This topic describes the types of request-reply messages
that can be exchanged across the WebSphere® MQ
link.
Request-reply exchanges can be:
- Point-to-point messages.
- Queue type reply-to destination.
- Topic type reply-to destination.
- Publication messages.
- Queue type reply-to destination.
- Topic type reply-to destination.
Queue type reply messages (replies sent to a queue-type destination)
cross the WebSphere MQ
link automatically in the same way as point-to-point request messages.
Topic type replies cross the WebSphere MQ
link through the publish/subscribe bridge and are of two varieties:
- Permanent reply-to topics. For a reply message published to a
permanent topic to cross between a WebSphere Application
Server and a WebSphere MQ
network, the administrator must first define an appropriate topic
mapping (defining the topic name and direction) on the publish/subscribe
bridge associated with the WebSphere MQ
link.
- Temporary topic replies. A temporary topic reply message is automatically
routed between a WebSphere Application
Server and a WebSphere MQ
network by the publish/subscribe bridge. This is because the temporary
topic name is assigned at runtime and so a topic mapping cannot be
defined. The exception to this is that only temporary topic replies
to publication messages are supported (that is, point-to-point request
messages with temporary topic reply destinations are not supported).
Note: for
temporary topic reply messages to be routed from the service integration
bus back to WebSphere MQ
through the publish/subscribe bridge, you must configure the broker
stream queue of the mapping on which the request message is sent.
This field will already be specified for bi-directional topic mappings.
While it is not a mandatory field for "From MQ" topic mappings, it
must be completed if you want temporary topic reply messages to be
routed.