Listeners

A WebSphere MQ Adapter listener continually monitors a queue for messages. When a message appears on a queue, the listener fetches the message, based on the filter criteria that you selected when you configured the listener. The listener passes the message to the listener notification. Unlike the Put and Get adapter services, you never invoke a listener directly from a service or client. Instead, a listener is a real-time process that you configure, enable, and disable using the IS Administrator.

All the listeners will stop functioning when the package containing the listener node is disabled or when Integration Server shuts down.

All the listeners will start functioning when the package containing the listener node is enabled or when Integration Server restarts.

A Single-Queue Listener listens to a single queue configured in the connection.

A Multi-Queue Listener listens to multiple queues configured in the connection. This substantially reduces the number of listeners that needs to be configured and managed. When a multi-queue listener is configured, the adapter in turn creates a single-queue listener for each queue specified in the connection. In effect, there is one listener node (child) for each queue specified in the connection, and one multi-queue listener node (parent). The parent node manages the life cycle (enable/disable/update/delete) of all its child nodes.

All the child listeners are named after the queue they listen to, prefixed by the multi-queue listener name provided. By default, the child listeners inherit all the properties of the parent listener. Whenever the parent listener properties are changed, all the child listeners of that parent are updated with the changed properties. The child listeners can override the parent listener properties when you set the Inherit Parent Listener's Properties parameter to false in the child listener.