001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2022, by David Gilbert 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 * KeyedValuesItemKey.java
029 * -----------------------
030 * (C) Copyright 2014-2022, by David Gilbert.
031 *
032 * Original Author:  David Gilbert;
033 * Contributor(s):   Tracy Hiltbrand;
034 *
035 */
036
037package org.jfree.data;
038
039import java.io.Serializable;
040import java.util.Objects;
041import org.jfree.chart.internal.Args;
042
043/**
044 * A reference to an item in a {link KeyedValues} instance.
045 * 
046 * @param <K> The key type.
047 */
048public class KeyedValuesItemKey<K extends Comparable<K>> implements ItemKey, 
049        Serializable {
050    
051    /** The key for the item. */
052    K key;
053    
054    /**
055     * Creates a new instance.
056     * 
057     * @param key  the key ({@code null} not permitted).
058     */
059    public KeyedValuesItemKey(K key) {
060        Args.nullNotPermitted(key, "key");
061        this.key = key;
062    }
063    
064    /**
065     * Returns the key.
066     * 
067     * @return The key (never {@code null}). 
068     */
069    public K getKey() {
070        return this.key;
071    }
072    
073    /**
074     * Tests this instance for equality with an arbitrary object.
075     * 
076     * @param obj  the object ({@code null} not permitted).
077     * 
078     * @return A boolean.
079     */
080    @Override
081    public boolean equals(Object obj) {
082        if (obj == this) {
083            return true;
084        }
085        if (!(obj instanceof KeyedValuesItemKey)) {
086            return false;
087        }
088        KeyedValuesItemKey that = (KeyedValuesItemKey) obj;
089        if (!this.key.equals(that.key)) {
090            return false;
091        }
092        return true;
093    }
094
095    @Override
096    public int hashCode(){
097        int hash = 7;
098        hash = 23 * hash + Objects.hashCode(this.key);
099        return hash;
100    }
101    
102    @Override
103    public String toJSONString() {
104        StringBuilder sb = new StringBuilder();
105        sb.append("{\"key\": \"").append(this.key.toString()).append("\"}");
106        return sb.toString();
107    }
108
109    @Override
110    public String toString() {
111        StringBuilder sb = new StringBuilder();
112        sb.append("KeyedValuesItemKey[");
113        sb.append(this.key.toString());
114        sb.append("]");
115        return sb.toString();
116    }
117}