001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, 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 2003-2008, by Object Refinery Limited.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * Changes
036 * -------
037 * 27-Mar-2003 : Version 1 (DG);
038 * 18-Aug-2003 : Implemented Cloneable (DG);
039 *
040 */
041
042 package org.jfree.data.general;
043
044 import java.io.Serializable;
045
046 import org.jfree.data.DefaultKeyedValue;
047 import org.jfree.data.KeyedValue;
048 import org.jfree.util.ObjectUtilities;
049
050 /**
051 * A default implementation of the {@link KeyedValueDataset} interface.
052 */
053 public class DefaultKeyedValueDataset extends AbstractDataset
054 implements KeyedValueDataset, Serializable {
055
056 /** For serialization. */
057 private static final long serialVersionUID = -8149484339560406750L;
058
059 /** Storage for the data. */
060 private KeyedValue data;
061
062 /**
063 * Constructs a new dataset, initially empty.
064 */
065 public DefaultKeyedValueDataset() {
066 this(null);
067 }
068
069 /**
070 * Creates a new dataset with the specified initial value.
071 *
072 * @param key the key.
073 * @param value the value (<code>null</code> permitted).
074 */
075 public DefaultKeyedValueDataset(Comparable key, Number value) {
076 this(new DefaultKeyedValue(key, value));
077 }
078
079 /**
080 * Creates a new dataset that uses the data from a {@link KeyedValue}
081 * instance.
082 *
083 * @param data the data (<code>null</code> permitted).
084 */
085 public DefaultKeyedValueDataset(KeyedValue data) {
086 this.data = data;
087 }
088
089 /**
090 * Returns the key associated with the value, or <code>null</code> if the
091 * dataset has no data item.
092 *
093 * @return The key.
094 */
095 public Comparable getKey() {
096 Comparable result = null;
097 if (this.data != null) {
098 result = this.data.getKey();
099 }
100 return result;
101 }
102
103 /**
104 * Returns the value.
105 *
106 * @return The value (possibly <code>null</code>).
107 */
108 public Number getValue() {
109 Number result = null;
110 if (this.data != null) {
111 result = this.data.getValue();
112 }
113 return result;
114 }
115
116 /**
117 * Updates the value.
118 *
119 * @param value the new value (<code>null</code> permitted).
120 */
121 public void updateValue(Number value) {
122 if (this.data == null) {
123 throw new RuntimeException("updateValue: can't update null.");
124 }
125 setValue(this.data.getKey(), value);
126 }
127
128 /**
129 * Sets the value for the dataset and sends a {@link DatasetChangeEvent} to
130 * all registered listeners.
131 *
132 * @param key the key.
133 * @param value the value (<code>null</code> permitted).
134 */
135 public void setValue(Comparable key, Number value) {
136 this.data = new DefaultKeyedValue(key, value);
137 notifyListeners(new DatasetChangeEvent(this, this));
138 }
139
140 /**
141 * Tests this dataset for equality with an arbitrary object.
142 *
143 * @param obj the object (<code>null</code> permitted).
144 *
145 * @return A boolean.
146 */
147 public boolean equals(Object obj) {
148 if (obj == this) {
149 return true;
150 }
151 if (!(obj instanceof KeyedValueDataset)) {
152 return false;
153 }
154 KeyedValueDataset that = (KeyedValueDataset) obj;
155 if (this.data == null) {
156 if (that.getKey() != null || that.getValue() != null) {
157 return false;
158 }
159 return true;
160 }
161 if (!ObjectUtilities.equal(this.data.getKey(), that.getKey())) {
162 return false;
163 }
164 if (!ObjectUtilities.equal(this.data.getValue(), that.getValue())) {
165 return false;
166 }
167 return true;
168 }
169
170 /**
171 * Returns a hash code.
172 *
173 * @return A hash code.
174 */
175 public int hashCode() {
176 return (this.data != null ? this.data.hashCode() : 0);
177 }
178
179 /**
180 * Creates a clone of the dataset.
181 *
182 * @return A clone.
183 *
184 * @throws CloneNotSupportedException This class will not throw this
185 * exception, but subclasses (if any) might.
186 */
187 public Object clone() throws CloneNotSupportedException {
188 DefaultKeyedValueDataset clone
189 = (DefaultKeyedValueDataset) super.clone();
190 return clone;
191 }
192
193 }