BAdI is Business Add-In, and it should take the place from the user- exits (trx: SE18, SE19)
BADI - This is a program enhancement technique. SAP provides BADI openings in the standard programs. You need to search for the suitable BADI as ur requirement and then do the coding and plug in the program. A BADI is a Business Add-in - one of SAP's methods of implementing a user-exit or change to standard SAP code. BADI's are ABAP object based changes instead of the more common subroutines/function modules.
To implement BADI, Follow the below steps to find out what all BADI's are called when you press any button in any transaction.
1) Goto se24 (Display class cl_exithandler)
2) Double click on the method GET_INSTANCE.
3) Put a break point at Line no.25 (CASE sy-subrc). Now
4) Execute SAP standard transaction
5) Press the required button for which you need to write an exit logic, the execution will stop at the break point.
6) Check the values of variable 'exit_name', it will give you the BADI name called at that time.
7) This way you will find all the BADIs called on click of any button in any transaction.
