On 28 Sep 2005, at 15:25, David Black wrote:
Hi,
I'm wondering does ServiceMix, or more to the point JBI, support a
publish
subscribe type service? What I mean by this is: a service notifying
one or
more clients of some events the clients are interested in over
time. Its not
clear to me looking at the JBI 1.0 spec and at the ServiceMix docs
that this
is supported - but maybe I'm way wrong here :)
When I look at the 4 MEPs, I see:
One-Way
Reliable One-Way
Request-Response
Request-Optional Response
I don't see e.g. Request-Multiple Responses ...
Any help much appreciated
So from WSDL's perspective (and JBI follows the logical WSDL model),
you only see these basic MEPs. For topic notifications, some node in
the network does a one-to-many as an internal feature of its service
(rather like a BPEL engine might generate lots of different
invocations on many services over time as a response to a single
inbound message). However each message sent to a consumer is still a
regular MEP - e.g. a JBI InOnly.
e.g. consider JMS. Each interactions with the JMS broker itself is an
InOnly, its the JMS broker itself which performs the fan out (sending
many InOnly exchanges to different services).
So a MEP is from the perspective of 2 clients only, not many clients.
ServiceMix supports publish & subscribe routing, which allows one-to-
many routing of a JBI components output to many endpoints (whereas
the normal is just 1-1 in JBI).
http://servicemix.org/Publish+and+Subscribe+Routing
In general WS-Notification is the WS/WSDL version of JMS pub/sub; you
interact with a NotificationBroker as a service using an InOnly /
InOut and it does the fan out for you. So a full pub/sub system using
WS protocols still sticks to the core MEPs.
Did that help explain it?
James
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