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 * DefaultValueDataset.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 * 03-Mar-2005 : Implemented PublicCloneable (DG); 042 * 043 */ 044 045 package org.jfree.data.general; 046 047 import java.io.Serializable; 048 049 import org.jfree.util.ObjectUtilities; 050 import org.jfree.util.PublicCloneable; 051 052 /** 053 * A dataset that stores a single value. This class provides a default 054 * implementation of the {@link ValueDataset} interface. 055 */ 056 public class DefaultValueDataset extends AbstractDataset 057 implements ValueDataset, 058 Cloneable, PublicCloneable, 059 Serializable { 060 061 /** For serialization. */ 062 private static final long serialVersionUID = 8137521217249294891L; 063 064 /** The value. */ 065 private Number value; 066 067 /** 068 * Constructs a new dataset, initially empty. 069 */ 070 public DefaultValueDataset() { 071 this(null); 072 } 073 074 /** 075 * Creates a new dataset. 076 * 077 * @param value the value. 078 */ 079 public DefaultValueDataset(double value) { 080 this(new Double(value)); 081 } 082 083 /** 084 * Creates a new dataset. 085 * 086 * @param value the initial value. 087 */ 088 public DefaultValueDataset(Number value) { 089 this.value = value; 090 } 091 092 /** 093 * Returns the value. 094 * 095 * @return The value (possibly <code>null</code>). 096 */ 097 public Number getValue() { 098 return this.value; 099 } 100 101 /** 102 * Sets the value and sends a {@link DatasetChangeEvent} to all registered 103 * listeners. 104 * 105 * @param value the new value (<code>null</code> permitted). 106 */ 107 public void setValue(Number value) { 108 this.value = value; 109 notifyListeners(new DatasetChangeEvent(this, this)); 110 } 111 112 /** 113 * Tests this dataset for equality with an arbitrary object. 114 * 115 * @param obj the object. 116 * 117 * @return A boolean. 118 */ 119 public boolean equals(Object obj) { 120 121 if (obj == null) { 122 return false; 123 } 124 125 if (obj == this) { 126 return true; 127 } 128 129 if (obj instanceof ValueDataset) { 130 ValueDataset vd = (ValueDataset) obj; 131 return ObjectUtilities.equal(this.value, vd.getValue()); 132 } 133 134 return false; 135 } 136 137 /** 138 * Returns a hash code. 139 * 140 * @return A hash code. 141 */ 142 public int hashCode() { 143 return (this.value != null ? this.value.hashCode() : 0); 144 } 145 146 }