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 * MeanAndStandardDeviation.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 * 05-Feb-2002 : Version 1 (DG);
038 * 05-Feb-2005 : Added equals() method and implemented Serializable (DG);
039 * 02-Oct-2007 : Added getMeanValue() and getStandardDeviationValue() methods
040 * for convenience, and toString() method for debugging (DG);
041 *
042 */
043
044 package org.jfree.data.statistics;
045
046 import java.io.Serializable;
047
048 import org.jfree.util.ObjectUtilities;
049
050 /**
051 * A simple data structure that holds a mean value and a standard deviation
052 * value. This is used in the
053 * {@link org.jfree.data.statistics.DefaultStatisticalCategoryDataset} class.
054 */
055 public class MeanAndStandardDeviation implements Serializable {
056
057 /** For serialization. */
058 private static final long serialVersionUID = 7413468697315721515L;
059
060 /** The mean. */
061 private Number mean;
062
063 /** The standard deviation. */
064 private Number standardDeviation;
065
066 /**
067 * Creates a new mean and standard deviation record.
068 *
069 * @param mean the mean.
070 * @param standardDeviation the standard deviation.
071 */
072 public MeanAndStandardDeviation(double mean, double standardDeviation) {
073 this(new Double(mean), new Double(standardDeviation));
074 }
075
076 /**
077 * Creates a new mean and standard deviation record.
078 *
079 * @param mean the mean (<code>null</code> permitted).
080 * @param standardDeviation the standard deviation (<code>null</code>
081 * permitted.
082 */
083 public MeanAndStandardDeviation(Number mean, Number standardDeviation) {
084 this.mean = mean;
085 this.standardDeviation = standardDeviation;
086 }
087
088 /**
089 * Returns the mean.
090 *
091 * @return The mean.
092 */
093 public Number getMean() {
094 return this.mean;
095 }
096
097 /**
098 * Returns the mean as a double primitive. If the underlying mean is
099 * <code>null</code>, this method will return <code>Double.NaN</code>.
100 *
101 * @return The mean.
102 *
103 * @see #getMean()
104 *
105 * @since 1.0.7
106 */
107 public double getMeanValue() {
108 double result = Double.NaN;
109 if (this.mean != null) {
110 result = this.mean.doubleValue();
111 }
112 return result;
113 }
114
115 /**
116 * Returns the standard deviation.
117 *
118 * @return The standard deviation.
119 */
120 public Number getStandardDeviation() {
121 return this.standardDeviation;
122 }
123
124 /**
125 * Returns the standard deviation as a double primitive. If the underlying
126 * standard deviation is <code>null</code>, this method will return
127 * <code>Double.NaN</code>.
128 *
129 * @return The standard deviation.
130 *
131 * @since 1.0.7
132 */
133 public double getStandardDeviationValue() {
134 double result = Double.NaN;
135 if (this.standardDeviation != null) {
136 result = this.standardDeviation.doubleValue();
137 }
138 return result;
139 }
140
141 /**
142 * Tests this instance for equality with an arbitrary object.
143 *
144 * @param obj the object (<code>null</code> permitted).
145 *
146 * @return A boolean.
147 */
148 public boolean equals(Object obj) {
149 if (obj == this) {
150 return true;
151 }
152 if (!(obj instanceof MeanAndStandardDeviation)) {
153 return false;
154 }
155 MeanAndStandardDeviation that = (MeanAndStandardDeviation) obj;
156 if (!ObjectUtilities.equal(this.mean, that.mean)) {
157 return false;
158 }
159 if (!ObjectUtilities.equal(
160 this.standardDeviation, that.standardDeviation)
161 ) {
162 return false;
163 }
164 return true;
165 }
166
167 /**
168 * Returns a string representing this instance.
169 *
170 * @return A string.
171 *
172 * @since 1.0.7
173 */
174 public String toString() {
175 return "[" + this.mean + ", " + this.standardDeviation + "]";
176 }
177
178 }