Apache ActiveMQ ™ -- Delay and Schedule Message Delivery

Features > Message Features > Delay and Schedule Message Delivery

ActiveMQ from version 5.4 has an optional persistent scheduler built into the ActiveMQ message broker. It is enabled by setting the broker schedulerSupport attribute to true in the Xml Configuration.
An ActiveMQ client can take advantage of a delayed delivery by using the following message properties:

Check your Message Properties

The message property scheduledJobIdis reserved for use by the Job Scheduler. If this property is set before sending, the message will be sent immediately and not scheduled. Also, after a scheduled message is received, the property scheduledJobId will be set on the received message so keep this in mind if using something like a Camel Route which might automatically copy properties over when re-sending a message.

Property name

type

description

AMQ_SCHEDULED_DELAY

long

The time in milliseconds that a message will wait before being scheduled to be delivered by the broker

AMQ_SCHEDULED_PERIOD

long

The time in milliseconds to wait after the start time to wait before scheduling the message again

AMQ_SCHEDULED_REPEAT

int

The number of times to repeat scheduling a message for delivery

AMQ_SCHEDULED_CRON

String

Use a Cron entry to set the schedule

For the connivence of Java JMS clients - there's an interface with the property names used for scheduling at org.apache.activemq.ScheduledMessage.

For example, to have a message scheduled for delivery in 60 seconds - you would need to set the AMQ_SCHEDULED_DELAY property:

    MessageProducer producer = session.createProducer(destination);
    TextMessage message = session.createTextMessage("test msg");
    long time = 60 * 1000;
    message.setLongProperty(ScheduledMessage.AMQ\_SCHEDULED\_DELAY, time);
    producer.send(message);

You can set a message to wait with an initial delay, and the repeat delivery 10 times, waiting 10 seconds between each re-delivery:

    MessageProducer producer = session.createProducer(destination);
    TextMessage message = session.createTextMessage("test msg");
    long delay = 30 * 1000;
    long period = 10 * 1000;
    int repeat = 9;
    message.setLongProperty(ScheduledMessage.AMQ\_SCHEDULED\_DELAY, delay);
    message.setLongProperty(ScheduledMessage.AMQ\_SCHEDULED\_PERIOD, period);
    message.setIntProperty(ScheduledMessage.AMQ\_SCHEDULED\_REPEAT, repeat);
    producer.send(message);

You can also use CRON to schedule a message, for example, if you want a message scheduled to be delivered every hour, you would need to set the CRON entry to be - 0 - e.g.

    MessageProducer producer = session.createProducer(destination);
    TextMessage message = session.createTextMessage("test msg");
    message.setStringProperty(ScheduledMessage.AMQ\_SCHEDULED\_CRON, "0 * * * *");
    producer.send(message);

CRON scheduling takes priority over using message delay - however, if a repeat and period is set with a CRON entry, the ActiveMQ scheduler will schedule delivery of the message for every time the CRON entry fires. Easier to explain with an example. Supposing that you want a message to be delivered 10 times, with a one second delay between each message - and you wanted this to happen every hour - you'd do this:

    MessageProducer producer = session.createProducer(destination);
    TextMessage message = session.createTextMessage("test msg");
    message.setStringProperty(ScheduledMessage.AMQ\_SCHEDULED\_CRON, "0 * * * *");
    message.setLongProperty(ScheduledMessage.AMQ\_SCHEDULED\_DELAY, 1000);
    message.setLongProperty(ScheduledMessage.AMQ\_SCHEDULED\_PERIOD, 1000);
    message.setIntProperty(ScheduledMessage.AMQ\_SCHEDULED\_REPEAT, 9);
    producer.send(message);