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The Qpid 0.7 release introduces Last Value Queues (LVQs) into the Java Messaging Broker. The LVQ implementation in the Java Broker provides a superset of the behaviour of the LVQ in the C++ Broker. It is hoped that later revisions of the C++ Broker will adopt the same enhanced semantics.

Note: from version 0.18, the master copy of this documentation is in the AMQP Messaging Broker Java Book.

LVQ Semantics

In an LVQ messages in the queue are be "replaced" by newer messages having the same value for some specified header. An example of an LVQ might be where a queue representing prices on a stock exchange: when you first consume from the queue you get the latest quote for each stock, and then as new prices come in you are sent only these updates.

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