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CEWOLF: ClassCastException DataTag cannot be cast to de.laures.cewolf.taglib.tags.Parameterized

 
Greenhorn
Posts: 2
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Hi All,

I am suffering from this error for lots of times, and after searching all over the internet but without any clues found to solve the problem.

I am using cewolf to draw High-Low charts . when trying to pass parameters from JSP to my DatasetProduer, I got this error:

---------------------------------------------------------------------------------------------------------------------------
HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: de.laures.cewolf.taglib.tags.DataTag cannot be cast to de.laures.cewolf.taglib.tags.Parameterized
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:564)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:431)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:319)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

root cause

java.lang.ClassCastException: de.laures.cewolf.taglib.tags.DataTag cannot be cast to de.laures.cewolf.taglib.tags.Parameterized
de.laures.cewolf.taglib.tags.ParamTag.doEndTag(ParamTag.java:42)
org.apache.jsp.CandleStick2_jsp._jspx_meth_cewolf_005fparam_005f0(CandleStick2_jsp.java:252)
org.apache.jsp.CandleStick2_jsp._jspx_meth_cewolf_005fdata_005f0(CandleStick2_jsp.java:203)
org.apache.jsp.CandleStick2_jsp._jspx_meth_cewolf_005fchart_005f0(CandleStick2_jsp.java:164)
org.apache.jsp.CandleStick2_jsp._jspService(CandleStick2_jsp.java:122)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:389)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:319)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.0 logs.
Apache Tomcat/6.0.0
---------------------------------------------------------------------------------------------------------------------

//* in CandleStick2.jsp */

<%@taglib uri='/WEB-INF/cewolf-1.1.tld' prefix='cewolf' %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB2312">
<title>Insert title here</title>
</head>
<body>
<H1>Page View Statistics</H1>
<HR>

<jsp:useBean id="postproducer" class="com.cck.util.MyChartPostProcessor"/>
<jsp:useBean id="CandleStickProducer1" class="com.cck.dataproducer.CandleStickProducer1"/>
<jsp:useBean id="params" class="com.cck.dataproducer.ParamBean" scope="request"/>
<jsp:setProperty name="params" property="*"/>
<%String symbol = "000001";%>
<cewolf:chart id="CandleStick" title="CandleStick" type="candlestick" xaxislabel="Date/Time">
<cewolf:data>
<cewolf:producer id="CandleStickProducer1" />

<cewolf:param name="symbol" value="<%=symbol%>"></cewolf:param>
</cewolf:data>
<cewolf:chartpostprocessor id="postproducer"/>
</cewolf:chart>
<cewolf:img chartid="CandleStick" renderer="cewolf" width="1024" height="400"/>
</body>
</html>

-----------------------------------------------------------------------------------------------------


/* in CandleStickProducer1 */----------------------------------------------------

public class CandleStickProducer1 implements DatasetProducer, CategoryToolTipGenerator,CategoryItemLinkGenerator, Serializable {

..........................
@Override
public Object produceDataset(Map params) throws DatasetProduceException {
// TODO Auto-generated method stub

...........
String symbol = (String) params.get("symbol");

..............


--------------------------------------------------------------------------------------------

Tomcat: 6
Jre: 6
Cewolf 1.1
Jfreechart: 1.0.13


Any comments will be most appriceated!

Thanks in advance!

Ken






 
Rancher
Posts: 43011
76
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If you check out the tagdocs you'll see that only cewolf:producer can have cewolf:param childs, not cewolf:data. Try something like this:

Also, you can avoid scriptlets by using value="${symbol}" instead of value="<%=symbol%>".
 
ken zeng
Greenhorn
Posts: 2
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HI Ulf,

Thanks very much for your reply, the problem is now solved, it`s really the case as you said.

Ken
 
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