When processing application events, the ALE Module acts as a server to the SAP application. In this capacity, the ALE Module receives events that the SAP application "pushes", or sends, to the connector. When processing requests, the ALE Module receives business object requests from the integration broker and sends them to the SAP application.
This section documents the following processes:
The init() method opens an RFC connection to the SAP R/3 application through the SAP Gateway. If the connector fails to initialize, it terminates the connection using the terminate() method. The connector terminates by disconnecting from the SAP Gateway.
When processing application events or business object requests, the connector's initialization process does the following:
For more information, see Configuring the ALE module.
Because the connector supports multi-threading, when the ALE Module processes requests from the integration broker, it does not use the module's init() method to create a connection handle. Instead, it uses the Vision connector framework's connection pool of such handles.
The ALE Module's processing of WebSphere business objects for SAP is initiated either through event processing or request processing.
This section describes:
Two RFC-enabled functions in an SAP application initiate all event processing for the ALE Module. The ALE's business object handler for event processing supports the functions idoc_inbound_asynchronous and inbound_idoc_process.
When processing events, this business object handler persistently stores the business objects in an MQSeries queue. The connector maintains the Transaction IDs (TIDs) associated with the RFC call to guarantee that each piece of data is delivered once and only once.
This section describes the following:
Figure 17 illustrates how the ALE Module processes the MQSeries queue.
Figure 17. Business object event processing
Business-object event processing for the ALE Module executes in the following manner:
Each JMS-MQ message represents a single RFC call. Each RFC call can represent one or more business objects associated with a single TID. The connector stores the TID in the message's CorrelationID property, sets the TidStatus to CREATED, and sets the IDocProcessStatus to unknown. The connector uses the message body to store IDoc data.
If the AleUpdateStatus configuration property evaluates to true, the connector updates the status of the IDoc in SAP. If it retrieves a packet of IDocs, it updates the status of all IDocs in the packet. For more information, see "Updating the IDoc Status in SAP".
For more information see, Creating Archive Messages.
The Ale Module uses FIFO (First In, First Out) to maintain the processing order when reading the messages from the Event queue.
A single event message may contain multiple IDocs, each of which represents a business object. As it processes each IDoc in the event message, the connector creates corresponding messages in the Archive queue. The number and types of archive messages depends on the processing status of each IDoc.
For example, assume the connector processes an event message with four
IDocs, each of which it transforms or attempts to transform into a business
object, with the results illustrated in Table 16:
Table 16. Archive Message Creation
Status of IDoc or business object | Resulting Archive Message |
---|---|
Successfully transforms the first IDoc, and posts the business object to the integration broker | Creates an archive message with the same CorrelationID as the event message, and an IDocProcessStatus of success--the message contains the data in the first IDoc |
Fails to transform the second IDoc into a business object |
|
Successfully transforms the third IDoc, and posts the business object to the integration broker | Writes the data from the third IDoc to the message with the IDocProcessStatus of partial |
Successfully transforms the fourth IDoc, but the business object created is not subscribed in the integration broker |
|
The connector handles the event message from the Event queue in either of the following scenarios:
Table 17 describes the structure of the message that the connector
sends to the Event and Archive queues.
Table 17. Structure of JMS-MQ Message for Event and Archive Processing
Property Name | Description |
---|---|
CorrelationId | The JMS message header property--the connector sets the value of this property from the Transaction ID (TID) sent by SAP |
TidStatus | The JMS message header property that maintains the status of the TID |
IDocProcessStatus | The JMS message header property that maintains the status of the IDoc object during event processing |
As the connector processes each IDoc in an event message, it moves the IDoc into a message in the Archive queue. The archive message has the same CorrelationId as the event message. Depending on the processing status of each IDoc, the connector may create up to four different archive messages that correspond to the same event message.
Table 18 describes the possible values for the IDocProcessStatus
property after a single business object's events are moved to the Archive
queue.
Table 18. Archive Queue Values for the IDocProcessStatus Message Property
IDocProcessStatus Property Value | Event Status | Description |
---|---|---|
success | Success | When all IDocs in a single event message process successfully, the corresponding archive message contains all IDocs. In this case, there is a single archive message. |
partial | Success | When some of the IDocs in a single event message fail processing, this archive message contains only the successfully processed IDocs. In this case, there are multiple archive messages. |
unsubscribed | Unsubscribed | When some of the IDocs in a single event message are unsubscribed, this archive message contains all the unsubscribed IDocs. In this case, there are multiple archive messages. |
original | N/A |
|
fail | Fail | When any IDoc in a single event message fails processing, this archive message contains all the IDocs that failed formatting or were not sent successfully to the integration broker. In this case, there are multiple archive messages. |
recovery | Possible failure | When event message processing does not finish properly, that is, the
connector has successfully processed all IDocs in the event message but the
event message has not been moved out of the event queue, the recovery process
does the following:
This situation may occur if the connector dies before it moves the event message out of the event queue. In this case, there are multiple archive messages. |
To cause the connector to update a standard SAP status code after the ALE Module has retrieved an IDoc for event processing, you must:
If AleUpdateStatus evaluates to true, the connector sends the ALEAUD IDoc to SAP with status code information and, optionally, descriptive text. The ALEAUD IDoc calls the IDOC_INPUT_ALEAUD function module. The connector supports sending the following status codes to this function module:
The AleSuccessCode connector-specific configuration property can have a value of 52 or 53. SAP converts this value to 41.
The AleFailureCode connector-specific configuration property can have a value of 68. SAP converts this value to 40.
In both of the cases above, the business integration system does not send further status codes that would indicate further processing.
For information on setting the connector-specific configuration properties that are required to return IDoc status, see:
For information on setting the connector-specific configuration properties that are optional to return IDoc status, see:
The Vision connector framework uses the value of the verb AppSpecificInfo property of the top-level business object to instantiate the ALE request-processing business object handler. The doVerbFor() method in the request-processing business object handler initiates all business object requests.
The business object handler converts the business object data into two tables that represent the IDoc format and its meta-data component, the control record. Once the data is in IDoc format, the business object handler makes an RFC call to the appropriate SAP function module: either idoc_inbound_asynchronous or inbound_idoc_process. Because ALE is asynchronous, the connector does not wait for a return response.
If the TransactionId attribute does not exist, the ALE Module sends the request directly to SAP. If the TransactionId attribute exists, the ALE Module does the following:
Business Object Attribute Name | JMS-MQ Message Property Name | SAP Application |
---|---|---|
TransactionID | CorrelationId |
|
| TransactionID | TID |
Table 20 describes the structure of the JMS-MQSeries message that the
connector gets from the Request queue:
Table 20. Structure of JMS-MQ Message for Request Processing
Property Name | Description |
---|---|
CorrelationId | The connector gets the value of this property from the TransactionId attribute of the request business object sent by the integration broker. If the TransactionId attribute contains no value, the connector constructs a value for this property from:BOName + BOKeyAttributes + TimeStampThe timestamp includes hour, minute, second, and millisecond of the system time. For example:sapCustomerMasterAttr1keyAttr2key150713882 |
TransactionId | TID received from SAP. The value of this property serves as the unique identifier of the MQSeries message |
TidStatus | Status of the transaction |