Locator.java

/*
 * Copyright (c) 2000, 2005, Oracle and/or its affiliates. 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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// SAX locator interface for document events.
// http://www.saxproject.org
// No warranty; no copyright -- use this as you will.
// $Id: Locator.java,v 1.2 2004/11/03 22:55:32 jsuttor Exp $

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>
 * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
 * for further information.
 * </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.ContentHandler#setDocumentLocator
 * setDocumentLocator} method.  The application can use the
 * object to obtain the location of any other SAX 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 callback method: the application
 * will receive unpredictable results if it attempts to use the
 * locator at any other time, or after parsing completes.</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 {@link org.xml.sax.ContentHandler#startDocument startDocument}
 * event, the application should assume that a locator is not
 * available.</p>
 *
 * @since SAX 1.0
 * @author David Megginson
 * @see org.xml.sax.ContentHandler#setDocumentLocator
 */
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.  For example, a file
     * name must always be provided as a <em>file:...</em> URL, and other
     * kinds of relative URI are also resolved against their bases.</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.
     * Lines are delimited by line ends, which are defined in
     * the XML specification.
     *
     * <p><strong>Warning:</strong> The return value from the method
     * is intended only as an approximation for the sake of diagnostics;
     * it is not intended to provide sufficient information
     * to edit the character content of the original XML document.
     * In some cases, these "line" numbers match what would be displayed
     * as columns, and in others they may not match the source text
     * due to internal entity expansion.  </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 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.
     * This is one-based number of Java <code>char</code> values since
     * the last line end.
     *
     * <p><strong>Warning:</strong> The return value from the method
     * is intended only as an approximation for the sake of diagnostics;
     * it is not intended to provide sufficient information
     * to edit the character content of the original XML document.
     * For example, when lines contain combining character sequences, wide
     * characters, surrogate pairs, or bi-directional text, the value may
     * not correspond to the column in a text editor's display. </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