Java tutorial
/* =========================================================== * JFreeChart : a free chart library for the Java(tm) platform * =========================================================== * * (C) Copyright 2000-2004, 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., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. * * [Java is a trademark or registered trademark of Sun Microsystems, Inc. * in the United States and other countries.] * * ------------------ * HistogramDemo.java * ------------------ * (C) Copyright 2003, 2004, by Jelai Wang and Contributors. * * Original Author: Jelai Wang (jelaiw AT mindspring.com); * Contributor(s): David Gilbert (for Object Refinery Limited); * * $Id: HistogramDemo.java,v 1.8 2004/04/26 19:11:54 taqua Exp $ * * Changes * ------- * 06-Jul-2003 : Version 1, contributed by Jelai Wang (DG); * 07-Jul-2003 : Modified to display chart on screen, consistent with the other JFreeChart demo * applications (DG); * 01-Mar-2004 : Modified for updates to HistogramDataset (DG); * */ package org.jfree.chart.demo; import java.io.IOException; import java.util.Random; import org.jfree.chart.ChartFactory; import org.jfree.chart.ChartPanel; import org.jfree.chart.JFreeChart; import org.jfree.chart.plot.PlotOrientation; import org.jfree.data.statistics.HistogramDataset; import org.jfree.data.statistics.HistogramType; import org.jfree.data.xy.IntervalXYDataset; import org.jfree.ui.ApplicationFrame; import org.jfree.ui.RefineryUtilities; /** * A demo of the {@link HistogramDataset} class. * * @author Jelai Wang, jelaiw AT mindspring.com */ public class HistogramDemo extends ApplicationFrame { /** For generating random numbers. */ static Random random = new Random(); /** * Creates a new demo. * * @param title the frame title. */ public HistogramDemo(final String title) { super(title); final IntervalXYDataset dataset = createDataset(); final JFreeChart chart = createChart(dataset); final ChartPanel chartPanel = new ChartPanel(chart); chartPanel.setPreferredSize(new java.awt.Dimension(500, 270)); chartPanel.setMouseZoomable(true, false); setContentPane(chartPanel); } /** * Creates a sample {@link HistogramDataset}. * * @return The dataset. */ private IntervalXYDataset createDataset() { final HistogramDataset dataset = new HistogramDataset(); dataset.setType(HistogramType.RELATIVE_FREQUENCY); dataset.addSeries("H1", gaussianData(1000, 3.0), 20); dataset.addSeries("H0", gaussianData(1000, 0), 20); return dataset; } // **************************************************************************** // * JFREECHART DEVELOPER GUIDE * // * The JFreeChart Developer Guide, written by David Gilbert, is available * // * to purchase from Object Refinery Limited: * // * * // * http://www.object-refinery.com/jfreechart/guide.html * // * * // * Sales are used to provide funding for the JFreeChart project - please * // * support us so that we can continue developing free software. * // **************************************************************************** /** * Creates a chart. * * @param dataset a dataset. * * @return The chart. */ private JFreeChart createChart(final IntervalXYDataset dataset) { final JFreeChart chart = ChartFactory.createHistogram("Histogram Demo", null, null, dataset, PlotOrientation.VERTICAL, true, false, false); chart.getXYPlot().setForegroundAlpha(0.75f); return chart; } /** * Generates an array of sample data. * * @param size the array size. * @param shift the shift from zero. * * @return The array of sample data. */ private static double[] gaussianData(final int size, final double shift) { final double[] d = new double[size]; for (int i = 0; i < d.length; i++) { d[i] = random.nextGaussian() + shift; } return d; } /** * The starting point for the demo. * * @param args ignored. * * @throws IOException if there is a problem saving the file. */ public static void main(final String[] args) throws IOException { final HistogramDemo demo = new HistogramDemo("Histogram Demo"); demo.pack(); RefineryUtilities.centerFrameOnScreen(demo); demo.setVisible(true); } }