I am using pentaho report engine 3.6 to embed reports in my web application.
I create a report in report designer and then use the .prpt file to show the report in my application.
I want to show the selected parameters in report header.
Some parameters are multivalue lists.
To show this list as a comma separated string I created a open formula using function 'csvtext' which converts the multivalue list to a string.

This works fine in report designer.
But not in the web application.

How do I handle the openFormula in java code so that it will show the selected parameter values in my report header?

I can show the selected values for Single value parameters.

Can anybody suggest what is the right way to do it?