ABAP_to_the_Future

Using BOPF to Write a DYNPRO-Style Program 8.2
and Section 8.2.5, you’ll look at elements of BOPF that are analogous to the initial
screen on which you enter yo ur monster number and click Display or Change.
This encompasses tasks such as checking whether the monster record already
exists, whether the current user is author ized to view or change it, and whether
the record is locked by another user. Next, you’ll look at the BOPF equivalents of
PBO (process before output) processing (what the program does before the data is
presented to the user) in Section 8.2.5 and Section 8.2.6. The tasks in question are
filling out certain fields based on the va lues of others and disabling certain user
commands in certain circumstances. Natu rally, the section ends with the BOPF
equivalents of PAI (process after input) in Section 8.2.7, Section 8.2.8, Section
8.2.9, and Section 8.2.10. Tasks here involve checking user input to make sure
the data is consistent, acting upon comm ands the user has invoked, saving the
record to the database, and creating change documents to track what fields the
user has changed.
8.2.1 Creating Model Classes
This is a good time to prepare yourself to be puzzled. In the next section, you’ll
see how to code the existence check for a BOPF object. You probably know that
this requires about two lines of code in the way you’ve always done things (it’s a
simple SQL query). So when you first see the equivalent BOPF code, which goes
on for pages, it’s easy to decide that BOPF is overcomplicated, ridiculous, or in
the too-hard basket—and switch off and walk away. Try and keep an open mind
until you understand how this all works, because only then can you truly make an
informed decision as to whether BOPF speeds up or slow s down application
development.
Note
Although there’s a lot of detail presented in the upcoming discussion (so that you can
understand what’s going on), Section 8.3. 2 will talk about wrapping mundane boiler
plate tasks in reusable classes with simple interfaces so that you never have to worry
about such details again. This is in fact exactly what SAP itself does internally.
Now, have I scared you enough? Yes? Good! In that case, it’s time to look at how
to start coding a BOPF model class.
You’re going to create class ZCL_MONSTER_MODEL to hold the routines you’ll be
using to manipulate your BOPF monster. As you’ll see shortly, you need instances
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