jfreechart example source code file (StatisticsTests.java)

This example jfreechart source code file (StatisticsTests.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

arraylist, arraylist, classcastexception, double, double, epsilon, epsilon, illegalargumentexception, list, nullpointerexception, number, number, statisticstests, testcase, util

The jfreechart StatisticsTests.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * --------------------
 * StatisticsTests.java
 * --------------------
 * (C) Copyright 2004-2008, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 25-Mar-2004 : Version 1 (DG);
 * 04-Oct-2004 : Eliminated NumberUtils usage (DG);
 *
 */

package org.jfree.data.statistics.junit;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

import org.jfree.data.statistics.Statistics;

/**
 * Tests for the {@link Statistics} class.
 */
public class StatisticsTests extends TestCase {

    /**
     * Returns the tests as a test suite.
     *
     * @return The test suite.
     */
    public static Test suite() {
        return new TestSuite(StatisticsTests.class);
    }

    /**
     * Constructs a new set of tests.
     *
     * @param name  the name of the tests.
     */
    public StatisticsTests(String name) {
        super(name);
    }

    /**
     * Some checks for the calculateMean(Number[]) and
     * calculateMean(Number[], boolean) methods.
     */
    public void testCalculateMean_Array() {

        // try null array
        boolean pass = false;
        try {
            Statistics.calculateMean((Number[]) null);
        }
        catch (IllegalArgumentException e) {
            pass = true;
        }
        assertTrue(pass);

        pass = false;
        try {
            Statistics.calculateMean((Number[]) null, false);
        }
        catch (IllegalArgumentException e) {
            pass = true;
        }
        assertTrue(pass);

        // try an array containing no items
        assertTrue(Double.isNaN(Statistics.calculateMean(new Number[0])));
        assertTrue(Double.isNaN(Statistics.calculateMean(new Number[0],
                false)));

        // try an array containing a single Number
        Number[] values = new Number[] {new Double(1.0)};
        assertEquals(1.0, Statistics.calculateMean(values), EPSILON);
        assertEquals(1.0, Statistics.calculateMean(values, true), EPSILON);
        assertEquals(1.0, Statistics.calculateMean(values, false), EPSILON);

        // try an array containing a single Number and a null
        values = new Number[] {new Double(1.0), null};
        assertTrue(Double.isNaN(Statistics.calculateMean(values)));
        assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
        assertEquals(1.0, Statistics.calculateMean(values, false), EPSILON);

        // try an array containing a single Number and a NaN
        values = new Number[] {new Double(1.0), new Double(Double.NaN)};
        assertTrue(Double.isNaN(Statistics.calculateMean(values)));
        assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
        assertEquals(1.0, Statistics.calculateMean(values, false), EPSILON);
    }

    /**
     * Some checks for the calculateMean(Collection) and
     * calculateMean(Collection, boolean) methods.
     */
    public void testCalculateMean_Collection() {

        // try a null collection
        boolean pass = false;
        try {
            Statistics.calculateMean((Collection) null);
        }
        catch (IllegalArgumentException e) {
            pass = true;
        }
        assertTrue(pass);

        pass = false;
        try {
            Statistics.calculateMean((Collection) null, false);
        }
        catch (IllegalArgumentException e) {
            pass = true;
        }
        assertTrue(pass);

        // try an empty collection
        List values = new ArrayList();
        assertTrue(Double.isNaN(Statistics.calculateMean(values)));
        assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
        assertTrue(Double.isNaN(Statistics.calculateMean(values, false)));

        // try a collection with a single number
        values.add(new Double(9.0));
        assertEquals(9.0, Statistics.calculateMean(values), EPSILON);
        assertEquals(9.0, Statistics.calculateMean(values, true), EPSILON);
        assertEquals(9.0, Statistics.calculateMean(values, false), EPSILON);

        // try a collection with a single number plus a null
        values.add(null);
        assertTrue(Double.isNaN(Statistics.calculateMean(values)));
        assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
        assertEquals(9.0, Statistics.calculateMean(values, false), EPSILON);

        // try a collection with a single number plus a NaN
        values.clear();
        values.add(new Double(9.0));
        values.add(new Double(Double.NaN));
        assertTrue(Double.isNaN(Statistics.calculateMean(values)));
        assertTrue(Double.isNaN(Statistics.calculateMean(values, true)));
        assertEquals(9.0, Statistics.calculateMean(values, false), EPSILON);

        // try a collection with several numbers
        values = new ArrayList();
        values.add(new Double(9.0));
        values.add(new Double(3.0));
        values.add(new Double(2.0));
        values.add(new Double(2.0));
        double mean = Statistics.calculateMean(values);
        assertEquals(4.0, mean, EPSILON);

        // a Collection containing a NaN will return Double.NaN for the result
        values.add(new Double(Double.NaN));
        assertTrue(Double.isNaN(Statistics.calculateMean(values)));
    }

    static final double EPSILON = 0.0000000001;

    /**
     * Some checks for the calculateMedian(List, boolean) method.
     */
    public void testCalculateMedian() {

        // check null list
        assertTrue(Double.isNaN(Statistics.calculateMedian(null, false)));
        assertTrue(Double.isNaN(Statistics.calculateMedian(null, true)));

        // check empty list
        List list = new ArrayList();
        assertTrue(Double.isNaN(Statistics.calculateMedian(list, false)));
        assertTrue(Double.isNaN(Statistics.calculateMedian(list, true)));

        // check list containing null
        list.add(null);
        boolean pass = false;
        try {
            Statistics.calculateMedian(list, false);
        }
        catch (NullPointerException e) {
            pass = true;
        }
        assertTrue(pass);

        pass = false;
        try {
            Statistics.calculateMedian(list, true);
        }
        catch (NullPointerException e) {
            pass = true;
        }
        assertTrue(pass);

        // check a list containing a non-Number object
        list.clear();
        list.add("Not a number");
        pass = false;
        try {
            Statistics.calculateMedian(list, false);
        }
        catch (ClassCastException e) {
            pass = true;
        }
        assertTrue(pass);

        pass = false;
        try {
            Statistics.calculateMedian(list, true);
        }
        catch (ClassCastException e) {
            pass = true;
        }
        assertTrue(pass);

    }

    /**
     * A test for the calculateMedian() method.
     */
    public void testCalculateMedian1() {
        List values = new ArrayList();
        values.add(new Double(1.0));
        double median = Statistics.calculateMedian(values);
        assertEquals(1.0, median, 0.0000001);
    }

    /**
     * A test for the calculateMedian() method.
     */
    public void testCalculateMedian2() {
        List values = new ArrayList();
        values.add(new Double(2.0));
        values.add(new Double(1.0));
        double median = Statistics.calculateMedian(values);
        assertEquals(1.5, median, 0.0000001);
    }

    /**
     * A test for the calculateMedian() method.
     */
    public void testCalculateMedian3() {
        List values = new ArrayList();
        values.add(new Double(1.0));
        values.add(new Double(2.0));
        values.add(new Double(3.0));
        values.add(new Double(6.0));
        values.add(new Double(5.0));
        values.add(new Double(4.0));
        double median = Statistics.calculateMedian(values);
        assertEquals(3.5, median, 0.0000001);
    }

    /**
     * A test for the calculateMedian() method.
     */
    public void testCalculateMedian4() {
        List values = new ArrayList();
        values.add(new Double(7.0));
        values.add(new Double(2.0));
        values.add(new Double(3.0));
        values.add(new Double(5.0));
        values.add(new Double(4.0));
        values.add(new Double(6.0));
        values.add(new Double(1.0));
        double median = Statistics.calculateMedian(values);
        assertEquals(4.0, median, 0.0000001);
    }

    /**
     * A test using some real data that caused a problem at one point.
     */
    public void testCalculateMedian5() {
        List values = new ArrayList();
        values.add(new Double(11.228692993861783));
        values.add(new Double(11.30823353859889));
        values.add(new Double(11.75312904769314));
        values.add(new Double(11.825102897465314));
        values.add(new Double(10.184252778401783));
        values.add(new Double(12.207951828057766));
        values.add(new Double(10.68841994040566));
        values.add(new Double(12.099522004479438));
        values.add(new Double(11.508874945056881));
        values.add(new Double(12.052517729558513));
        values.add(new Double(12.401481645578734));
        values.add(new Double(12.185377793028543));
        values.add(new Double(10.666372951930315));
        values.add(new Double(11.680978041499548));
        values.add(new Double(11.06528277406718));
        values.add(new Double(11.36876492904596));
        values.add(new Double(11.927565516175939));
        values.add(new Double(11.39307785978655));
        values.add(new Double(11.989603679523857));
        values.add(new Double(12.009834360354864));
        values.add(new Double(10.653351822461559));
        values.add(new Double(11.851776254376754));
        values.add(new Double(11.045441544755946));
        values.add(new Double(11.993674040560624));
        values.add(new Double(12.898219965238944));
        values.add(new Double(11.97095782819647));
        values.add(new Double(11.73234406745488));
        values.add(new Double(11.649006017243991));
        values.add(new Double(12.20549704915365));
        values.add(new Double(11.799723639384919));
        values.add(new Double(11.896208658005628));
        values.add(new Double(12.164149111823424));
        values.add(new Double(12.042795103513766));
        values.add(new Double(12.114839532596426));
        values.add(new Double(12.166609097075824));
        values.add(new Double(12.183017546225935));
        values.add(new Double(11.622009125845342));
        values.add(new Double(11.289365786738633));
        values.add(new Double(12.462984323671568));
        values.add(new Double(11.573494921030598));
        values.add(new Double(10.862867940485804));
        values.add(new Double(12.018186939664872));
        values.add(new Double(10.418046849313018));
        values.add(new Double(11.326344465881341));
        double median = Statistics.calculateMedian(values, true);
        assertEquals(11.812413268425116, median, 0.000001);
        Collections.sort(values);
        double median2 = Statistics.calculateMedian(values, false);
        assertEquals(11.812413268425116, median2, 0.000001);
    }

    /**
     * A test for the calculateMedian() method.
     */
    public void testCalculateMedian6() {
        List values = new ArrayList();
        values.add(new Double(7.0));
        values.add(new Double(2.0));
        values.add(new Double(3.0));
        values.add(new Double(5.0));
        values.add(new Double(4.0));
        values.add(new Double(6.0));
        values.add(new Double(1.0));
        double median = Statistics.calculateMedian(values, 0, 2);
        assertEquals(3.0, median, 0.0000001);
    }

    /**
     * A simple test for the correlation calculation.
     */
    public void testCorrelation1() {
        Number[] data1 = new Number[3];
        data1[0] = new Double(1);
        data1[1] = new Double(2);
        data1[2] = new Double(3);
        Number[] data2 = new Number[3];
        data2[0] = new Double(1);
        data2[1] = new Double(2);
        data2[2] = new Double(3);
        double r = Statistics.getCorrelation(data1, data2);
        assertEquals(1.0, r, 0.00000001);
    }

    /**
     * A simple test for the correlation calculation.
     *
     * http://trochim.human.cornell.edu/kb/statcorr.htm
     */
    public void testCorrelation2() {
        Number[] data1 = new Number[20];
        data1[0] = new Double(68);
        data1[1] = new Double(71);
        data1[2] = new Double(62);
        data1[3] = new Double(75);
        data1[4] = new Double(58);
        data1[5] = new Double(60);
        data1[6] = new Double(67);
        data1[7] = new Double(68);
        data1[8] = new Double(71);
        data1[9] = new Double(69);
        data1[10] = new Double(68);
        data1[11] = new Double(67);
        data1[12] = new Double(63);
        data1[13] = new Double(62);
        data1[14] = new Double(60);
        data1[15] = new Double(63);
        data1[16] = new Double(65);
        data1[17] = new Double(67);
        data1[18] = new Double(63);
        data1[19] = new Double(61);
        Number[] data2 = new Number[20];
        data2[0] = new Double(4.1);
        data2[1] = new Double(4.6);
        data2[2] = new Double(3.8);
        data2[3] = new Double(4.4);
        data2[4] = new Double(3.2);
        data2[5] = new Double(3.1);
        data2[6] = new Double(3.8);
        data2[7] = new Double(4.1);
        data2[8] = new Double(4.3);
        data2[9] = new Double(3.7);
        data2[10] = new Double(3.5);
        data2[11] = new Double(3.2);
        data2[12] = new Double(3.7);
        data2[13] = new Double(3.3);
        data2[14] = new Double(3.4);
        data2[15] = new Double(4.0);
        data2[16] = new Double(4.1);
        data2[17] = new Double(3.8);
        data2[18] = new Double(3.4);
        data2[19] = new Double(3.6);
        double r = Statistics.getCorrelation(data1, data2);
        assertEquals(0.7306356862792885, r, 0.000000000001);
    }

    /**
     * Some checks for the getStdDev() method.
     */
    public void testGetStdDev() {

        // try null argument
        boolean pass = false;
        try {
            Statistics.getStdDev(null);
        }
        catch (IllegalArgumentException e) {
            pass = true;
        }
        assertTrue(pass);

        // try zero length array
        pass = false;
        try {
            Statistics.getStdDev(new Double[0]);
        }
        catch (IllegalArgumentException e) {
            pass = true;
        }
        assertTrue(pass);

        // try single value
        assertTrue(Double.isNaN(Statistics.getStdDev(new Double[]
                {new Double(1.0)})));
    }

}