Question Events

Question

Hi All,
Can anyone please tell me the process that happens behind the following code.
*& Report  ZMY_TEST_PROGRAM
REPORT  ZMY_TEST_PROGRAM.
TABLES : KNA1,
         MARA.
SELECTION-SCREEN :BEGIN OF BLOCK SC1 WITH FRAME TITLE TEXT-001.
PARAMETERS : RD1 RADIOBUTTON GROUP RD1 DEFAULT 'X' USER-COMMAND ONLI,
             RD2 RADIOBUTTON GROUP RD1.
SELECTION-SCREEN END OF BLOCK SC1.
data : itab type standard table of mara initial size 10 with header line.
write 'i am fine'.
start-of-selection.
select * from mara into table itab where matnr = '0000001000'.
loop at itab.
write :/ itab-matnr.
endloop.
top-of-page.
write 'this is the header'.
start-of-selection.
select * from mara into table itab where matnr = '0000001001'.
loop at itab.
write :/ itab-matnr.
endloop.
In the above code the write statement "i am fine" falls under which event.
TOP-OF-PAGE is the output event.so how is the control going back to the Start-of-selection once it encounters the write statement.ie.if a write statement is encountered control goes to TOP_OF-PAGE.so how is it able to go back to Start-of-selection
Also how is the ABAP processor able to process both the Start-of-selection events.
i am able to get the output of all the write statements.
so can anyone tell me how the ABAP processor does that work internally.

Answer 1

Hi,
flow of events
load of program
INITIALIZATION. Before the selection screen is displayed.
AT SELECTION-SCREEN OUTPUT. Before painting the screen.
AT SELECTION-SCREEN. Used for validations..
START-OF-SELECTION. When pressed execute button in the selection-screen. If no selection-screen then executes automatically
END-OF-SELECTION. Generally used in the logical database. But in normal reporting triggers after start-of-selection. and is the last event triggered before displaying the report.
AT USER-COMMAND. when user presses button in the list. then this event is triggered
AT LINE-SELECTION. when double clicked on the list.
TOP-OF-PAGE. when first write statement is triggered in the program.
END-OF-PAGE. triggered at the end of the page..
In whatever order u give events flow in the above order  processor checks and processes them accordingly
write statement "i am fine" falls under start-of-selection event.
a start-of-selection event is automatically inserted before write statement
Regards