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 * KeyedValues.java
029 * ----------------
030 * (C) Copyright 2002-2008, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes:
036 * --------
037 * 23-Oct-2002 : Version 1 (DG);
038 * 12-Jan-2005 : Updated Javadocs to specify new behaviour when key
039 *               is not recognised (DG);
040 * ------------- JFREECHART 1.0.0 ---------------------------------------------
041 * 02-May-2006 : Updated API docs (DG);
042 *
043 */
044
045package org.jfree.data;
046
047import java.util.List;
048
049/**
050 * An ordered list of (key, value) items where the keys are unique and
051 * non-<code>null</code>.
052 *
053 * @see Values
054 * @see DefaultKeyedValues
055 */
056public interface KeyedValues extends Values {
057
058    /**
059     * Returns the key associated with the item at a given position.  Note
060     * that some implementations allow re-ordering of the data items, so the
061     * result may be transient.
062     *
063     * @param index  the item index (in the range <code>0</code> to
064     *     <code>getItemCount() - 1</code>).
065     *
066     * @return The key (never <code>null</code>).
067     *
068     * @throws IndexOutOfBoundsException if <code>index</code> is not in the
069     *     specified range.
070     */
071    public Comparable getKey(int index);
072
073    /**
074     * Returns the index for a given key.
075     *
076     * @param key  the key (<code>null</code> not permitted).
077     *
078     * @return The index, or <code>-1</code> if the key is unrecognised.
079     *
080     * @throws IllegalArgumentException if <code>key</code> is
081     *     <code>null</code>.
082     */
083    public int getIndex(Comparable key);
084
085    /**
086     * Returns the keys for the values in the collection.  Note that you can
087     * access the values in this collection by key or by index.  For this
088     * reason, the key order is important - this method should return the keys
089     * in order.  The returned list may be unmodifiable.
090     *
091     * @return The keys (never <code>null</code>).
092     */
093    public List getKeys();
094
095    /**
096     * Returns the value for a given key.
097     *
098     * @param key  the key.
099     *
100     * @return The value (possibly <code>null</code>).
101     *
102     * @throws UnknownKeyException if the key is not recognised.
103     */
104    public Number getValue(Comparable key);
105
106}