http://xml.apache.org/commons/components/external/: xml-commons provides an Apache-hosted set of DOM, SAX, and JAXP interfaces for use in other xml-based projects. Our hope is that we can standardize on both a common version and packaging scheme for these critical XML standards interfaces to make the lives of both our developers and users easier. The External Components portion of xml-commons contains interfaces that are defined by external standards organizations. For DOM, that's the W3C; for SAX it's David Megginson and sax.sourceforge.net; for JAXP it's Sun. 
/*
 * 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: Locator.java 477010 2006-11-20 02:54:38Z mrglavas $
 */
package org.w3c.css.sac;


Interface for associating a CSS event with a document location.

If a SAX parser provides location information to the SAX
application, it does so by implementing this interface and then
passing an instance to the application using the document
handler's setDocumentLocator method.  The application can use the
object to obtain the location of any other document handler event
in the CSS source document.


Note that the results returned by the object will be valid only
during the scope of each document handler method: the application
will receive unpredictable results if it attempts to use the
locator at any other time.


CSS parsers are not required to supply a locator, but they are
very strong encouraged to do so.  If the parser supplies a
locator, it must do so before reporting any other document events.
If no locator has been set by the time the application receives
the startDocument event, the application should assume that a
locator is not available.


Author: Philippe Le Hegaret
Version:$Revision: 477010 $
/**
 * Interface for associating a CSS event with a document location.
 *
 * <p>If a SAX parser provides location information to the SAX
 * application, it does so by implementing this interface and then
 * passing an instance to the application using the document
 * handler's setDocumentLocator method.  The application can use the
 * object to obtain the location of any other document handler event
 * in the CSS source document.</p>
 *
 * <p>Note that the results returned by the object will be valid only
 * during the scope of each document handler method: the application
 * will receive unpredictable results if it attempts to use the
 * locator at any other time.</p>
 *
 * <p>CSS parsers are not required to supply a locator, but they are
 * very strong encouraged to do so.  If the parser supplies a
 * locator, it must do so before reporting any other document events.
 * If no locator has been set by the time the application receives
 * the startDocument event, the application should assume that a
 * locator is not available.</p>
 *
 * @version $Revision: 477010 $
 * @author  Philippe Le Hegaret
 */
public interface Locator {
    
    
Return the URI for the current document event.

The parser must resolve the URI fully before passing it to the
application.


Returns:A string containing the URI, or null
        if none is available.
/**
     * Return the URI for the current document event.
     *
     * <p>The parser must resolve the URI fully before passing it to the
     * application.</p>
     *
     * @return A string containing the URI, or null
     *         if none is available.
     */
    public String getURI();
    
    
Return the line number where the current document event ends.
Note that this is the line position of the first character
after the text associated with the document event.

See Also:
Returns:The line number, or -1 if none is available.
/**
     * Return the line number where the current document event ends.
     * Note that this is the line position of the first character
     * after the text associated with the document event.
     * @return The line number, or -1 if none is available.
     * @see #getColumnNumber
     */
    public int getLineNumber();
    
    
Return the column number where the current document event ends.
Note that this is the column number of the first
character after the text associated with the document
event.  The first column in a line is position 1.

See Also:
Returns:The column number, or -1 if none is available.
/**
     * Return the column number where the current document event ends.
     * Note that this is the column number of the first
     * character after the text associated with the document
     * event.  The first column in a line is position 1.
     * @return The column number, or -1 if none is available.
     * @see #getLineNumber
     */
    public int getColumnNumber();
}