must throw a CSS exception.  Applications may
     * not request a locale change in the middle of a parse.</p>
     *
     * @param locale A Java Locale object.
     * @exception CSSException Throws an exception
     *            (using the previous or default locale) if the 
     *            requested locale is not supported.
     * @see CSSException
     * @see CSSParseException
     */
    public void setLocale(Locale locale) throws CSSException;
    
    /**
     * Allow an application to register a document event handler.
     *
     * <p>If the application does not register a document handler, all
     * document events reported by the CSS parser will be silently
     * ignored (this is the default behaviour implemented by
     * HandlerBase).</p>
     *
     * <p>Applications may register a new or different handler in the
     * middle of a parse, and the CSS parser must begin using the new
     * handler immediately.</p>
     *
     * @param handler The document handler.
     * @see DocumentHandler
     */
    public void setDocumentHandler(DocumentHandler handler);

    public void setSelectorFactory(SelectorFactory selectorFactory);
    public void setConditionFactory(ConditionFactory conditionFactory);
    
    /**
     * Allow an application to register an error event handler.
     *
     * <p>If the application does not register an error event handler,
     * all error events reported by the CSS parser will be silently
     * ignored, except for fatalError, which will throw a CSSException
     * (this is the default behaviour implemented by HandlerBase).</p>
     *
     * <p>Applications may register a new or different handler in the
     * middle of a parse, and the CSS parser must begin using the new
     * handler immediately.</p>
     *
     * @param handler The error handler.
     * @see ErrorHandler
     * @see CSSException
     */
    public void setErrorHandler(ErrorHandler handler);
    
    /**
     * Parse a CSS document.
     *
     * <p>The application can use this method to instruct the CSS parser
     * to begin parsing an CSS document from any valid input
     * source (a character stream, a byte stream, or a URI).</p>
     *
     * <p>Applications may not invoke this method while a parse is in
     * progress (they should create a new Parser instead for each
     * additional CSS document).  Once a parse is complete, an
     * application may reuse the same Parser object, possibly with a
     * different input source.</p>
     *
     * @param source The input source for the top-level of the
     *        CSS document.
     * @exception CSSException Any CSS exception, possibly
     *            wrapping another exception.
     * @exception java.io.IOException An IO exception from the parser,
     *            possibly from a byte stream or character stream
     *            supplied by the application.
     * @see InputSource
     * @see #parseStyleSheet(java.lang.String)
     * @see #setDocumentHandler
     * @see #setErrorHandler
     */
    public void parseStyleSheet(InputSource source) 
	throws CSSException, IOException;
    
    
    /**
     * Parse a CSS document from a URI.
     *
     * <p>This method is a shortcut for the common case of reading a document
     * from a URI.  It is the exact equivalent of the following:</p>
     *
     * <pre>
     * parse(new InputSource(uri));
     * </pre>
     *
     * <p>The URI must be fully resolved by the application before it is passed
     * to the parser.</p>
     *
     * @param uri The URI.
     * @exception CSSException Any CSS exception, possibly
     *            wrapping another exception.
     * @exception java.io.IOException An IO exception from the parser,
     *            possibly from a byte stream or character stream
     *            supplied by the application.
     * @see #parseStyleSheet(InputSource) 
     */
    public void parseStyleSheet(String uri) throws CSSException, IOException;

    /**
     * Parse a CSS style declaration (without '{' and '}').
     *
     * @param styleValue The declaration.
     * @exception CSSException Any CSS exception, possibly
     *            wrapping another exception.
     * @exception java.io.IOException An IO exception from the parser,
     *            possibly from a byte stream or character stream
     *            supplied by the application.
     */
    public void parseStyleDeclaration(InputSource source) 
	throws CSSException, IOException;


    /**
     * Parse a CSS rule.
     *
     * @exception CSSException Any CSS exception, possibly
     *            wrapping another exception.
     * @exception java.io.IOException An IO exception from the parser,
     *            possibly from a byte stream or character stream
     *            supplied by the application.
     */
    public void parseRule(InputSource source) throws CSSException, IOException;

    /**
     * Returns a string about which CSS language is supported by this
     * parser. For CSS Level 1, it returns "CSS1", for CSS Level 2, it returns
     * "CSS2". For CSS Level 3, it returns "CSS3", etc. Note that a "CSSx"
     * parser can return lexical unit other than those allowed by CSS Level x
     * but this usage is not recommended.
     */
    public String getParserVersion();
    
    /**
     * Parse a comma separated list of selectors.
     * 
     * 
     * @exception CSSException Any CSS exception, possibly
     *            wrapping another exception.
     * @exception java.io.IOException An IO exception from the parser,
     *            possibly from a byte stream or character stream
     *            supplied by the application.
     */    
    public SelectorList parseSelectors(InputSource source)
        throws CSSException, IOException;


    /**
     * Parse a CSS property value.
     * 
     * 
     * @exception CSSException Any CSS exception, possibly
     *            wrapping another exception.
     * @exception java.io.IOException An IO exception from the parser,
     *            possibly from a byte stream or character stream
     *            supplied by the application.
     */    
    public LexicalUnit parsePropertyValue(InputSource source)
        throws CSSException, IOException;

    
    /**
     * Parse a CSS priority value (e.g. "!important").
     * 
     * 
     * @exception CSSException Any CSS exception, possibly
     *            wrapping another exception.
     * @exception java.io.IOException An IO exception from the parser,
     *            possibly from a byte stream or character stream
     *            supplied by the application.
     */    
    public boolean parsePriority(InputSource source)
        throws CSSException, IOException;
}
