| ... You can configure this to use whatever naming convention you wish. The following example shows how to make all topics virtual topics. The example below is using the name > to indicate 'match all topics'. You could use this wildcard to apply different virtual topic policies in different hierarchies. ...
<destinationInterceptors>
<virtualDestinationInterceptor>
<virtualDestinations>
<virtualTopic name=">" prefix="VirtualTopicConsumers.*." selectorAware="false"/>
</virtualDestinations>
</virtualDestinationInterceptor>
</destinationInterceptors>
... Note that making a topic virtual does add a small CPU overhead when sending messages to the topic but it is fairly small. ... The following example shows how to set up a <compositeQueue/> element in the XML configuration so that when a message is sent to MY.QUEUE then it is really forwarded to the physical queue FOO and the topic BAR. ...
<destinationInterceptors>
<virtualDestinationInterceptor>
<virtualDestinations>
<compositeQueue name="MY.QUEUE">
<forwardTo>
<queue physicalName="FOO" />
<topic physicalName="BAR" />
</forwardTo>
</compositeQueue>
</virtualDestinations>
</virtualDestinationInterceptor>
</destinationInterceptors>
... By default, subscribers cannot consume messages directly from a composite queue or topic - it is a logical construct only. Given the configuration above, subscribers can only consume messages from FOO and BAR; but not MY.QUEUE. This behaviour can be altered to implement use cases such as watching a queue by sending the same messages to a notification topic (wire tapping), by setting the optionally set forwardOnly attribute to false. ...
<compositeQueue name="IncomingOrders" forwardOnly="false">
<forwardTo>
<topic physicalName="Notifications" />
</forwardTo>
</compositeQueue>
... Messages sent to IncomingOrders will all be copied and forwarded to Notifications, before being placed on the physical IncomingOrders queue for consumption by subscribers. ... The following example shows how a message sent to the virtual destination MY.QUEUE will be forwarded to FOO and BAR if the selectors match ...
<destinationInterceptors> <virtualDestinationInterceptor> <virtualDestinations>
<compositeQueue name="MY.QUEUE">
<forwardTo>
<filteredDestination selector="odd = 'yes'" queue="FOO"/>
<filteredDestination selector="i = 5" topic="BAR"/>
</forwardTo>
</compositeQueue>
</virtualDestinations> </virtualDestinationInterceptor> </destinationInterceptors>
... Avoiding Duplicate Message in a Network of Brokers ... Here is an example of how to do that: ...
<networkConnectors> <networkConnector uri="static://(tcp://localhost:61617)">
<excludedDestinations>
<queue physicalName="Consumer.*.VirtualTopic.>"/>
</excludedDestinations>
</networkConnector> </networkConnectors>
... |
