# Exclusive Queues

Exclusive queues are special queues which route all messages to only one 
consumer at a time.

This is useful when you want all messages to be processed serially by the same consumer, 
when a producer does not specify [Message Grouping](message-grouping.md).

An example might be orders sent to an address and you need to consume them 
in the exact same order they were produced.

Obviously exclusive queues have a draw back that you cannot scale out the consumers to 
improve consumption as only one consumer would technically be active. 
Here we advise that you look at message groups first.


## Configuring Exclusive Queues

Exclusive queues can be statically configured using the `exclusive` boolean property:

```xml
<configuration ...>
  <core ...>
    ...
    <address name="foo.bar">
      <multicast>
        <queue name="orders1" exclusive="true"/>
      </multicast>
    </address>
  </core>
</configuration>
```

Specified on creating a Queue by using the CORE api specifying the parameter `exclusive` to `true`. 

Or on auto-create when using the JMS Client by using address parameters when creating the destination used by the consumer.

```java
Queue queue = session.createQueue("my.destination.name?exclusive=true");
Topic topic = session.createTopic("my.destination.name?exclusive=true");
```

Also the default for all queues under and address can be defaulted using the address-setting configuration:

```xml
<address-setting match="lastValueQueue">
   <default-exclusive-queue>true</default-exclusive-queue>
</address-setting>
```

By default, `default-exclusive-queue` is `false`. Address wildcards can be used
to configure exclusive queues for a set of addresses (see [here](wildcard-syntax.md)).


## Example

See `org.apache.activemq.artemis.tests.integration.jms.client.ExclusiveTest`