001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2013, 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025 * Other names may be trademarks of their respective owners.]
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
044package org.jfree.data.statistics;
045
046import java.io.Serializable;
047
048import 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 */
055public 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    @Override
149    public boolean equals(Object obj) {
150        if (obj == this) {
151            return true;
152        }
153        if (!(obj instanceof MeanAndStandardDeviation)) {
154            return false;
155        }
156        MeanAndStandardDeviation that = (MeanAndStandardDeviation) obj;
157        if (!ObjectUtilities.equal(this.mean, that.mean)) {
158            return false;
159        }
160        if (!ObjectUtilities.equal(
161            this.standardDeviation, that.standardDeviation)
162        ) {
163            return false;
164        }
165        return true;
166    }
167
168    /**
169     * Returns a string representing this instance.
170     *
171     * @return A string.
172     *
173     * @since 1.0.7
174     */
175    @Override
176    public String toString() {
177        return "[" + this.mean + ", " + this.standardDeviation + "]";
178    }
179
180}