On 5/7/07, Banana Man <[EMAIL PROTECTED]> wrote:
Hi All,
Hi Banana Man :)
I am looking for some advice on using the broker for a pipeline of components (http://activemq.apache.org/camel/pipes-and-filters.html). A couple of pre-requisites of the pipeline are: 1) the processing components should not have any knowledge of their position in the pipeline so that additional processing components could be easily added and existing ones removed 2) all of the processing components in the pipeline should be optional depending on message type and content
That all sounds good so far
3) all messages into the pipeline and from processing components within the pipeline should be sent to a single queue.
FWIW its often useful to use a separate queue for each step in a pipeline; if nothing else it just makes it easier to monitor and manage the system. e.g. if one particular step of a pipeline is not running, or is blocked, you can then easily see by watching the relative queue depths
The Broker should then direct the message to the correct single physical destination based on message content (and from there picked up by a processing component).
Sounds good. A single content based route would do the trick.... http://activemq.apache.org/camel/content-based-router.html
I have got as far as thinking that Filtered Composite Destinations look like a good bet. I read that it is not possible to forward to a virtual destination from a virtual destination so I am a bit concerned about how many rules might fire against the filter destination selectors. Is it possible to force a best match on only one filter destination because I want a single 'message in' to trigger only a single 'message out'. Might this work be more appropriately put in a dedicated rules engine/broker?
Yeah, Camel sounds like just the thing for the routing rules engine. ActiveMQ is great at dealing with individual destinations (whether physical or virtual) but as soon as complex routing requirements are needed, like smart content based routing or whatever, using Camel is a more flexible & powerful option. -- James ------- http://macstrac.blogspot.com/
