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Using JMS priority field

jef_2802
jef_2802 Member Posts: 23
edited Sep 27, 2011 6:12AM in Java Message Service (JMS)
Hi,

How to use Jms priority header field in JMS applications ?
How is it implemented by MOM ?
How will a consumer use this value ? If messages with different priorities are in a queue, what will be the result if a consuming application makes a simple call to get or receive or is listening on the queue (with MessageListener) ?
Is the result depending on the JMS provider implementation ?

Thanks
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Answers

  • EJP
    EJP Member Posts: 32,943 Gold Crown
    edited Sep 26, 2011 4:44PM
    It isn't documented?
  • Nigel Deakin-Oracle
    Nigel Deakin-Oracle Member Posts: 115
    edited Sep 27, 2011 5:41AM
    To set the priority when sending a message, use the following message on MessageProducer:

    void send(Message message, int deliveryMode, int priority, long timeToLive)
    Sends a message to the destination, specifying delivery mode, priority, and time to live.

    Alternatively you can set the default priority for a MessageProducer by calling
    setPriority(int defaultPriority)

    Note that the following method on Message is for a different purpose and hould not be used
    void setJMSPriority(int priority)

    The JMS 1.1 specification contains the following explanation of message priority.

    3.4.10 JMSPriority

    JMS defines a ten-level priority value, with 0 as the lowest priority and 9 as the
    highest. In addition, clients should consider priorities 0-4 as gradations of
    normal priority and priorities 5-9 as gradations of expedited priority.

    JMS does not require that a provider strictly implement priority ordering of
    messages; however, it should do its best to deliver expedited messages ahead
    of normal messages.

    4.4.10.2 Order of Message Sends

    • Messages of higher priority may jump ahead of previous lower-priority messages.
  • EJP
    EJP Member Posts: 32,943 Gold Crown
    Well exactly. @OP so what's the mystery again?
This discussion has been closed.