How to expand the BOM using ABAP?

在某项目中，根据业务部门提出的需求，需要把BOM展开。通过调用系统提供的FM来实现BOM 展开的函数。以下是实现代码的函数。

FUNCTION Z_BOM_EXPAND.

*"---------------------

*"*"Local Interface:

*" IMPORTING

*" VALUE(MATNR) LIKE MARA-MATNR

*" VALUE(WERKS) LIKE MARC-WERKS OPTIONAL

*" VALUE(CAPID) LIKE TC04-CAPID DEFAULT 'PP01'

*" TABLES

*" STB STRUCTURE STPOX

*" RETURN STRUCTURE BAPIRET2

*"---------------------

IF WERKS IS INITIAL."Added in case external call does not know

WERKS = '3001'.

ENDIF.

IF CAPID IS INITIAL.

CAPID = 'PP01'.

ENDIF.

CALL FUNCTION 'CS_BOM_EXPL_MAT_V2'

EXPORTING

CAPID = CAPID

DATUV = SY-DATUM

MEHRS = 'X'

MTNRV = MATNR

WERKS = WERKS

TABLES

STB = STB

EXCEPTIONS

NO_BOM_FOUND = 1.

IF sy-subrc <> 0.

msg_typ = 'E'.

msg_id = 'Z_EF'.

msg_no = '002'.

msg_v1 = MATNR.

if not msg_typ is initial.

* append error to table RETURN

call function 'BALW_BAPIRETURN_GET2'

exporting

type = msg_typ

cl = msg_id

number = msg_no

par1 = msg_v1

par2 = msg_v2

par3 = msg_v3

par4 = msg_v4

parameter = space

row = space

field = space

importing

return = wa_return_tmp.

append wa_return_tmp to return.

endif.

ENDIF.