communication between turbine servlets and JFreeChart

[OSullivan, Michael]

Hi

I am trying to get my turbine app to display a dynamic chart using =
Jfreechart and Velocity templating but to no avail. I've been using the
= example below which was sent via one of the forum threads. I've
created = a Java Screen class (i.e not an action class) exactly the same
as in the = attached code and I have included the following image tag in
my velocity = template but to no avail.=20

<img src="$link.setPage("mrtg,Image.vm")" border="0"/>

To start I would just like to get this example working and then try and
= add tooltips and url drill down to the image. Should this be possible
= using the method outlined below. Any help would be greatly
appreciated.

Thanks
Regards, Mike


########################################################################
#=
#########################################################


Hi,

here is a simple example:

package de.byteaction.modules.screens.mrtg;


import org.apache.turbine.modules.screens.RawScreen;

import org.apache.turbine.util.RunData;

import org.jfree.chart.ChartUtilities;
import org.jfree.chart.JFreeChart;

import java.io.OutputStream;

/**
 * @author buddy
 */
public class Image extends RawScreen
{
    /* (non-Javadoc)
     * @see =
org.apache.turbine.modules.screens.RawScreen#getContentType(org.apache.t
u=
rbine.util.RunData)
     */
    protected String getContentType(RunData data)
    {
        return "image/jpeg";
    }

    /* (non-Javadoc)
     * @see =
org.apache.turbine.modules.screens.RawScreen#doOutput(org.apache.turbine
.=
util.RunData)
     */
    protected void doOutput(RunData data) throws Exception
    {
        JFreeChart   chart =3D (JFreeChart) =
data.getSession().getAttribute("chart");
        OutputStream out =3D data.getResponse().getOutputStream();

        ChartUtilities.writeChartAsJPEG(out, chart, 800, 400);
        out.flush();
    }
}

I have build the chart inside my action and put it into the users =
Session. You could do that using
data.getUser().setTemp("image"),JFreeChart) also.
Then I have setup the screen like this. Now I can reference the screen =
in my image tags

&lt;img src=3D"$link.setPage("mrtg,Image.vm")" border=3D"0"/&gt;

kind regards=20

J=FCrgen Hoffmann


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