Java udf for deliveryd date

Hi

I need some help on the writing java udf in PI . or it an be done in graphical mapping .I need to map the latest line item schedule delivery date from idoc source field  to target expected completion date

for example here is the source and target 

Source                                                                      Target
E1EDP2          0.99999                                           Controldetails

EDATU      --------->-                                               completiondate 1.1

       EDATU 08/20/2013
       EDATU  09/20/2013
       EDATU  10/05-2013 ------>                              completiondate              

       EDATu  09/02/2013

Thanks for your help

MK