There are two processes in IDOC processing one is INBOUND PROCESS( IDOC coming to the system and its handling at various stages)  and the other is OUTBOUND PROCESS( IDOC is send to other system  . Separate ABAP programs are written for these 2 processes and different configuration settings are required for each one .Depending upon the trigeering mechanism different programming approaches are used.OUTBOUND PROGRAMS handle the IDOC creation and INBOUND PROGRAMS handle the inbound IDOC and the data trasfer from the IDOC to the database tables.

 

 

NEED FOR ABAP PROGRAMMING arises if

1)New IDOC was created

   Depending upon the triggering mechanism i.e change pointer,message control

   etc the programming technique changes and the type of process.

2)Existing IDOC was extended

   User Exits are used to populate data in new segments added and to read them 

   back.

3)To enhance an exsiting process.

   User Exits are used . 

The basic structure of all outbound programs is same. The CONTROL

record which is of TYPE EDIDC has to be filled. It contains important fields like

IDOCTP      IDOC type

MESTYP    Message Type

RCVPRN    Recieving Partner (Destination) 

RCVPRT    Partner Type (it is LS i.e Logical System) 

 

The DATA RECORD internal table which is of TYPE EDIDD has to be filled

in the same order as there are segments in the IDOC definition.

It has 2 important fields which are to be filled ,these are

SEGNAM  Name of the segment

SEGDATA Data in the segment and can be upto 1000 bytes.This field

                is corresponds to each data segment in the IDOC.

e.g.

DATA INT_EDIDD LIKE EDIDD OCCURS 0 WITH HEADER LINE.

DATA W_SEGDATA LIKE zsegment "custom segment zsegment

       

       INT_EDIDD-SEGNAM = 'ZSEGMENT' 

       W_SEGDATA-field1 = value    "taken from some table

       W_SEGDATA-field2 = value    "taken from some table

       INT_EDIDD-SEGDATA = W_SEGDATA

       APPEND INT_EDIDD

This will fill the data record corresponding to the segment ZSEGMENT . For all

segments the sam steps will be repeated until all the data corresponding to all the

segments in the idoc is filled in the internal table of type EDIDD.

      There is only one control record and can be multile data records in the idoc

structure.

   

Which data is to be extracted from the tables to be filled in EDIDD type internal table is determined in standalone programs from the objects which are specified in the selection screen and from the object key passed to the function module in case of message control and is taken from BDCP table in case of change pointers using function modules "CHANGE_POINTERS_READ"

      In case of stand alone programs and function modules based on change pointers method the function module "MASTER_IDOC_DISTRIBUTE" is used to send the IDOC to ALE layer for distribution ,in case of message control it is handled automatically by the RSNASTED program invoked by the message control.                     

 Outbound programs are used in outbound process to genearte IDOCs . There

purpose is to extract the data from the tables and to fill the IDOC data records

and the control record in the IDOC and pass ito the ALE layer for distribution to the recieving system .

 Depending upon the triggering mechanism (how and when the outbound program will be started different techniques and interface is used for outbound program.

 

1)Message control

 Application like PO(purchase order) creation use this technique , where the output type is linked to the application(Message control is a configurable cross application component which can be set in IMG .Such programs are created in the form of function modules and linked to the output type which is linked to the apllication.These have predefined interfaces.

application document is passed to the function module whcig will read the data from the table depending upon the key passed(NAST structure) and fill the IDOC segemnts with the application data.The control record is also passed to the function module but is not fully filled, the rmaining fields are filled and the control is passed back to the calling program which is RSNASTED and is invoked by the

message control to process ALE and EDI output types and this program on recieving the IDOC data will create the physical IDOC in the system.

The parameteers passed to the function module are

IMPORTING PARAMETERS

 OBJECT LIKE NAST

  It contains documents key.

 CONTROL_RECORD_IN  LIKE EDIDC

  It contains the partailly filled control record

EXPORETING PARAMETER

 OBJECT_TYPE 

 CONTROL_RECORD_OUT LIKE EDIDC

TABLES 

 INT_EDID LIKE EDIDD

 The internal table used to fill the data records in the same order as they exists in 

 the IDOC.

 

 The important parameters that should be filled in the custom function module are

 CONTROL_RECORD_OUT and  INT_EDIDD .The OBJK field of the structue NAST contains the key of the apllication document.