How does isForPrompting works?

Question

I'm new to Jasper reports.

Can anyone help me explaining how isForPrompting works? I have a Java program as below:

---

jasperReport = JasperCompileManager.compileReport("sample_report.jrxml");

// filling report with data from data source

jasperPrint = JasperFillManager.fillReport(jasperReport,jasperParameter, connection);

// exporting process

JasperExportManager.exportReportToPdfFile(jasperPrint,"sample_report.pdf");

---

The JRXML file contains a parameter with "parameterDscription" and with attribute "isForPrompting" set to true.

However while running my program, It never says or prompt for any run time parameter. When I click on report generated by Java program (that's a PDF file) it doesn't promt for any parameter.

I don't know what I'm missing here? I would like to know how this parameter can be used, specially how the program will throw a prompt to end user?

Thanks, A~P