how to pass a report parameter to DataSource?

[2002 JI Open Discussion]

By: Jan Kroulik - honzak123

how to pass a report parameter to DataSource?

2003-06-19 03:27

Hi,

 

I want to have in my subreport a parameter like "Select * from TABLE where ID=$P{ID}" and use it in MyDataSource object. I can't use directly a database connection, because I need to preprocess the result. The problem is that I don't know how to read the parameter from my report and pass it to the MyDataSource.

 

I have tried to use scriptlet and read report parameters in method beforeReportInit(), but it's too late. Jasper report reads data form the DataSource even before it invokes this method.

 

Do you have any idea?

 

thanks

 

 

 

 

By: Giulio Toffoli - gt78

RE: how to pass a report parameter to DataSource?

2003-06-19 05:42

You must have YourDataSource instance before call the fill method of JR. This means that you should adapt your query outside JR when JR engine is not started yet.

 

If you cannot do this, the only solution is "filter" at report generation time your records using bands printWhen expressions or similars.

 

Giulio

 

 

 

 

 

By: Jan Kroulik - honzak123

RE: how to pass a report parameter to DataSource?

2003-06-19 07:24

printWhen expressions or anything else at report generation time can't help me. I need to add extra atributes (columns) to the result.

 

I can of course adapt MyDataSource instance before calling the fill method and when creating MyDataSource instance in DataSource expression. But I will have many reports and SQL queries and I wish to store each query in it's jasper report XML, not separatly.