Message listener

*.listener binds a JS / TS handler to a queue or topic on the embedded ActiveMQ broker.

• File format. JSON descriptor.
• Synchronizer. ListenerSynchronizer (tenant-isolated).
• Broker. Embedded ActiveMQ.
• Editor. Listeners editor.
• JS / TS API. @aerokit/sdk/messaging - producer side, plus consumer helpers.
• See also. Java @MessageListener - annotation-based alternative for client Java.

File format

{
    "location": "/myproject/listeners/orders.listener",
    "name": "orders-queue",
    "kind": "Q",
    "handler": "myproject/listeners/orders-handler.js",
    "description": "Process incoming orders"
}

Field	Purpose
location	Registry path of the descriptor itself.
name	Queue / topic name on the broker.
kind	Q for queue, T for topic.
handler	Registry path of the JS / TS module that receives each message.
description	Free text.

The handler module is invoked once per message. The message body and headers are available to the handler via the messaging context.

Java alternative - @MessageListener

A client .java class annotated with @MessageListener(name = "orders-queue", kind = QUEUE) is registered without a .listener artefact. See Message listeners for the full annotation surface.

.listener is preferred when the binding should live in the registry and reload without restart. Use the annotation when you want the handler and binding to ship as one Java source.

Tenancy

Listener subscriptions are tenant-isolated - each tenant's reconciled .listener files own their own subscriptions on the broker.