Do Not reinvent the wheel how many times have we heard this.... But do we really tend to use the term re-usability.
Well being into multiple implementation projects one thing that always exists is Legacy System and so is Data Transfer or Data upload.....
As we all know LSMW is one of the best tool provided by SAP for data migration but at times it becomes a compulsion to write a conversion program
Thanks to Thomas For the input had forgot to mention LSMW
Here is a snapshot what I did to have a generic template for upload programs.
First I jotted what is common.
File Upload either from presentation server or application server
Second F4 help for file selection.
Third was type of process determination whether it is a BDC or BAPI.....
Fourth was the output of processed records with appropriate messages.
With All this in Place I created a template program.... Well I could have created a Class but.... You can innovate 
Selection Screen Select File name.
Radio Button 2 Fore Ground and Application Server.
For F4 on File selection
This for presentation server
CALL METHOD cl_gui_frontend_services=>file_open_dialog
EXPORTING
window_title = window_title
CHANGING
file_table = i_file
rc = lc_return
EXCEPTIONS
file_open_dialog_failed = 1
cntl_error = 2
error_no_gui = 3
OTHERS = 5.
This is for application server.
CALL FUNCTION '/SAPDMC/LSM_F4_SERVER_FILE'
IMPORTING
serverfile = file_path
EXCEPTIONS
canceled_by_user = 1
OTHERS = 2.
Declared a Type and Table for Error Output
TYPES: BEGIN OF gs_output,
KEY1 TYPE c LENGTH 25,
KEY2 TYPE c LENGTH 25,
RECNO TYPE i,
msg TYPE c LENGTH 125,
END OF gs_output.
Created a BLANK Perform for processing the uploaded file.
Created a Date Conversion perform just in case.
FORM update_date USING p_date TYPE char10
CHANGING c_date TYPE sy-datum.
CLEAR c_date.
CONCATENATE p_date+6(4)
p_date+3(2)
p_date(2)
INTO c_date.
ENDFORM. " UPDATE_DATE
Perform for BDC Append.
*&---------------------------------------------------------------------*
*& Form build_bdc_table
*&---------------------------------------------------------------------*
FORM BUILD_BDC_TABLE USING P_SCREEN TYPE C P_FIELD TYPE C P_VALUE TYPE C.
CLEAR BDCDATA.
IF P_SCREEN = 'X'.
BDCDATA-DYNBEGIN = 'X'.
BDCDATA-PROGRAM = P_FIELD.
BDCDATA-DYNPRO = P_VALUE.
ELSE.
BDCDATA-FNAM = P_FIELD.
BDCDATA-FVAL = P_VALUE.
ENDIF.
APPEND BDCDATA.
ENDFORM. " build_bdc_table
Created Perform's for error handling.
BAPI Error Handling
READ TABLE git_return INTO lwa_ret WHERE type = 'E'.
IF sy-subrc IS INITIAL
MESSAGE ID lwa_ret-id
TYPE lwa_ret-type
NUMBER lwa_ret-number
WITH lwa_ret-message_v1 lwa_ret-message_v2 lwa_ret-message_v3 lwa_ret-message_v4
INTO lwa_out-message.
CALL FUNCTION 'BAPI_TRANSACTION_ROLLBACK'.
ELSE.
MOVE : gwa_table-po_number TO lwa_out-key2,
'Success' TO lwa_out-message.
CALL FUNCTION 'BAPI_TRANSACTION_COMMIT'
EXPORTING
wait = 'X'.
WAIT UP TO 1 SECONDS.
ENDIF.
APPEND lwa_out TO git_out.
BDC Error Handling.
Here I_MSG table is the BDCMSGCOLL which we pass in CALL Transaction.
DATA V_MSG(255) TYPE C.
READ TABLE I_MSG WITH KEY MSGTYP = 'E'.
IF SY-SUBRC = 0.
CALL FUNCTION 'FORMAT_MESSAGE'
EXPORTING
ID = I_MSG-MSGID
LANG = 'E'
NO = I_MSG-MSGNR
V1 = I_MSG-MSGV1
V2 = I_MSG-MSGV2
V3 = I_MSG-MSGV3
V4 = I_MSG-MSGV4
IMPORTING
MSG = V_MSG
ENDIF.
Finally you can output the ERROR table with the processed status.
And use this template in all projects irrespective of the call.
I hope it helps to streamline things.
Any inputs are WELCOME ! ! ! !