Here is where I need to get the value:
BEGIN_METHOD ZZMMCHECKMATERIAL CHANGING CONTAINER.
DATA: INMATNR TYPE BAPIMATALL-MATERIAL,
INPLANT TYPE WERKS_D,
EVENTNAME type SWETYPECOU-event.
SWC_GET_ELEMENT CONTAINER 'NewMaterial' INMATNR.
SWC_GET_ELEMENT CONTAINER 'NewPlant' INPLANT.
SWC_GET_ELEMENT CONTAINER 'eventName' EVENTNAME.
CALL FUNCTION 'ZZMM_CHECK_MATERIAL'
EXPORTING
MATNR = INMATNR
EVENTNAME = EVENTNAME
WERKS = INPLANT
EXCEPTIONS
OTHERS = 01.
CASE SY-SUBRC.
WHEN 0. " OK
WHEN OTHERS. " to be implemented
ENDCASE.
END_METHOD.