ABAP_to_the_Future

8
Business Object Processing Framework (BOPF)
This exception class implements the IF_T100_MESSAGE interface (exception classes
were discussed back in Chapter 7). The BOPF framework likes traditional error
messages and other frameworks (like We b Dynpro) do not, but if our model
sends out a message catering to the lowest common denominator, then the
receiving framework can convert it to whatever it can deal with.
Define the business logic in a method within the monster model (Listing 8.13).
The model is passed the header data, examines it for consistency, and throws an
exception if it does not like what it sees.
METHOD validate_monster_header.
IF is_header_values-hat_size GT 0 AND
is_header_values-no_of_heads EQ 0.
RAISE EXCEPTION TYPE zcx_monster_exceptions
EXPORTING
textid = zcx_monster_exceptions=>head_hat_disparity.
ENDIF.
ENDMETHOD. "Validate Monster Header
Listing 8.13 Validation Method in Main Monster Model
You now have everything you need to code the EXECUTE method in the BOPF generated
validation class. In Listing 8.14, you do five things:
왘 First, you get the data for the node (header row) that you’re interested in.
왘 Then, you hand that data to the model so that it can throw an exception if
something is amiss. If all is fine, then you move straight to the ENDMETHOD statement,
and you’re done.
왘 Next, if it turns out that there’s an error (the model has thrown an exception),
then you add the key of the failed node to a table of nodes that are failures in
life (ET_FAILED_KEY), and this table is exported from the method.
왘 You then create the EXPORTING message parameter (EO_MESSAGE) by means of a
standard BOPF factory method. You can then add one or many error messages
to it.
왘 Finally, you have to create a very specific type of message object (TYPE REF TO /
bobf/cm_frw_core). You are passing into this message object the error message
that the monster model sent out by means of an exception, plus a whole bunch
of constants and the location of the error. Then, add your message to the
exporting parameter, and you’re done.
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