Encode/Decode64 PDF File

I have a need to mainly encode64 a PDF document and equally decode an incoming encoded string back to a PDF document.

I have seen several examples where this can be easily done using Java mail API however I cannot figure out how to feed a step with the PDF filename. I have never coded with Java so some of the concepts and getting it to work within ETL is new for me.

I would really appreciate some insight and assistance!

Thanks
Ray