001/* ===========================================================
002 * Orson Charts : a 3D chart library for the Java(tm) platform
003 * ===========================================================
004 * 
005 * (C)opyright 2013-2016, by Object Refinery Limited.  All rights reserved.
006 * 
007 * http://www.object-refinery.com/orsoncharts/index.html
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 com.orsoncharts.data;
034
035import java.util.List;
036
037/**
038 * A list of values that are associated with unique keys.
039 */
040public interface KeyedValues<T> extends Values<T> { 
041
042    /**
043     * Returns the key for the specified item in the list.
044     * 
045     * @param index  the item index.
046     * 
047     * @return The key. 
048     */
049    public Comparable<?> getKey(int index);
050  
051    /**
052     * Returns the index for the specified key, or {@code -1} if the key
053     * is not present in the list.
054     * 
055     * @param key  the key ({@code null} not permitted).
056     * 
057     * @return The item index, or {@code -1}. 
058     */
059    public int getIndex(Comparable<?> key);
060  
061    /**
062     * Returns a list of all the keys.  Note that the list will be a copy, so
063     * modifying it will not impact this data structure.
064     * 
065     * @return A list of keys (possibly empty, but never {@code null}).
066     */
067    public List<Comparable<?>> getKeys();
068
069    /**
070     * Returns the value associated with the specified key, or 
071     * {@code null}.
072     * 
073     * @param key  the key ({@code null} not permitted).
074     * 
075     * @return The value (possibly {@code null}). 
076     */
077    public T getValue(Comparable<?> key);
078
079}