ABAP_to_the_Future

8
Business Object Processing Framework (BOPF)
between this and the actual action vali dation is a bit blurry. This method is
called twice when an action is processed. First, it’s called just before a validation
is performed to see if an action can be executed. Then, it’s called again just
before the EXECUTE method. Naturally, you get the same set of keys each time,
so only objects that are going to have the action performed on them have an
action validation processed. This method is optional.
왘 EXECUTE
This is the important—that is, not optional—method. It calls the corresponding
action method of your monster model. The signature of the method contains
READ and MODIFY objects for getting and changing any BOPF data, a generic data
object coming in to store any user input parameters, and an error message
object plus a table of failed keys that you can send out (Figure 8.22).
Figure 8.22 Action EXECUTE Method Signature
The actual coding is pretty much the same as the validation and is shown in Listing
8.16. The full code is shown here just to make it clear what’s happening; normally,
you would identify any duplicate code between different classes and
encapsulate it in a utility method.
There are several parts to Listing 8.16. First, you get the data in the header row of
the monster on which the action is to be performed. You use this to get an
instance of the monster model via the factory method of the monster class.
Then, you have to transform the generic data reference object, which is sent to
you by BOPF. This object contains the values of the import parameters you need
to send to the model. Change this to an actual structured variable, and then you
can call the real action method of the model, HOWL_AT_THE_MOON.
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