Java event handling

Question

import java.awt.Color; import java.awt.Dimension;

import javax.swing.JPanel;
import javax.swing.Timer;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartMouseEvent;
import org.jfree.chart.ChartMouseListener;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.entity.ChartEntity;
import org.jfree.chart.plot.PiePlot;
import org.jfree.chart.plot.PiePlot3D;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.general.PieDataset;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;

/**
 * A simple demonstration application showing how to create a pie chart using
 * data from a {@link DefaultPieDataset}.
 */
public class PieChartDemo1 extends ApplicationFrame implements ChartMouseListener {
private JFreeChart chart; 
private PiePlot plot;
private int angle=270;
private static double explodePercent = 0.99;
private static long count=0;
/**
 * Default constructor.
 *
 * @param title  the frame title.
 */
public PieChartDemo1(String title) {
    super(title);
           this.chart = ChartFactory.createPieChart(
            "Pie Chart Demo 1",  // chart title
            createDataset(),             // data
            true,               // include legend
            true,
            false
        );

        this.plot = (PiePlot) chart.getPlot();
        this.plot.setSectionOutlinesVisible(false);
        this.plot.setNoDataMessage("No data available");
        this.plot.setBackgroundAlpha(0.2f);
        this.plot.setBackgroundPaint(Color.WHITE); 
        this.plot.setExplodePercent("One",.99);
        this.angle=270;
        ChartPanel chartpanel = new ChartPanel(chart, false, false, false, false,      false);   
        chartpanel.setVisible(true);
    chartpanel.addChartMouseListener(this);
    chartpanel.setPreferredSize(new Dimension(500, 270));
    setContentPane(chartpanel);
}

/**
 * Creates a sample dataset.
 *
 * @return A sample dataset.
 */
private static PieDataset createDataset() {
    DefaultPieDataset dataset = new DefaultPieDataset();
    dataset.setValue("One", new Double(43.2));
    dataset.setValue("Two", new Double(10.0));
    dataset.setValue("Three", new Double(27.5));
    dataset.setValue("Four", new Double(17.5));
    dataset.setValue("Five", new Double(11.0));
    dataset.setValue("Six", new Double(19.4));
    return dataset;
}

/**
 * Creates a chart.
 *
 * @param dataset  the dataset.
 *
 * @return A chart.
 */
private static JFreeChart createChart(PieDataset dataset) {

    JFreeChart chart = ChartFactory.createPieChart3D(
        "Pie Chart Demo 1",  // chart title
        dataset,             // data
        true,               // include legend
        true,
        false
    );

    PiePlot plot = (PiePlot) chart.getPlot();
    plot.setSectionOutlinesVisible(false);
    plot.setNoDataMessage("No data available");
    plot.setBackgroundAlpha(0.2f);
    return chart;

}

/**
 * Creates a panel for the demo (used by SuperDemo.java).
 *
 * @return A panel.
 */
public static JPanel createDemoPanel() {
    JFreeChart chart = createChart(createDataset());
    ChartPanel chartpanel = new ChartPanel(chart, false, false, false, false, false);   
    chartpanel.setVisible(true);      
    chartpanel.setPreferredSize(new Dimension(500, 270));
    return new JPanel();
}

/**
 * Starting point for the demonstration application.
 *
 * @param args  ignored.
 */
public static void main(String[] args) {


    PieChartDemo1 demo = new PieChartDemo1("Pie Chart Demo 1");
    demo.pack();
    RefineryUtilities.centerFrameOnScreen(demo);
    demo.setVisible(true);
}

public void chartMouseClicked(ChartMouseEvent chartmouseevent)
{
ChartEntity chartentity = chartmouseevent.getEntity();
if (chartentity != null){
    this.plot.setStartAngle(angle);
    this.angle=angle+5;
    this.plot.setStartAngle(angle);
    this.plot.setExplodePercent("One", .8);
    System.out.println("Mouse clicked: " + chartentity.toString());
}
else
System.out.println("Mouse clicked: null entity.");
}

public void chartMouseMoved(ChartMouseEvent chartmouseevent)
{
int i = chartmouseevent.getTrigger().getX();
int j = chartmouseevent.getTrigger().getY();
ChartEntity chartentity = chartmouseevent.getEntity();
if (chartentity != null)
{
    //this.plot.setStartAngle(angle);
//this.angle=angle-5;
//this.plot.setStartAngle(angle);
    System.out.println("Explode Percent is "+plot.getExplodePercent("One"));        
    Rotator rotator=new Rotator(plot);
    rotator.setInitialDelay(10000000);
    rotator.setDelay(100000000);

    rotator.start();
   //System.out.println("Mouse moved: " + i + ", " + j + ": " + chartentity.toString());
}
//else
//System.out.println("Mouse moved: " + i + ", " + j + ": null entity.");
}

static class Rotator extends Timer   {

    /** The plot. */
    private PiePlot plot;

    /** The angle. */

    private int X,Y;

    /**
     * Constructor.
     *
     * @param plot  the plot.
     */
    Rotator(final PiePlot plot) { 
        super(100,null);         
        this.plot = plot;               

        while(count<999999999&&explodePercent>=0){
        if(explodePercent>0)    
        explodePercent=explodePercent-.0001;
        else
        explodePercent=explodePercent+.0001;
        plot.setExplodePercent("One", explodePercent);
        count++;
        }




    }
}

}

The above code is used to create a chart and I have to develop something like amcharts link

I tried using Timer but the events are not getting delayed irrespective of the delay I use.Can anyone help me in getting the delay? This has nothing to with Jcharts though.This is purely event handling.

Answer 1

Your mouse event handler is never releasing the CPU. The Rotator is not causing the thread to sleep so the whole delay happens as soon as the mouse event is handled.

Answer 2

you are doing the logic that your timer listener should be performing in the constructor of your Rotator. this way you immediately perform the action without the delay. you also dont have anything that is listening for timer events.

instead, you should have your PieChartDemo implement ActionListener and have it do your timer processing:

 public void actionPerformed(ActionEvent actionevent) {
   //you can test if the event has come in from the timer
   if (actionevent.getSource() == myTimer) {
    while(count<999999999&&explodePercent>=0){
      if(explodePercent>0)    
         explodePercent=explodePercent-.0001;
      else
         explodePercent=explodePercent+.0001;
      getPlot().setExplodePercent("One", explodePercent);
     count++;
    }
   }
 }

or something like that.

you will also need to pass in your ActionListener to the constructor:

old:

 Rotator(final PiePlot plot) { 
    super(100,null);   // this passes a null listener to the timer object

new:

 Rotator(final PiePlot plot, ActionListener listener) { 
    super(100, listener); // this will pass in the listener, which will then get timer updates, delayed as you have specified.

here is a good tutorial on swing timers