001 /* =========================================================== 002 * JFreeChart : a free chart library for the Java(tm) platform 003 * =========================================================== 004 * 005 * (C) Copyright 2000-2005, 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 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 025 * in the United States and other countries.] 026 * 027 * ---------------------- 028 * DefaultKeyedValue.java 029 * ---------------------- 030 * (C) Copyright 2002-2005, by Object Refinery Limited. 031 * 032 * Original Author: David Gilbert (for Object Refinery Limited); 033 * Contributor(s): -; 034 * 035 * $Id: DefaultKeyedValue.java,v 1.6.2.1 2005/10/25 21:29:13 mungady Exp $ 036 * 037 * Changes: 038 * -------- 039 * 31-Oct-2002 : Version 1 (DG); 040 * 13-Mar-2003 : Added equals() method, and implemented Serializable (DG); 041 * 18-Aug-2003 : Implemented Cloneable (DG); 042 * 18-Aug-2004 : Moved from org.jfree.data --> org.jfree.data.base (DG); 043 * 15-Sep-2004 : Added PublicCloneable interface (DG); 044 * 045 */ 046 047 package org.jfree.data; 048 049 import java.io.Serializable; 050 051 import org.jfree.util.PublicCloneable; 052 053 /** 054 * A (key, value) pair. This class provides a default implementation 055 * of the {@link KeyedValue} interface. 056 */ 057 public class DefaultKeyedValue implements KeyedValue, 058 Cloneable, PublicCloneable, 059 Serializable { 060 061 /** For serialization. */ 062 private static final long serialVersionUID = -7388924517460437712L; 063 064 /** The key. */ 065 private Comparable key; 066 067 /** The value. */ 068 private Number value; 069 070 /** 071 * Creates a new (key, value) item. 072 * 073 * @param key the key (should be immutable). 074 * @param value the value (<code>null</code> permitted). 075 */ 076 public DefaultKeyedValue(Comparable key, Number value) { 077 this.key = key; 078 this.value = value; 079 } 080 081 /** 082 * Returns the key. 083 * 084 * @return The key. 085 */ 086 public Comparable getKey() { 087 return this.key; 088 } 089 090 /** 091 * Returns the value. 092 * 093 * @return The value (possibly <code>null</code>). 094 */ 095 public Number getValue() { 096 return this.value; 097 } 098 099 /** 100 * Sets the value. 101 * 102 * @param value the value (<code>null</code> permitted). 103 */ 104 public synchronized void setValue(Number value) { 105 this.value = value; 106 } 107 108 /** 109 * Tests this key-value pair for equality with an arbitrary object. 110 * 111 * @param obj the object (<code>null</code> permitted). 112 * 113 * @return A boolean. 114 */ 115 public boolean equals(Object obj) { 116 if (obj == this) { 117 return true; 118 } 119 if (!(obj instanceof DefaultKeyedValue)) { 120 return false; 121 } 122 // TODO: modify this so that we check for equality with any KeyedValue 123 // rather than specifically a DefaultKeyedValue 124 DefaultKeyedValue that = (DefaultKeyedValue) obj; 125 126 // TODO: the following checks for null should be handled in a utility 127 // method 128 if (this.key != null ? !this.key.equals(that.key) : that.key != null) { 129 return false; 130 } 131 if (this.value != null 132 ? !this.value.equals(that.value) : that.value != null) { 133 return false; 134 } 135 return true; 136 } 137 138 /** 139 * Returns a hash code. 140 * 141 * @return A hash code. 142 */ 143 public int hashCode() { 144 int result; 145 result = (this.key != null ? this.key.hashCode() : 0); 146 result = 29 * result + (this.value != null ? this.value.hashCode() : 0); 147 return result; 148 } 149 150 /** 151 * Returns a clone. It is assumed that both the key and value are 152 * immutable objects, so only the references are cloned, not the objects 153 * themselves. 154 * 155 * @return A clone. 156 * 157 * @throws CloneNotSupportedException Not thrown by this class, but 158 * subclasses (if any) might. 159 */ 160 public Object clone() throws CloneNotSupportedException { 161 DefaultKeyedValue clone = (DefaultKeyedValue) super.clone(); 162 return clone; 163 } 164 165 }