001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2021, 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 * FlowLabelGenerator.java
029 * -----------------------
030 * (C) Copyright 2021, by Object Refinery Limited and Contributors.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 */
036
037package org.jfree.chart.labels;
038
039import org.jfree.data.flow.FlowDataset;
040import org.jfree.data.flow.FlowKey;
041
042/**
043 * A label generator for a flow in a flow dataset.
044 * 
045 * @since 1.5.3
046 */
047public interface FlowLabelGenerator {
048    
049    /**
050     * Returns a label for the specified flow.
051     * 
052     * @param dataset  the flow dataset ({@code null} not permitted).
053     * @param key  the flow key ({@code null} not permitted).
054     * 
055     * @return The label (possibly {@code null}). 
056     */
057    String generateLabel(FlowDataset dataset, FlowKey key);
058    
059}
060