[Building Sakai] Trying to add charts to the gradebook tool

[Jose Morell]

Hi list,

I'm trying to add charts to the gradebook tool.

I'm using JFreeChart for charts generation.

I have tried to develop this feature by three ways, but none of them seems
to work.

First, I have tried to add the charts with the charCreator library, for
JFreeChart and JSF, but ever appears this exception:

09:58:49,432 ERROR ApplicationDispatcher.java:719 [Chartlet]:719 -
El Servlet.service() para servlet Chartlet lanzó una excepción
java.lang.RuntimeException: Unsupported chart type
at net.sf.jsfcomp.chartcreator.utils.ChartUtils.createChartWithType(Unknown
Source)
at net.sf.jsfcomp.chartcreator.Chartlet.doGet(Unknown Source)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)


Second, I have tried to add the charts only with JFreeChart, and using the
classes ServletUtilities and DisplayChart, but no image charts appears when
I call the servlet:

<img src="/servlet/DisplayChart?filename=<%=filename%>"/>

With a valid filename = jfreechart-3756240288614625342.jpeg


Third, I have tried to add the charts with Ajax4jsf, the same way sitestats
do it, but I get this exception when I add the necessary filters to the
web.xml file:

12:28:11,450  WARN ErrorReporter.java:269 ErrorReporter:269 - Bug Report
bug-id:
bd2064ab-4b3b-4012-9101-47152d2f8ded user:
887219fe-2ad5-4998-925a-40a9c7eaa571 usage-session:
fa6ab436-c430-4736-8e8c-99eaf6cf6f7a time: Apr 6, 2009 12:28:11 user
comment: null stack trace
org.sakaiproject.portal.api.PortalHandlerException:
java.lang.NullPointerException
    at
org.sakaiproject.portal.charon.SkinnableCharonPortal.doGet(SkinnableCharonPortal.java:767)
caused by: java.lang.NullPointerException
at
org.sakaiproject.tool.impl.ActiveToolComponent$MyActiveTool.forward(ActiveToolComponent.java:485)


Any idea about how can I do this?


Regards.


Jose Morell Rama
SETIVAL S.L.
http://www.setival.com/
jose.morell at setival.com
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