ireport with struts2

[sathya rajavel]

Here Arraylist contains value but the datasource returns null.please please help me

public String printPDF() {
log.info("===========PDF Printing===============");
ArrayList<OperRepDTO> printpdf=new ArrayList<OperRepDTO>();
log.info(operRepList.size());
printpdf.addAll(operRepList);
log.info(printpdf.size());
return SUCCESS;

<action name="printOperReport" class="OperRepAction" method="printPDF">
<result name="success" type="jasper">
<param name="location">/WEB-INF/CFS .jasper</param>
<param name="dataSource">printpdf</param>
<param name="format">PDF</param>
</result>
</action>