With release 7.50 we introduced the system class
CL_ABAP_CORRESPONDING that allows you to do
dynamically what you can do with the
CORRESPONDING operator statically.
There were two gaps in CL_ABAP_CORRESPONDING that are closed now.
Usage of a Lookup Table
The CORRESPONDING operator has two variants, one
base form and one with a
lookup table. The latter constructs an internal table by looking up another table and using the lines found there as sources of the corresponding assignment:
TYPES:
BEGIN OF line,
value TYPE i,
comment TYPE string,
END OF line,
itab1 type STANDARD TABLE OF line WITH EMPTY KEY,
itab2 TYPE HASHED TABLE OF line WITH UNIQUE KEY value.
DATA(itab1) = VALUE itab1( for i = 1 UNTIL i >= 10 ( value = i ) ).
DATA(itab2) = VALUE itab2( ( value = 2 comment = `...` )
( value = 3 comment = `...` )
( value = 5 comment = `...` )
( value = 8 comment = `...` ) ).
itab1 = CORRESPONDING itab1( itab1 FROM itab2 USING value = value ).
In this simple example, the lines of itab1 that are available in itab2 are taken over to itab1.
In release 7.50, this opportunity was missing for CL_ABAP_CORRESPONDING but is made available in release 7.51:
TYPES:
BEGIN OF line,
value TYPE i,
comment TYPE string,
END OF line,
itab1 TYPE STANDARD TABLE OF line WITH EMPTY KEY,
itab2 TYPE HASHED TABLE OF line WITH UNIQUE KEY value.
DATA(itab1) = VALUE itab1( FOR i = 1 UNTIL i >= 10 ( value = i ) ).
DATA(itab2) = VALUE itab2( ( value = 2 comment = `...` )
( value = 3 comment = `...` )
( value = 5 comment = `...` )
( value = 8 comment = `...` ) ).
DATA(mapping_tab) = VALUE cl_abap_corresponding=>mapping_table(
( level = 0 kind = 4 srcname = 'PRIMARY_KEY' )
( level = 0 kind = 5 srcname = 'VALUE' dstname = 'VALUE' ) ).
cl_abap_corresponding=>create_using(
destination = itab1
using = itab2
mapping = mapping_tab
)->execute_using( EXPORTING using = itab2
CHANGING destination = itab1 ).
This example does the same using CL_ABAP_CORRESPONDING as the example for CORRESPONDING above. In real life you use variables instead of literals of course.
For more information see
CL_ABAP_CORRESPONDING - Lookup Table.
Reflexive Assignments
In release 7.50 source and target must not be the same when using CL_ABAP_CORRESPONDING otherwise the runtime error CORRESPONDING_SELF can occur.
See the respective
example for release 7.50, where the reflexive assignments with CL_ABAP_CORRESPONDING are prepared but not possible yet.
Now see the same
example for release 7.51. Reflexive assignments with CL_ABAP_CORRESPONDING are possible now.
cl_abap_corresponding=>create(
source = str1
destination = str1
mapping = VALUE cl_abap_corresponding=>mapping_table(
( level = 0 kind = 1 srcname = 'a4' dstname = 'a1' )
( level = 0 kind = 1 srcname = 'a3' dstname = 'a2' )
( level = 0 kind = 1 srcname = 'a1' dstname = 'a3' )
( level = 0 kind = 1 srcname = 'a2' dstname = 'a4' ) )
)->execute( EXPORTING source = str1
CHANGING destination = str1 ).
