Which PDF API can i use to get a document with dynamic fields?

I have a problem to choose which PDF API can i use to generate a pdf with dynamic fields... I've used jasper report some time ago but the requirements has changed and now i have dynamic fields... It means that in one report i can have "Name, Ph开发者_C百科one, Address" and in another i can have "Name, Address, Age, Phone, Birthday"... I've no how to know which fields im gonna have in the report until the use choose the fields to be impressed... If i try using jasper report and the use dont choose some field im gonna have a big space with blank content...

I were thinking if is there some how to make a loop into jasper... I mean, i get a list of object and into those objects im gonna have another list... SOmeone understood my problem or have some idea about how can i solve it?

You can populate a Velocity template that contains an FO representation of your PDF, populate the dynamic variables, and then turn it into a PDF using an FO Transformer. No Jasper required.

You can look at generating the PDF documents using IText:

http://itextpdf.com/

It's a relatively easy to use API, but will be programming heavy compared to something like Jasper.