Get list element for chart

[dpriya.pratheep]

 

I need to create a chart. I am getting parameter from java .

 

My java code

 

public static List randomData() {

     List   listOfCostSales  = new ArrayList();

       listOfCostSales.add(new CostSales(10.2,1));

       listOfCostSales.add(new CostSales(20.2,2));

       listOfCostSales.add(new CostSales(30.2,3));

       listOfCostSales.add(new CostSales(40.2,4));

   return listOfCostSales;

}

 

parameters.put("listOfCostSales", randomData());

 

jasperPrint = JasperFillManager.fillReport(jasperReport,parameters,dataSource);

 

Then In Ireport I created a chart . In main dataset I created a parameter listOfCostSales as list and cost and month. And created a subdataset Chartdata with listOfCostSales, sale, month.

 

In chart data 

Connection/DataSource Expression, I used Use connection expression from the drop down and set value 

new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($P{listOfCostSales})

 

Parameters Map Expression

$P{REPORT_PARAMETERS_MAP}

 

Parameters 

cost  $P{cost} and month $P{month}

 

I don't know what is wrong with my code. I can't access elements of list. I am getting null key ..

 

For testing Printed month and cost by drag droping. I am getting null

 

Please help me .I am struggling with this for last two week. Almost googled most of the sites and failed to find out the answer.