How can I refresh the Category dataset

[ashutosh]

Hi Everyone.

I'm trying to develope a chart that will take the value for the database and display. some data is inserted in the database at some interval, so the volume of the database is increasing.

I want to show the new value in the chart which is continously changing. how can I refresh or how this chart can automaticaly get refreshed when the dataset changes.

what are the methods that I can use to do this???

my code is attached along. Please have a look and give some suggessions, where and how shall I use the DatasetChangeEvent method.

Code: Select all

import java.awt.*;
import javax.swing.*;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.plot.IntervalMarker;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;
import org.jfree.chart.renderer.category.BarRenderer;
import org.jfree.chart.renderer.category.BarRenderer3D;
import org.jfree.ui.RefineryUtilities;
import org.jfree.data.general.DatasetChangeListener;
import org.jfree.data.general.DatasetChangeEvent;


public class ChartProgramTest extends JFrame
{
public String series1 = "Data";
private JPanel jContentPane = null;
private JButton jButton1 =null;
private JButton jButton2 =null;
private DefaultCategoryDataset dataset = new DefaultCategoryDataset();
private ChartPanel chartPanel = null;
static int max=0;

private CategoryDataset createDataset()
{


// row keys...
String category = "ABC";
String series1 = "DATA";

// create the dataset...
DefaultCategoryDataset dataset = new DefaultCategoryDataset();
Database db = new Database();
max = db.getCount();
dataset.addValue(max, series1, category);

return dataset;

}

private JFreeChart getJFreeChart(CategoryDataset dataset)
{
JFreeChart chart = ChartFactory.createBarChart(
"Data Chart", // chart title
"Companies", // domain axis label
"Value", // range axis label
createDataset(), // data
PlotOrientation.VERTICAL, // orientation
true, // include legend
false, // tooltips?
false // URLs?
);


chart.setBackgroundPaint(Color.white);

// get a reference to the plot for further customisation...
CategoryPlot plot = (CategoryPlot) chart.getCategoryPlot();

plot.setBackgroundPaint(Color.lightGray);
plot.setDomainGridlinePaint(Color.white);
plot.setDomainGridlinesVisible(true);
plot.setRangeGridlinePaint(Color.white);

// set the range axis to display integers only...
final NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();
rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());
rangeAxis.setRange(0.0, max*1.5);

// disable bar outlines...
BarRenderer renderer = (BarRenderer) plot.getRenderer();
renderer.setDrawBarOutline(true);

BarRenderer barrenderer = (BarRenderer)plot.getRenderer();
barrenderer.setMaximumBarWidth(0.15);

// set up gradient paints for series...
GradientPaint gp0 = new GradientPaint(0.0f, 0.0f, Color.blue,
0.0f, 0.0f, new Color(0, 0, 64));
renderer.setSeriesPaint(0, gp0);

return chart;
}


private JPanel getJContentPane()
{

jContentPane = new JPanel();
jContentPane.setLayout(new FlowLayout());
jContentPane.setPreferredSize(new Dimension(150,100));
chartPanel = new ChartPanel(getJFreeChart(dataset));
chartPanel.setBounds(new java.awt.Rectangle(14,33,521,300));
chartPanel.setRefreshBuffer(true);

jButton1 = new JButton("Exit");
jButton1.setBounds(new java.awt.Rectangle(15,9,109,20));

jButton2 = new JButton("Refresh");
jButton2.setBounds(new java.awt.Rectangle(15,9,109,20));

jButton1.addActionListener(new java.awt.event.ActionListener()
{
public void actionPerformed(java.awt.event.ActionEvent e)
{
System.exit(0);
}
});

jButton2.addActionListener(new java.awt.event.ActionListener()
{
public void actionPerformed(java.awt.event.ActionEvent e)
{
chartPanel.repaint();
}
});


jContentPane.add(chartPanel, null);
jContentPane.add(jButton1, null);
jContentPane.add(jButton2, null);

return jContentPane;
}

private void initialize()
{
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setResizable(false);
this.setSize(720,500);
this.setContentPane(getJContentPane());
this.setTitle("Bar Chart");
}

public static void main(String[] args) throws InterruptedException, Exception
{
ChartProgramTest cpgm = new ChartProgramTest();
cpgm.initialize();
RefineryUtilities.centerFrameOnScreen(cpgm);
cpgm.show();

}
}

[code]


Please help me !!!

-Ashutosh