Querying the XI Message Header (SAP Library - Enabling Application-to-Application Processes)

Querying the XI Message Header

Use

Using this protocol you can query the fields of the message header after a proxy call.

Integration

You can also query the fields of the message header during a mapping or by using technical context objects in the Integration Directory. See also: Container Object (message mappings), Java Mapping, XSLT Mapping.

Features

Using the Protocol Depending on the Call Situation

Proxy Call	Readable Message Header
Asynchronous proxy call at sender	Message header of request message
Synchronous proxy call at sender	Message header of response message
Synchronous/asynchronous proxy call at receiver	Message header of request message

Fields in Message Header

The GET_HEADER_FIELD method returns the value of a field in the message header as a string. There is a constant in the IF_WSPROTOCOL_XI_HEADER interface for each readable field of the message header.

Accessing Message Header Fields by Using Constants

Constant	Meaning
MESSAGE_CLASS	Classification of message. Possible values: · ApplicationMessage: Asynchronous or synchronous request message · ApplicationResponse: Response to request message · SystemAck, ApplicationAck, SystemError, ApplicationError: Acknowledgments
VERSION_MAJOR	XI message protocol version. Example: For the XI 3.0 message protocol VERSION_MAJOR = 3 and VERSION_MINOR = 0.
VERSION_MINOR
PROCESSING_MODE	The mode of a message can be synchronous or asynchronous. Correspondingly, these constants can have the value synchronous or asynchronous.
MESSAGE_ID	The message ID. It can change during communication: Response messages get a new message ID. If new messages result from a message (the message is copied at multiple receivers), the new messages get new message IDs.
REF_TO_MESSAGE_ID	The ID of a referenced message that belongs semantically to this message. For example, a response message uses this field to note which request message it belongs to.
CONVERSATION_ID	This field is not mandatory in the message. It enables an ID to be used to group messages that belong together. This field is not intended to be used for message serialization and has nothing to do with the serialization context (see context object QueueId).
TIME_SENT	Time stamp specifying when the message was sent by the sender. The format of the time stamp is as follows: YYYY-MM-DDTHH:MM:SSZ The letter ‘T’ separates the date from the time, which is generally specified in UTC. If it is a local time, the closing ‘Z’ is omitted.
INTERFACE	Name of the sender interface.
INTERFACE_NAMESPACE	Namespace of the sender interface.
SENDER_PARTY	Communication party that sent the message.
SENDER_PARTY_AGENCY	Issuing agency for the message sender.
SENDER_PARTY_SCHEME	Identification scheme used by the sender.
SENDER_SERVICE	Service on the sender side that sent the message. For example, the name of a business system.
RECEIVER_PARTY	Communication party to receive the message.
RECEIVER_PARTY_AGENCY	Issuing agency for the message receiver.
RECEIVER_PARTY_SCHEME	Identification scheme used by the receiver.
RECEIVER_SERVICE	Service on the receiver side that receives the message. For example, the name of a business system.
QUALITY_OF_SERVICE	Specifies the quality of service used to process the message. Possible values are BestEffort, ExactlyOnce, or ExactlyOnceInOrder.
QUEUE_ID	Only relevant for QUALITY_OF_SERVICE = ”ExactlyOnceInOrder”. The value in this field corresponds to the serialization context that a sender uses to bundle related asynchronous messages (see also: ABAP runtime, Java proxy runtime).

Note

The following message header fields are only relevant for MessageClass=”ApplicationMessage” and ProcessingMode=”asynchronous”(see above). They can have the Boolean value true or false. See also: Acknowledgments.

Fields of the Message Header for Acknowledgments

Constant	Meaning
SYSTEM_ACK_REQUESTED	If the value of this field is true, the sender requested a positive system acknowledgment.
SYSTEM_ERROR_ACK_REQUESTED	If the value of this field is true, the sender requested a negative system acknowledgment.
APPLICATION_ACK_REQUESTED	If the value of this field is true, the sender requested a positive application acknowledgment.
APPLICATION_ERROR_ACK_REQUESTD	If the value of this field is true, the sender requested a negative application acknowledgment.

Example

In the following example, the IF_WSPROTOCOL_XI_HEADER protocol is used to access the MESSAGE_CLASS field in the message header of the response message at the receiver.

DATA: interface           TYPE REF TO co_sxidag_fsa_query,
      request             TYPE sxidag_fsa_query_mt,
      response            TYPE sxidag_fsa_response_mt,
      xi_header_protocol  TYPE REF TO if_wsprotocol_xi_header,
      xi_header_value     TYPE string.

* create instance
CREATE OBJECT interface

* fill request data
request-flight_seat_availability_query-flight_id-airline_id = 'LH'.

TRY.

* get xi_header protocol
xi_header_protocol ?= interface->get_protocol( if_wsprotocol=>xi_header ).

*   call client proxy
    CALL METHOD interface->execute_synchronous
      EXPORTING
        output = request
      IMPORTING
        input  = response.

* get header field
xi_header_value = xi_header_protocol->get_header_field( if_wsprotocol_xi_header=>message_class ).

CATCH cx_ai_system_fault .
CATCH cx_ai_application_fault .

ENDTRY.