On 7/10/07, James Strachan <[EMAIL PROTECTED]> wrote:
On 7/9/07, happyAMQ <[EMAIL PROTECTED]> wrote:
>
> This sounds ideal. Can you point me to some docs on how to write a plugin?
Here's some documentation...
http://activemq.apache.org/interceptors.html
http://activemq.apache.org/developing-plugins.html
its probably easiest to look at the code for some existing plugins to
get the idea.
I think this will be a useful addition; do you fancy contributing your
plugin to the project?
http://activemq.apache.org/contributing.html
> Would I be using the same JMX method to delete the destinations in this
> plugin?
You could do; though a BrokerPlugin has access to the real broker...
http://activemq.apache.org/maven/activemq-core/apidocs/org/apache/activemq/broker/Broker.html
so you can tinker directly with whatever you like.
Note that its the getDestinationMap() you'll be using on the base
Region interface to introspect the available Destination objects, to
get the DestinatioStatistics (to check for empty queues with no
consumers).
You probably wanna keep a cache in your plugin; for each destination
cache the enqueue counts for empty destinations with no consumers. In
pseudocode...
Whoops - dunno what happened there, I hit send before I'd finished :)
So this is the pseudocode I was thinking really is...
onTimer() {
for (Destination d) {
if (d.destinationStats.messages == 0 && d.destinationStats.consumers == 0) {
enqueueCount = cache.get(d);
if (enqueueCount != null && enqueueCount ==
d.destinationStats.enqueueCount) {
// no activity within a timeout period so lets delete
removeDestination(d);
}
else {
cache.put(d, enqueueCount);
}
}
}
removeDestination(d) {
// lets clean up our cache
cache.remove(d);
super.removeDestination(d)
}
i.e. we want a timer to fire to detect the empty destinations with no
consumers; then if in the subsequent timer period, no messages have
been dispatched and we still have no consumers, then zap the
destination.
--
James
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http://macstrac.blogspot.com/
