001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors.
006 *
007 * Project Info:  http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
022 * USA.
023 *
024 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025 * Other names may be trademarks of their respective owners.]
026 *
027 * -------------------------
028 * XYItemLabelGenerator.java
029 * -------------------------
030 * (C) Copyright 2001-2008, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes
036 * -------
037 * 13-Dec-2001 : Version 1 (DG);
038 * 16-Jan-2002 : Completed Javadocs (DG);
039 * 13-Jun-2002 : Correction to Javadoc comments (DG);
040 * 26-Sep-2002 : Fixed errors reported by Checkstyle (DG);
041 * 25-Feb-2004 : Renamed XYToolTipGenerator --> XYItemLabelGenerator (DG);
042 * 15-Apr-2004 : Moved the generateToolTip() method to a separate
043 *               interface (DG);
044 * 11-May-2004 : Renamed XYItemLabelGenerator --> XYLabelGenerator (DG);
045 * 20-Apr-2005 : Reverted name change of 11-May-2004 (DG);
046 *
047 */
048
049package org.jfree.chart.labels;
050
051import org.jfree.data.xy.XYDataset;
052
053/**
054 * Interface for a label generator for plots that use data from an
055 * {@link XYDataset}.
056 */
057public interface XYItemLabelGenerator {
058
059    /**
060     * Generates a label for the specified item. The label is typically a
061     * formatted version of the data value, but any text can be used.
062     *
063     * @param dataset  the dataset (<code>null</code> not permitted).
064     * @param series  the series index (zero-based).
065     * @param item  the item index (zero-based).
066     *
067     * @return The label (possibly <code>null</code>).
068     */
069    public String generateLabel(XYDataset dataset, int series, int item);
070
071}