Typing is a powerful way of creating programs that are easily maintainable, easy to read and understand.
User defined types are created generally in a top include are are introduced with the 'TYPES' keyword. A type statement defines the characteristics of a variable:
- Code: Select all
Types: Uint type i, " Integer
UChar type c, " Char
UKnnr type Kunnr, " Customer code
UVkrg type VkOrg, " Sales Org
UVtWg type VtWeg, " DC
USprt type Spart, " Division
UVrsg type Versg, " Stats group,
UVsBd type Vsbed, " Ship conditions
UdWrk type dWerk, " Del plant
UKtgd type Ktgrd, " Account Assignment
UZtrm type Zterm, " Payment terms,
UAknt type Akont, " Recon account
UNatt type Natxt, " Text message
UFleN type FileName, " File name
*
Begin of Upload_Record, " Inbound data
Kunnr type UKnnr, " Customer code
Vkorg type UVkrg, " Sales Organisation
Vtweg type UVtwg, " Distribution channel
Spart type USprt, " Division
Blank type Uchar, " Blank column
Versg type UVrsg, " Customer Stats Group
VsBed type UVsbd, " Shipping Conditions
Vwerk type UdWrk, " Delivering Plant
Ktgrd type UKtgd, " Account Assignment Group
ZTerm type UzTrm, " Payment Terms
Akont type UAknt, " Reconciliation Account
End of Upload_Record,
*
Begin of Results_Record.
Include type Upload_Record.
Types: Text type UNatt, " BDC Error message
End of Results_Record,
*
Upload_Table type standard table of Upload_Record
Initial size 0,
Error_Table type standard table of Results_Record
Initial size 0.
*
As can be seen in the example above, types can be used to construct simple data types, structures, tables and so forth.
Once a type has been defined, it can be used to declare variables through out the program, including both parameter and form variables:
- Code: Select all
Form Write_Error_File using pu_infile type UFleN
t_error_list type Error_Table.
*
Data: t_Outtab type Upload_Table,
w_Outtab type Upload_Record,
w_Results type Results_Record,
w_Outfile type FileName, " Output file
w_Sfile type string,
w_Max_Lines type UInt, " Progress indication
w_Cur_Line type UInt,
w_Msg type UNatt.
This then provides an additional level of code checking because the parameters to the form are typed and it prevents you from passing any old parameter to the form.
Types can be made system wide by incorporating the data definitions into the ABAP dictionary using transaction SE11.
Also, note that I am also redefining SAP dictionary types. Why should I do this ??
One of the main reasons is maintainability.
Within the data dictionary, if a data element is changed, the change propagates through every program that references that data type - as expected if you are using a data dictionary.
In the same manner, by redefining Data dictionary types and then using that user defined type throughout the program, should the type need to be changed for some reason, then it only needs to be changed in one place.
Consider this subroutine:
- Code: Select all
Form Get_Data using pu_file type FileName
t_Data type Upload_Table.
*
Field-Symbols: <f_Fields>.
*
Data: w_FileName type String,
w_Msg type Natxt.
*
Concatenate 'Uploading '(012)
pu_File
into w_Msg
separated by ' '.
Perform Show_Progress using w_Msg 0 0 0.
*
Move pu_file to w_FileName.
Zap t_Data.
Call Function 'GUI_UPLOAD'
Exporting
Filename = w_FileName
Filetype = 'ASC'
Has_Field_Separator = 'X'
Tables
Data_Tab = t_Data
Exceptions
File_Open_Error = 1
File_Read_Error = 2
No_Batch = 3
Gui_Refuse_Filetransfer = 4
Invalid_Type = 5
No_Authority = 6
Unknown_Error = 7
Bad_Data_Format = 8
Header_Not_Allowed = 9
Separator_Not_Allowed = 10
Header_Too_Long = 11
Unknown_Dp_Error = 12
Access_Denied = 13
Dp_Out_Of_Memory = 14
Disk_Full = 15
Dp_Timeout = 16
Others = 17.
If sy-subrc <> 0.
Message E000 with 'Data could not be loaded'(002).
Zap t_Data.
Else.
*
* Remove blank records....
*
Loop at t_Data Assigning <f_Fields>.
If <F_Fields> = ''.
Delete t_data.
EndIf.
EndLoop.
EndIf.
EndForm.
All it does is to load a file from a presentation server. Using the definition of Upload table above, it will upload a file consisting of 11 fields in the correct manner.
However, change the definition of Upload_Record to:
- Code: Select all
Types: Begin of Upload_Record, " Inbound data
Lifnr type ULfnr, " Vendor code
Bukrs type UBkrs, " Company code
Ktokk type UKtkk, " Vendor Account Group
Akont type UAknt, " Recon Account
Zuawa type UZuawa, " Sort key
Zterm type UZtrm, " payment terms
RepRf type URpRf, " Double entry check
Zwels type UZwels, " Payment methods
D(10) type c, " Unused date
End of Upload_Record,
Then without any change to the code a file containing Vendor information is uploaded. How do I implement this type of code ? By modularising my code and using includes.
