I have been using XSL-FO and FOP Engine to generate PDF documents for required data. This works great, but lately I have seen some limitations in FOP especially when it comes to allowing user to enter text in a html editor which can be transformed to XSL-FO and given to FOP driver.
This brought me to point to ask this large community of well informed individuals about what are possible Open Source or even non open source libraries to generate PDF documents in Java?
BigFaceless has a closed source option for building up a document in Java and transforming it to PDF:
If you want to stick with XSL-FO and are prepared to go the commercial route, I would suggest using RenderX's XEP. I have recently moved to it from FOP 0.2x and found it gets round a lot of FOPs limitations through the use of extensions.
The down side is it costs a bit, but I would suggest you take a look: http://new.renderx.com/tools/xep.html
You could use Docmosis which is free, sits over OpenOffice and Java and can run on just about any platform. It can generate large documents (thanks to OpenOffice) and Docmosis contains some ability to overcome limitations in OpenOffice for very large text blocks and the like. I can't say whether this will solve your issues with user entered content but that shouldn't be a factor in any system as long as you are correctly encoding/escaping XML tokens inside user data when you need to.