Hi Aziz,
You can use a mix of standard function and a small UDF to arrive at the logic. Something like below:
For Input date(Begda) in my screenshot, you can use the date field from source (delivery date). this can be in any format but make sure you change the source field date format in standard Date functions, DateAfter or DateBefore.
Instead of add Function above, you have to create a UDF which would add certain days to the current date.
Use calendar class and standard cal.add(Calendar.DATE, days); where days is the number of days.
If you need further help with the UDF, please let me know.
It was not clear from your post on what you plan to populate if the above condition is met so I have left it here. You can build your logic on top of the logic above. 
Hope it helps!
Ambrish
Message was edited by: Ambrish Mishra