Listening for queues

To listen queues you only should add the next code fragment using the @MQListener annotation.

In the @MQListener annotation you can set the next properties:

• value: Name of the listening queue, use only when listen for a fixed queue
• concurrency: Number of open connections to listening the queue, applies for fixed and temporary queues.
• connectionFactory: Name of a specific ConnectionFactory Bean, used to create the connections for this consumer.
• queueCustomizer: Name of a specific MQQueueCustomizer Bean, used to customize the listening queue properties before start the consumers.

Listening a fixed queue reactive

@MQListener("DEV.QUEUE.1")
public Mono<Void> process(Message message) throws JMSException {
  String text=((TextMessage)message).getText();
  return doSomething(text);
}

You also can set name from properties to make it dynamic configurable

@MQListener("${commons.jms.input-queue}")
public Mono<Void> process(Message message) throws JMSException {
  String text=((TextMessage)message).getText();
  return doSomething(text);
}

You also can pass specific listener settings like:

@MQListener(value = "${commons.jms.input-queue}", concurrency = "5", maxRetries = "5", connectionFactory = "domainB")
public Mono<Void> process(Message message) throws JMSException {
  String text=((TextMessage)message).getText();
  return doSomething(text);
}

Listening a fixed queue non reactive

In this case the main difference is the return type of the annotated method, in reactive should be Mono<Void> and the method should return the reactive flow resolving a Mono<Void>. In non reactive must be void and in this case no return value is required

@MQListener("DEV.QUEUE.1")
public void process(Message message) throws JMSException {
  String text=((TextMessage)message).getText();
  doSomething(text);
}

Connection Architecture

This sample will listen for a fixed queue named DEV.QUEUE.1, the JMS objects structure will be like this:

The amount of JMSContexts and JMSConsumers is related to the concurrency annotation attribute (see setup), it is based on JMS 2.0. .