Apache 带有 ActiveMQ 的 Camel JMS：发送具有动态优先级的消息

Question

I am currently implementing a Java messaging system with Apache Camel and ActiveMQ. My goal is to dynamically set the priority of a message based on a few attributes the message has.

I already configured my ActiveMQ as explained here . Then I created the following method that sends a TextMessage :

public void send(BaseMessage baseMessage, int jmsPriority) throws JsonProcessingException {
    Map<String, Object> messageHeaders = new HashMap<>();
    messageHeaders.put(MESSAGING_HEADER_JMS_PRIORITY, jmsPriority);
    messageHeaders.put(MESSAGING_HEADER_TYPE, baseMessage.getClass().getSimpleName());
    String payload = objectMapper.writeValueAsString(baseMessage);
    producerTemplate.sendBodyAndHeaders(payload, messageHeaders);
}

Sending the message perfectly works, and the dynamic type of BaseMessage is properly set to the header of each message. The priority is set as well, but is ignored. The order for the outcoming messages is still FIFO, as queues usually do.

Until now I did not achieve to set the priority of the message dynamically. I do not want to use Apache Camel's Resequencer since I would have to create several new queues only for "sorting". From my point of view ActiveMQ must be able to prioritize and reorder the messages itself.

Any tip is appreciated. Ask me for further details if required.

Answer 1

By default, ActiveMQ disables message priority. This is normal. When doing distributed messaging-- sending messages across servers, prioritization does not practically work out, since the broker can only scan so many messages in the queue for messages of a higher priority before it stats to slow down all traffic for that queue.

Prioritized messages can work well when embedding a broker and using it for task dispatch-- where queue depth generally doesn't exceed the low-thousands.

Updated:

Reminder-- the QOS settings in JMS must be set on the MessageProducer object, and not the message per JMS-spec.

Enable Prioritized Messages