Customer exits in the inbound function module allow customers to:
Change the way SAP segments are processed, for example, by changing the value of fields
Access the customer segments they added to the SAP IDoc using the IDoc definition tool
The following points should be fulfilled by the customer exits:
Can all the data in SAP segments in the IDoc be read via customer exits?
Can all the customer segments in the IDoc be read via customer exits?
Is a customer exit called every time a segment has been processed?
Does the customer exit support error handling?
Can the exit fill the parameters Workflow_Result, Idoc_Status, and Return_Variables?
Is there a customer exit for serialization?
This is useful if the inbound function module does not support serialization.
If the customer has appended fields to an SAP table, are these fields easily accessible in the exit?
Are the exits long-lived? Customers expect exits to be called with the same meaning in future releases.
Is it easy for the customer to navigate through the data in the exit? For example, to determine which item us currently being processed, and so on.
If the same coding is used for different message types: Can the customer identify which message type is being used?
The Example Program for a Customer Exit shows the implementation of a customer exit.