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#include "qpid/client/QueueOptions.h"

    QueueOptions qo;
    qo.setSizePolicy(RING,0,1000);

    session.queueDeclare(arg::queue=queue, arg::arguments=qo);

Changing the Queue ordering Behaviors (FIFO/LVQ)

The default ordering in a queue in Qpid is FIFO. However additional ordering semantics can be used namely LVQ (Last Value Queue). Last Value Queue is define as follows.

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#include "qpid/client/QueueOptions.h"

    QueueOptions qo;
    qo.setOrdering(LVQ);

    session.queueDeclare(arg::queue=queue, arg::arguments=qo);

    .....
    string key;
    qo.getLVQKey(key);

    ....
    for each message, set the into application headers before transfer
    message.getHeaders().setString(key,"RHT");
    

Notes:

• Messages that are dequeued and the re-queued will have the following exceptions. a.) if a new message has been queued with the same key, the re-queue from the consumer, will combine these two messages. b.) If an update happens for a message of the same key, after the re-queue, it will not update the re-queued message. This is done to protect a client from being able to adversely manipulate the queue.
• Acquire: When a message is acquired from the queue, no matter it's position, it will behave the same as a dequeue
• LVQ does not support durable messages. If the queue or messages are declared durable on an LVQ, the durability will be ignored.

Setting additional behaviors - Optimistic Consume

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