How to split a string into 4 strings of equal length in ABAP?

This question sounds trivial, doesn’t it?

I ran into this when developing the new tasklist for the mass maintenance of OData services (see my blog Custom tasklist for OData service mass maintenance).

Since I am calling API’s that do not return the root cause of an error I wrote some code that retrieved the long text of the original error.

The problem was then that I had to call a method to add a T100 message to a log file that required 4 parameters of type CHAR50.

So I had to cut the string into 4 pieces each having the length of 50 characters.

Let’s have a look what would happen if the incoming string has a length of 102 characters.

First approach: CALL FUNCTION ‘SWA_STRING_SPLIT’

First I tried the function module ‘SWA_STRING_SPLIT’ that takes a string and the desired length of the substring as an Input parameter. The split string is returned via the table lt_string_comp.

CALL FUNCTION 'SWA_STRING_SPLIT'
  EXPORTING
     input_string         = lv_longtext     "string to be split
     max_component_length = 50 
   TABLES
     string_components    = lt_string_comp
                .

You then still have the problem to find out the number of table entries and you cannot access the fourth table entry lt_string_comp[ 4 ] if the table has only three entries if the string has a length of 102 characters.

Second Approach: Use substring

The built in function substring has the disadvantage that it throws an error of type cx_sy_range_out_of_bounds if it would reach the statement

DATA(lv3) = substring( val = lv_longtext off = 100 len = 50 ).

in case the string contained in lv_longtext has a length of 102 characters.

DATA: lv_longtext TYPE char200.
...
CATCH /iwfnd/cx_cof INTO DATA(lx_cof).
lv_longtext = lx_cof->get_longtext( ).
TRY.
    DATA(lv1) = substring( val = lv_longtext off = 0 len = 50 ).
    DATA(lv2) = substring( val = lv_longtext off = 50 len = 50 ).
    DATA(lv3) = substring( val = lv_longtext off = 100 len = 50 ).
    DATA(lv4) = substring( val = lv_longtext off = 150 len = 50 ).
  CATCH cx_sy_range_out_of_bounds INTO DATA(lx_too_long).
    WRITE : / lx_too_long->get_text( ).
ENDTRY.

Third Approach: Use old-fashioned ABAP syntax

Though it is not recommended the following code works like a charm. If the string has a length of 102 characters lv7 would contain 2 characters and lv8 would simply be intial.

DATA(lv5) = lv_longtext(50).
DATA(lv6) = lv_longtext+50(50).
DATA(lv7) = lv_longtext+100(50).
DATA(lv8) = lv_longtext+150(50).

Fourth approach: Use cl_message_helper=>set_msg_vars_for_clike

Another option was mentioned by Matthew Billingham as a comment to this blog. By calling the method set_msg_vars_for_clike of class cl_message_helper you get four strings of length 50 characters as well.

This method under the hood uses the old fashioned ABAP syntax

MOVE c200+offset(50) TO sy-msgv2.

as well.

It in addition offers lots of other useful methods as well.

Final approach: Use a structure

The most flexible approach in my opinion (kudos go to my colleagues from the SAP Gateway runtime development team) is using a structure

In the following I move the long text to a structure with 4 fields of length 50 characters each.

As a result error messages longer than 200 characters are truncated but no exception is thrown opposed to using substring.

And it does not make use of out of date ABAP coding style.

Moreover you would be able to define a structure with fields that have different lengths, say 10, 24, 40 and 5 characters. A string moved to this structure would be split approriately without having to look for exceptions whose handling is time consuming and not needed in this case.

TYPES: BEGIN OF ty_longtext,
         msgv1(50),
         msgv2(50),
         msgv3(50),
         msgv4(50),
END OF ty_longtext.
DATA: ls_longtext      TYPE ty_longtext.
...         
CATCH /iwfnd/cx_cof INTO DATA(lx_cof).

ls_longtext = lx_cof->get_longtext( ).

"add a t100 message
if_stctm_task~pr_log->add_t100(
        EXPORTING
            iv_msgty      = 'E'
            iv_msgid      = '/IWFND/COD'
            iv_msgno      = '312'
            iv_msgv1      = CONV #( ls_longtext-msgv1 )
            iv_msgv2      = CONV #( ls_longtext-msgv2 )
            iv_msgv3      = CONV #( ls_longtext-msgv3 )
            iv_msgv4      = CONV #( ls_longtext-msgv4 )
).

Simple test report

If you want to play around I have created the following test report that shows four of the five approaches described above.

*&---------------------------------------------------------------------*
*& Report z_split_string
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT z_split_string.

DATA: lv_teststring TYPE string.
DATA: lv_longtext TYPE char200.

TYPES: BEGIN OF ty_longtext,
         msgv1(50),
         msgv2(50),
         msgv3(50),
         msgv4(50),
       END OF ty_longtext.
DATA: ls_longtext TYPE ty_longtext.

lv_teststring = '0123456789'. "10 characters
lv_teststring = lv_teststring && lv_teststring. "20 characters
lv_teststring = lv_teststring && lv_teststring. "40 characters
lv_teststring = lv_teststring && lv_teststring. "80 characters
lv_teststring = lv_teststring && '0123456789' && '012345678901' . "102 characters

DATA(length) = strlen( lv_teststring ).

lv_longtext = lv_teststring.
ls_longtext = lv_teststring.

TRY.
    DATA(lv1) = substring( val = lv_longtext off = 0 len = 50 ).
    DATA(lv2) = substring( val = lv_longtext off = 50 len = 50 ).
    DATA(lv3) = substring( val = lv_longtext off = 100 len = 50 ).
    DATA(lv4) = substring( val = lv_longtext off = 150 len = 50 ).
  CATCH cx_sy_range_out_of_bounds INTO DATA(lx_too_long).
    data(lv_error_lx_too_long) = lx_too_long->get_text( ).
ENDTRY.

DATA(lv5) = lv_longtext(50).
DATA(lv6) = lv_longtext+50(50).
DATA(lv7) = lv_longtext+100(50).
DATA(lv8) = lv_longtext+150(50).

cl_message_helper=>set_msg_vars_for_clike( lv_longtext ).




data(out) = cl_demo_output=>new( ).

out->write( : data = lv_error_lx_too_long ),
              data = '********************************' ),
              data = 'use of substring' ),
              data = lv1 ),
              data = lv2 ),
              data = lv3 ),
              data = lv4 ),
              data = 'old ABAP syntax' ),
              data = lv5 ),
              data = lv6 ),
              data = lv7 ),
              data = lv8 ),
              data = 'string moved to structure' ),
              data = ls_longtext-msgv1 ),
              data = ls_longtext-msgv2 ),
              data = ls_longtext-msgv3 ),
              data = ls_longtext-msgv4 ),
              data = 'use cl_message_helper' ),
              data = sy-msgv1 ),
              data = sy-msgv2 ),
              data = sy-msgv3 ),
              data = sy-msgv4
              )->display( ).

This Report generates the following Output:

Substring access (offset = 100, length = 50) to a data object of the size 102 exceeds valid boundaries.

********************************

use of substring

01234567890123456789012345678901234567890123456789

01234567890123456789012345678901234567890123456789

Field

Field

old ABAP syntax

01234567890123456789012345678901234567890123456789

01234567890123456789012345678901234567890123456789

01

Field

string moved to structure

01234567890123456789012345678901234567890123456789

01234567890123456789012345678901234567890123456789

01

Field

use cl_message_helper

01234567890123456789012345678901234567890123456789

01234567890123456789012345678901234567890123456789

01

Field