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 * DefaultKeyedValueDataset.java 029 * ----------------------------- 030 * (C) Copyright 2003-2005, by Object Refinery Limited. 031 * 032 * Original Author: David Gilbert (for Object Refinery Limited); 033 * Contributor(s): -; 034 * 035 * $Id $ 036 * 037 * Changes 038 * ------- 039 * 27-Mar-2003 : Version 1 (DG); 040 * 18-Aug-2003 : Implemented Cloneable (DG); 041 * 042 */ 043 044 package org.jfree.data.general; 045 046 import java.io.Serializable; 047 048 import org.jfree.data.DefaultKeyedValue; 049 import org.jfree.data.KeyedValue; 050 import org.jfree.util.ObjectUtilities; 051 052 /** 053 * A default implementation of the {@link KeyedValueDataset} interface. 054 */ 055 public class DefaultKeyedValueDataset extends AbstractDataset 056 implements KeyedValueDataset, 057 Serializable { 058 059 /** For serialization. */ 060 private static final long serialVersionUID = -8149484339560406750L; 061 062 /** Storage for the data. */ 063 private KeyedValue data; 064 065 /** 066 * Constructs a new dataset, initially empty. 067 */ 068 public DefaultKeyedValueDataset() { 069 this(null); 070 } 071 072 /** 073 * Creates a new dataset with the specified initial value. 074 * 075 * @param key the key. 076 * @param value the value (<code>null</code> permitted). 077 */ 078 public DefaultKeyedValueDataset(Comparable key, Number value) { 079 this(new DefaultKeyedValue(key, value)); 080 } 081 082 /** 083 * Creates a new dataset that uses the data from a {@link KeyedValue} 084 * instance. 085 * 086 * @param data the data (<code>null</code> permitted). 087 */ 088 public DefaultKeyedValueDataset(KeyedValue data) { 089 this.data = data; 090 } 091 092 /** 093 * Returns the key associated with the value, or <code>null</code> if the 094 * dataset has no data item. 095 * 096 * @return The key. 097 */ 098 public Comparable getKey() { 099 Comparable result = null; 100 if (this.data != null) { 101 result = this.data.getKey(); 102 } 103 return result; 104 } 105 106 /** 107 * Returns the value. 108 * 109 * @return The value (possibly <code>null</code>). 110 */ 111 public Number getValue() { 112 Number result = null; 113 if (this.data != null) { 114 result = this.data.getValue(); 115 } 116 return result; 117 } 118 119 /** 120 * Updates the value. 121 * 122 * @param value the new value (<code>null</code> permitted). 123 */ 124 public void updateValue(Number value) { 125 if (this.data == null) { 126 throw new RuntimeException("updateValue: can't update null."); 127 } 128 setValue(this.data.getKey(), value); 129 } 130 131 /** 132 * Sets the value for the dataset and sends a {@link DatasetChangeEvent} to 133 * all registered listeners. 134 * 135 * @param key the key. 136 * @param value the value (<code>null</code> permitted). 137 */ 138 public void setValue(Comparable key, Number value) { 139 this.data = new DefaultKeyedValue(key, value); 140 notifyListeners(new DatasetChangeEvent(this, this)); 141 } 142 143 /** 144 * Tests this dataset for equality with an arbitrary object. 145 * 146 * @param obj the object. 147 * 148 * @return A boolean. 149 */ 150 public boolean equals(Object obj) { 151 152 if (obj == this) { 153 return true; 154 } 155 if (!(obj instanceof KeyedValueDataset)) { 156 return false; 157 } 158 KeyedValueDataset that = (KeyedValueDataset) obj; 159 if (this.data == null) { 160 if (that.getKey() != null || that.getValue() != null) { 161 return false; 162 } 163 return true; 164 } 165 if (!ObjectUtilities.equal(this.data.getKey(), that.getKey())) { 166 return false; 167 } 168 if (!ObjectUtilities.equal(this.data.getValue(), that.getValue())) { 169 return false; 170 } 171 return true; 172 } 173 174 /** 175 * Returns a hash code. 176 * 177 * @return A hash code. 178 */ 179 public int hashCode() { 180 return (this.data != null ? this.data.hashCode() : 0); 181 } 182 183 /** 184 * Creates a clone of the dataset. 185 * 186 * @return A clone. 187 * 188 * @throws CloneNotSupportedException This class will not throw this 189 * exception, but subclasses (if any) might. 190 */ 191 public Object clone() throws CloneNotSupportedException { 192 DefaultKeyedValueDataset clone 193 = (DefaultKeyedValueDataset) super.clone(); 194 return clone; 195 } 196 197 }