60 lines
1.9 KiB
Markdown
60 lines
1.9 KiB
Markdown
# Exclusive Queues
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Exclusive queues are special queues which route all messages to only one
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consumer at a time.
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This is useful when you want all messages to be processed serially by the same consumer,
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when a producer does not specify [Message Grouping](message-grouping.md).
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An example might be orders sent to an address and you need to consume them
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in the exact same order they were produced.
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Obviously exclusive queues have a draw back that you cannot scale out the consumers to
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improve consumption as only one consumer would technically be active.
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Here we advise that you look at message groups first.
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## Configuring Exclusive Queues
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Exclusive queues can be statically configured using the `exclusive` boolean property:
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```xml
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<configuration ...>
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<core ...>
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...
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<address name="foo.bar">
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<multicast>
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<queue name="orders1" exclusive="true"/>
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</multicast>
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</address>
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</core>
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</configuration>
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```
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Specified on creating a Queue by using the CORE api specifying the parameter `exclusive` to `true`.
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Or on auto-create when using the JMS Client by using address parameters when creating the destination used by the consumer.
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```java
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Queue queue = session.createQueue("my.destination.name?exclusive=true");
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Topic topic = session.createTopic("my.destination.name?exclusive=true");
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```
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Also the default for all queues under and address can be defaulted using the address-setting configuration:
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```xml
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<address-setting match="lastValueQueue">
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<default-exclusive-queue>true</default-exclusive-queue>
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</address-setting>
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```
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By default, `default-exclusive-queue` is `false`. Address wildcards can be used
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to configure exclusive queues for a set of addresses (see [here](wildcard-syntax.md)).
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## Example
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See `Exclusive Queue` in [examples](examples.md).
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For additional examples see `org.apache.activemq.artemis.tests.integration.jms.client.ExclusiveTest`
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