ABAP various ways to Exit processing Blocks
No matter which programming language you are working with, at the end of the day
your job revolves around manipulating its processing block to achieve the
desired results. One of them is exiting it.
In this post, I wanted to talk about various ways you could exit an ABAP
processing block.
But first,
What is a Processing Block?
Modularization unit of an ABAP program that
cannot be split or nested. Processing blocks are
- Procedures like subroutines or
methods,
- Dialog modules declared for
screens, and
- Event blocks like reporting events
such as load-of-program, start-of-selection, etc.
To summarise,
Each non-declared statement in an ABAP program is part of a processing block.
Now, coming back to the point of the post.
Below are the different ABAP statements that you can use to exit the
processing block.
RETURN:
Syntax: RETURN.
Example:
Features:
- This statement ends the current processing block immediately.
- Can be used at any point in the processing block.
- The statement ends the block irrespective of the statement block or
control structure it is used inside.
In Other words,
Even if you use the statement
RETURN inside loops, it will end the whole processing
block
that contains the loop, not just the loop block.
Things to Note:
- You cannot exit the load-of-program event block using
RETURN.
- If you use RETURN to
exit start-of-selection, No further reporting events are
triggered.
Instead, the list processor is called
directly.
My Opinion:
- This is by far the best way to exit procedures.
EXIT:
Syntax: EXIT.
Example:
Features:
- If used outside a loop block, the statement
immediately terminates the current processing block.
- If used inside a loop block, the statement terminates
it.
Things to Note:
- You cannot exit the load-of-program event block using EXIT.
- If you use the EXIT to exit
the start-of-selection event, no further reporting events
are triggered. Instead, the list
processor is called directly.
My Opinion:
- The EXIT statement should only be used to terminate
loop blocks prematurely.
CHECK:
Syntax: CHECK log_exp.
Example:
Features:
- If used outside a loop and the log_exp is false, the statement immediately terminates the
current processing block.
- If used inside
a loop and the log_exp is
false, the statement skips the current loop pass and
moves on to the
next loop pass.
Things to Note:
- You cannot exit the load-of-program using CHECK.
My Opinion:
- The CHECK statement should be used either at the start of the
processing block as a
guard clause or inside loop block to skip loop passes based on a
certain condition.
STOP:
Syntax: STOP.
Example:
Features:
- The STOP statement is only to be used in
executable programs and in the following event blocks:
at selection-screen (without additions),
start-of-selection.
These event blocks are exited
using STOP and the runtime environment triggers the event
end-of-selection.
- Using STOP at other places will lead to
non-catchable exceptions and runtime errors:
stop_no_report - Executed outside the process for an executable
program.
stop_within_called_dynpro - Executed during the process for a screen
and
therefore outside the permitted
events.
My Opinion:
Do not use the STOP statement unless absolutely necessary
and there are no other options to
achieve the desired results.
In Conclusion,
In ABAP, There are different options available
for program-driven exiting of a processing block
with each having its own
features.
However from a robustness point of view RETURN statement
is the best option, the second
choice being CHECK as a guard clause at
the start of the block.
I hope you liked the post and use this
information while in your day-to-day work.
