to read activity id / activity journal within Action

Hello Experts,

I have a Activity created for Blocking/unblocking(Status) the product-Flat.

On choosing the status 'Blocking' from activity page and saving the Action is triggered - In Action the processing type is Method call, i have implemented the BADI 'EXEC_METHODCALL_PPF' . With in this method a simple update statement to set the status of a product in the ztable to 'blocked' is put.

But for this the Method will have to read the product entered in the activity journal.

My Question is how to read or get the activity id or guid within the action method. So that the product is read and only then can i proceed.

Please give me some direction on how to proceed on this.

Thanks,

Jaya.