Abstract: Topics are linked in a publish/subscribe messaging environment. A first topic is linked to at least a second topic, and a message on the first topic is published to subscribers to the first topic. In the same transaction, any reference to the topics linked to the first topic are published in the message to subscribers of the topics linked to the first topic. A tree of topics is defined with topic nodes for each topic. A topic string is provided in a path through the tree of topics to a topic node, wherein the first topic and the at least a second topic have no commonality of topic string.

Abstract: An apparatus for controlling subscriptions comprising: a detector operable to detect to a subscription associated with a wildcard topic string; and an analyzer, responsive to the detection of the subscription associated with a wildcard topic string and a topic string of a topic node matching the wildcard topic string, for analyzing a first attribute of the topic node; and means for determining whether a subscriber associated with the subscription should receive a message associated with the topic string of the topic node.

Abstract: Topics are linked in a publish/subscribe messaging environment. A first topic is linked to at least a second topic, and a message on the first topic is published to subscribers to the first topic. In the same transaction, any reference to the topics linked to the first topic are published in the message to subscribers of the topics linked to the first topic. A tree of topics is defined with topic nodes for each topic. A topic string is provided in a path through the tree of topics to a topic node, wherein the first topic and the at least a second topic have no commonality of topic string.

Abstract: An apparatus for controlling subscriptions comprising: a detector operable to detect to a subscription associated with a wildcard topic string; and an analyzer, responsive to the detection of the subscription associated with a wildcard topic string and a topic string of a topic node matching the wildcard topic string, for analyzing a first attribute of the topic node; and means for determining whether a subscriber associated with the subscription should receive a message associated with the topic string of the topic node.

Abstract: A method of operating a message handling system comprises maintaining queues, receiving messages, placing each message on a queue, running one or more applications which access the queues, detecting the receipt of a message with a predefined flag, and blocking at least one application from accessing the message with the predefined flag. The blocking of at least one application from accessing the message with the predefined flag can be achieved by discarding the message with the predefined flag prior to the message being placed on a queue. In an alternative embodiment, the blocking is achieved by preventing the blocked applications from removing the message from a queue.