ABAP_to_the_Future

Using BOPF to Write a DYNPRO-Style Program 8.2
DELETE ct_key WHERE key = ls_monster_header-key.
ENDMETHOD. "Check
METHOD are_values_derivation_relevant.
IF is_header_values-no_of_heads > 0.
rf_relevant = abap_true.
ELSE.
rf_relevant = abap_false.
ENDIF.
ENDMETHOD.
Listing 8.10 Coding the CHECK Method for a Determination
The EXECUTE Method
The EXECUTE method is the method that actually does the determination (i.e.,
changes some values based on others), provided the CHECK_DELTA and CHECK
methods allow it to be run. From a tech nical point of view, the important thing
about this method is that not only do you get an imported (via the method parameters)
object, READ, which allows you to read the current values, but also another
imported object, MODIFY, which lets you modify these values.
In Listing 8.11, you can see that there are three simple steps to executing a determination.
First, you use the imported object READ to get the values from the database
for a given monster (or many monsters at once, given that a table of the keys
is being passed in). Then, create an instance of your model class and perform the
monster-specific logic (i.e., logic that would be the same no matter what framework
you were using) to fill up the tr ansient fields. Finall y, use the imported
object MODIFY to pass back the completed combined structure to BOPF.
METHOD /bobf/if_frw_determination~execute.
* Local Variables
DATA: lt_monster_header TYPE ztt_monster_header,
ls_monster_header LIKE LINE OF lt_monster_header,
lo_monster_model TYPE REF TO zcl_monster_model.
* Clear Exporting Parameters
CLEAR: eo_message,
et_failed_key.
* Get the persistent (database) values
io_read->retrieve(
EXPORTING iv_node = zif_monster_c=>sc_node-monster_header
it_key = it_key
315