ABAP_to_the_Future

Creating Enhancements 6.2
Figure 6.7 Adding New Global Variables
If you want to go to extremes, you could even replace the standard functions with
your own custom logic. An example of this is shown in Listing 6.1.
CALL FUNCTION 'Z_TOTALLY_DIFFERENT_FUNCTION'
EXPORTING real_input_parameter = real_input_parameter
new_input_paramater = new_input_paramater
IMPORTING real_output_parameter = real_output_parameter
new_output_paramater = new_output_paramater.
RETURN.
Listing 6.1 Replacing Standard Functions with Custom Logic
You could do the same with calls to FORM routines, but it has to be stressed that
this is a last resort. If you do this sort of thing, then you often get the clone problem—in
other words, fixes and enhancements to standard SAP code won’t apply
to the code you are now using.
6.2.2 Object-Oriented Programming
The example discussed thus far only addresses the world of procedural programming,
because the bulk of standard SAP programs are written that way. However,
in reality, you want all new programs to be object-oriented—so it’s important to
understand the same concepts in standard classes. In regard to adding extra
parameters to existing methods in standard SAP classes, the procedure is exactly
the same as it is for the function modules discussed in Section 6.2.1. The result
looks like Figure 6.8.
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