Need help using method as a parameter to find a subreport

[meatwad]

The background of this problem is that I have a web application reading report files from a predefined location. The reports, and their subreports, will be stored in jar files. I don't know if this is the best approach but it's the first one I chose. The only way I know of to get at a file inside a jar is by accessing it as an InputStream so that's what I've chosen as the subreport expression type in iReport.

Inside iReport I'm looking for a way to hardcode the name of the subreport but make the class and method it is supplied to a parameter. This allows me to run it both in iReport and from the web app.

Is there a good way to do this or am I barking up the wrong tree?