001/* ===========================================================
002 * Orson Charts : a 3D chart library for the Java(tm) platform
003 * ===========================================================
004 * 
005 * (C)opyright 2013-2022, by David Gilbert.  All rights reserved.
006 * 
007 * https://github.com/jfree/orson-charts
008 * 
009 * This program is free software: you can redistribute it and/or modify
010 * it under the terms of the GNU General Public License as published by
011 * the Free Software Foundation, either version 3 of the License, or
012 * (at your option) any later version.
013 *
014 * This program is distributed in the hope that it will be useful,
015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
017 * GNU General Public License for more details.
018 *
019 * You should have received a copy of the GNU General Public License
020 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
021 * 
022 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
023 * Other names may be trademarks of their respective owners.]
024 * 
025 * If you do not wish to be bound by the terms of the GPL, an alternative
026 * commercial license can be purchased.  For details, please see visit the
027 * Orson Charts home page:
028 * 
029 * http://www.object-refinery.com/orsoncharts/index.html
030 * 
031 */
032
033package org.jfree.chart3d.data;
034
035/**
036 * A {@code (key, value)} pair that is used as a building block for some
037 * data structures for the charts.
038 * 
039 * @param <K>  The key type.
040 * @param <T>  The value type.
041 */
042public interface KeyedValue<K extends Comparable<K>, T> {
043  
044    /**
045     * Returns the key (by design, this key is required to be 
046     * non-{@code null}).
047     * 
048     * @return The key (never {@code null}). 
049     */
050    K getKey();
051  
052    /**
053     * Returns the value.
054     * 
055     * @return The value (possibly {@code null}). 
056     */
057    T getValue();
058  
059}