/*
 *  
 *
 * Copyright  1990-2006 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program 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. 
 * 
 * This program 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 at /legal/license.txt). 
 * 
 * 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 or visit www.sun.com if you need additional
 * information or have any questions. 
 */

// SAX locator interface for document events.

package org.xml.sax;

/**
 * Interface for associating a SAX event with a document location.
 *
 * <blockquote>
 * <em>This module, both source code and documentation, is in the
 * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
 * </blockquote>
 *
 * <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 content
 * handler's {@link org.xml.sax.helpers.DefaultHandler#setDocumentLocator
 * setDocumentLocator} method.  The application can use the
 * object to obtain the location of any other content handler event
 * in the XML source document.</p>
 *
 * <p>Note that the results returned by the object will be valid only
 * during the scope of each content handler method: the application
 * will receive unpredictable results if it attempts to use the
 * locator at any other time.</p>
 *
 * <p>SAX parsers are not required to supply a locator, but they are
 * very strongly 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>
 *
 * @since SAX 1.0
 *         
 * @version 2.0
 */
public interface Locator {
    
    
    /**
     * Return the public identifier for the current document event.
     *
     * <p>The return value is the public identifier of the document
     * entity or of the external parsed entity in which the markup
     * triggering the event appears.</p>
     *
     * @return A string containing the public identifier, or
     *         null if none is available.
     * @see #getSystemId
     */
    public abstract String getPublicId ();
    
    
    /**
     * Return the system identifier for the current document event.
     *
     * <p>The return value is the system identifier of the document
     * entity or of the external parsed entity in which the markup
     * triggering the event appears.</p>
     *
     * <p>If the system identifier is a URL, the parser must resolve it
     * fully before passing it to the application.</p>
     *
     * @return A string containing the system identifier, or null
     *         if none is available.
     * @see #getPublicId
     */
    public abstract String getSystemId ();
    
    
    /**
     * Return the line number where the current document event ends.
     *
     * <p><strong>Warning:</strong> The return value from the method
     * is intended only as an approximation for the sake of error
     * reporting; it is not intended to provide sufficient information
     * to edit the character content of the original XML document.</p>
     *
     * <p>The return value is an approximation of the line number
     * in the document entity or external parsed entity where the
     * markup triggering the event appears.</p>
     *
     * <p>If possible, the SAX driver should provide the line position 
     * of the first character after the text associated with the document 
     * event.  The first line in the document is line 1.</p>
     *
     * @return The line number, or -1 if none is available.
     * @see #getColumnNumber
     */
    public abstract int getLineNumber ();
    
    
    /**
     * Return the column number where the current document event ends.
     *
     * <p><strong>Warning:</strong> The return value from the method
     * is intended only as an approximation for the sake of error
     * reporting; it is not intended to provide sufficient information
     * to edit the character content of the original XML document.</p>
     *
     * <p>The return value is an approximation of the column number
     * in the document entity or external parsed entity where the
     * markup triggering the event appears.</p>
     *
     * <p>If possible, the SAX driver should provide the line position 
     * of the first character after the text associated with the document 
     * event.  The first column in each line is column 1.</p>
     *
     * @return The column number, or -1 if none is available.
     * @see #getLineNumber
     */
    public abstract int getColumnNumber ();
    
}

// end of Locator.java
