Wildcards

ActiveMQ supports destination wildcards to provide easy support for federated name hierarchies. This concept has been popular in financial market data for some time as a way of organizing events (such as price changes) into hierarchies and to use wildcards for easy subscription of the range of information you're interested in.

For example imagine you are sending price messages from a stock exchange feed. You might use some kind of destination such as

• PRICE.STOCK.NASDAQ.ORCL to publish Oracle Corporation's price on NASDAQ and

• PRICE.STOCK.NYSE.IBM to publish IBM's price on the New York Stock Exchange

A subscriber could then use exact destinations to subscribe to exactly the prices it requires. Or it could use wildcards to define hierarchical pattern matches to the destinations to subscribe from.

Composite Destinations

ActiveMQ supports composite destinations that allow a single virtual JMS Destination to be used to represent a collection of JMS Destinations.

For example you can use composite destinations to send a message to 12 physical queues in one operation. Or send a message to one topic and one queue in one operation.

Composite destinations can also be configured on the broker side, such that messages sent to a single destination by the client will be transparently copied to multiple physical destinations.