Inbound processing for the ALE pass-through IDoc interface

The adapter supports inbound processing (from the SAP server to the adapter) for the ALE pass-through IDoc interface.

When you are configuring a module for the ALE pass-through interface, you can indicate whether the IDocs are sent as a packet. You make this selection on the Configuration Properties window of the external service wizard. The selection you make is reflected in the application-specific information for the IDoc wrapper business object.

You can also choose to send the IDoc in Flat File format to the end point. You make this selection on the Specify the Configuration Properties for 'object' screen using the Send IDoc in flat file format check box. This feature will only work if the adapter is configured to work with unparsed Control Records where the Parse the IDoc Control Record check box is disabled.

Note: When you use the ALE pass-through IDoc interface, a wrapper business object contains a data stream representing the IDoc. No separate IDoc business object exists for pass-through IDocs.

The following list describes the sequence of processing actions that result from an inbound request using the ALE interface.

The adapter starts event listeners to the SAP server.
Whenever an event occurs in SAP, the event is sent to the adapter by way of the event listeners.
The adapter converts the event into a business object before sending it to the endpoint.

The adapter uses the event recovery mechanism to track and recover events in case of abrupt termination. The event recovery mechanism uses a data source for persisting the event state.

If you have selected split IDocs and SAP is sending packet IDocs, the adapter delivers each IDoc inside the packet as an individual event to the end point. During recovery, the SAP system has to resubmit the whole packet. The adapter only delivers IDocs which have not been delivered in previous attempts from the packet.

Note that the adapter is able to listen to and deliver events from multiple SAP systems using multiple activation specs.

The adapter is also able to deliver events to multiple endpoints. You enable delivery to multiple endpoints by configuring multiple activation specifications that exist in the same module.

If the endpoints subscribe to the same events from the same SAP system, all properties in the individual activation specifications must be identical.
Endpoints that subscribe to different activation specifications receive events that match the criteria for the activation specification.

Define a separate activation specification for each endpoint to which events need to be delivered, except when the adapter delivers events only to those endpoints that are active.

Note: When multiple endpoints subscribe to the same events from the same event store, the adapter assures event delivery to active endpoints only. Any endpoints that are inactive do not receive the event. If there are multiple endpoints and any one endpoint is not active, the message is skipped for that endpoint and the adapter delivers the event only to the active endpoints. If all the endpoints are inactive, the event is rolled back, and the event needs to be resubmitted from SAP.

The following table provides an overview of the differences between the ALE interface and the ALE pass-through IDoc interface for inbound processing.

Table 1. Differences between ALE interface and ALE pass-through interface
Interface	When to use	SplitIDoc = true	SplitIDoc = false	Parsed IDoc = true	Flat File format = true
ALE inbound	This interface converts the raw incoming IDocs to business objects, which are readily consumable by the client at the endpoint.	On receiving the IDoc packet from SAP, the adapter converts the IDocs to business objects, one by one, before sending each one to the endpoint.	On receiving the IDoc packet from SAP, the adapter converts the IDocs in the packet as one business object before sending it to the endpoint.	The incoming IDoc is only partially parsed (the control record of the IDoc is parsed but the data record is not). The client at the endpoint is responsible for parsing the data record.	not applicable
ALE pass-through IDoc	This interface wraps the raw incoming IDoc in a business object before delivering it to the client at the endpoint. The client is responsible for parsing the raw IDoc.	On receiving the IDoc packet from SAP, the adapter wraps each raw IDoc within a business object before sending the objects, one by one, to the endpoint.	On receiving the IDoc packet from SAP, the adapter wraps the raw IDoc packet in a business object before sending it to the endpoint.	Control record of the incoming IDoc is parsed. In case of the packet IDoc, only the first IDoc from the control record will be parsed.	The incoming IDoc would be sent as a HexBinary in Flat File format, where each record (control and data record) is separated with a delimiter.