Java tutorial
/* =========================================================== * JFreeChart : a free chart library for the Java(tm) platform * =========================================================== * * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors. * * Project Info: http://www.jfree.org/jfreechart/index.html * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public * License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, * USA. * * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. * Other names may be trademarks of their respective owners.] * * ---------------- * KeyedValues.java * ---------------- * (C) Copyright 2002-2008, by Object Refinery Limited. * * Original Author: David Gilbert (for Object Refinery Limited); * Contributor(s): -; * * Changes: * -------- * 23-Oct-2002 : Version 1 (DG); * 12-Jan-2005 : Updated Javadocs to specify new behaviour when key * is not recognised (DG); * ------------- JFREECHART 1.0.0 --------------------------------------------- * 02-May-2006 : Updated API docs (DG); * */ package org.jfree.data; import java.util.List; /** * An ordered list of (key, value) items where the keys are unique and * non-<code>null</code>. * * @see Values * @see DefaultKeyedValues */ public interface KeyedValues extends Values { /** * Returns the key associated with the item at a given position. Note * that some implementations allow re-ordering of the data items, so the * result may be transient. * * @param index the item index (in the range <code>0</code> to * <code>getItemCount() - 1</code>). * * @return The key (never <code>null</code>). * * @throws IndexOutOfBoundsException if <code>index</code> is not in the * specified range. */ public Comparable getKey(int index); /** * Returns the index for a given key. * * @param key the key (<code>null</code> not permitted). * * @return The index, or <code>-1</code> if the key is unrecognised. * * @throws IllegalArgumentException if <code>key</code> is * <code>null</code>. */ public int getIndex(Comparable key); /** * Returns the keys for the values in the collection. Note that you can * access the values in this collection by key or by index. For this * reason, the key order is important - this method should return the keys * in order. The returned list may be unmodifiable. * * @return The keys (never <code>null</code>). */ public List getKeys(); /** * Returns the value for a given key. * * @param key the key. * * @return The value (possibly <code>null</code>). * * @throws UnknownKeyException if the key is not recognised. */ public Number getValue(Comparable key); }