Outbound/Inbound Trigger Prog.?
I know the Selection Prog.(IDoc_Outbound_<IDoctype>) in Outbound direction and Posting Prog.(IDoc_Inbound_<IDoctype>) in Inbound direction, then,
1-What is Outbound Trigger Program, Does ABAPers writes it? One Prog. name as example pls.!
2-1-What is Inbound Trigger Program, Does ABAPers writes it? One Prog. name as example pls.!
It depends on business case:
Case 1: A customer wants a order acknowledgment for his order, another wants a invoice in EDI formats. In this case you will enable IDoc output through output determination in VA01 and VF01 transactions, you will assign ORDERS, INVOIC message types. The triggering function module would be EDI_PROCESSING
Case 2: A business wants to distribute its material data from its main ERP system where all materials are maintained to non SAP warehouse management systems, price cataloging systems, all of which require some part of material master. For this you will enable ALE, create distribution model with the other systems as receivers, generate partner profiles and activate change pointers, which will trigger MATMAS idoc type whenever important fields on material master are changed via MM* trxns. Here internally you are using MASTER_IDOC_DISTRIBUTE or externally BD10 transaction.
Case 3: You are getting EDI messages from your business partners like payment advices, orders etc. You would need to create IDocs and post the documents to respective transactions like VA01 etc. You are getting the EDI message in a file and map it to ORDERS idoc file on OS. Now you can use EDI_INCOMING data, and if all other configurations like partner profile, inbound process code, message and idoc types are setup, you will be able to post the payment advice or create a sales order
Case 4: You have to post a transaction internally within the system, then you will use IDOC_INBOUND_ASYNCHRONOUS or SYNCHRONOUS.
Case 5: You want to directly trigger SAP from an external system, posting an inbound IDoc, you would need to call IDOC_INBOUND_ASYNCHRONOUS via tRFC connection and ALE
So it all depends on what the business requirement is.