How to use the CONVERSION_EXIT_PARVW_INPUT and CONVERSION_EXIT_PARVW_OUTPUT

FUNCTION CONVERSION_EXIT_PARVW_INPUT.
*"----------------------------------------------------------------------
*"Lokale Schnittstelle:
*" IMPORTING
*" INPUT
*" EXPORTING
*" OUTPUT
*"----------------------------------------------------------------------

READ TABLE S WITH KEY SY-LANGU.
IF SY-SUBRC NE 0.
SELECT * FROM TPAUM APPENDING TABLE XTPAUM WHERE SPRAS = SY-LANGU.
SORT XTPAUM BY SPRAS PARVW.
S-SPRAS = SY-LANGU. APPEND S.
ENDIF.

CLEAR OUTPUT.
LOOP AT XTPAUM WHERE SPRAS = SY-LANGU AND PABEZ = INPUT.
OUTPUT = XTPAUM-PARVW.
EXIT.
ENDLOOP.
IF OUTPUT = ' '. OUTPUT = INPUT. ENDIF.

ENDFUNCTION.

FUNCTION CONVERSION_EXIT_PARVW_OUTPUT.
*"----------------------------------------------------------------------
*"Lokale Schnittstelle:
*" IMPORTING
*" INPUT
*" EXPORTING
*" OUTPUT
*"----------------------------------------------------------------------

READ TABLE S WITH KEY SY-LANGU.
IF SY-SUBRC NE 0.
SELECT * FROM TPAUM APPENDING TABLE XTPAUM WHERE SPRAS = SY-LANGU.
SORT XTPAUM BY SPRAS PARVW.
S-SPRAS = SY-LANGU. APPEND S.
ENDIF.

TPAUM_KEY-MANDT = SY-MANDT.
TPAUM_KEY-SPRAS = SY-LANGU.
TPAUM_KEY-PARVW = INPUT.

READ TABLE XTPAUM WITH KEY TPAUM_KEY BINARY SEARCH.
IF SY-SUBRC = 0.
OUTPUT = XTPAUM-PABEZ.
ELSE.
OUTPUT = INPUT.
ENDIF.

ENDFUNCTION.