Advanced Queuing - Oracle

Converting Messages
Figure 18–3 AQ Message Conversion
Advanced Queuing
Message
AQ Property
AQ Payload
Transformation
Function
Transformation
Function
For outbound propagation, after dequeuing a message from an AQ queue, the
gateway agent constructs an internal message by mapping the AQ message
properties of the AQ message to the AQ message properties of the internal message
and converting the AQ payload to an object of the canonical type.
For inbound propagation, after receiving an internal message from a non-Oracle
driver, the gateway agent converts the canonical message to the AQ payload and
then enqueues a message with that payload and the internal AQ message
properties.
The agent can directly enqueue and dequeue messages with a payload of RAW or
SYS.MGW_BASIC_MSG_T to and from AQ queues. The agent provides automatic
mapping between the two payload types and the canonical type. For a payload type
other than RAW or SYS.MGW_BASIC_MSG_T type, a user-supplied transformation
must be provided for conversion between the AQ payload type and the canonical
type.
In general, for outbound propagation, the AQ payload type or output of a
user-supplied transformation must be either RAW or SYS.MGW_BASIC_MSG_T. For
inbound propagation, the AQ payload or input type of a user-supplied
transformation must be either RAW or SYS.MGW_BASIC_MSG_T.
Converting RAW AQ Payload Types
For outbound propagation, the following rules apply:
18-30 Oracle9i Application Developer’s Guide - Advanced Queuing
Messaging Gateway
Message
AQ Property
Canonical Type
Outbound
Propagation
Inbound
Propagation