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Queue Configuration

The following are example queue configurations.

Declarative:

<queue name="default">
    <max-size>0</max-size>
    <backup-count>1</backup-count>
    <async-backup-count>0</async-backup-count>
    <empty-queue-ttl>-1</empty-queue-ttl>
    <item-listeners>
       <item-listener>
          com.hazelcast.examples.ItemListener
       </item-listener>
    <item-listeners>
</queue>
<queue-store>
    <class-name>com.hazelcast.QueueStoreImpl</class-name>
    <properties>
       <property name="binary">false</property>
       <property name="memory-limit">10000</property>
       <property name="bulk-load">500</property>
    </properties>
</queue-store>

Programmatic:

Config config = new Config();
QueueConfig queueConfig = config.getQueueConfig();
queueConfig.setName( "MyQueue" ).setBackupCount( "1" )
        .setMaxSize( "0" ).setStatisticsEnabled( "true" );
queueConfig.getQueueStoreConfig()
        .setEnabled ( "true" )
        .setClassName( "com.hazelcast.QueueStoreImpl" )
        .setProperty( "binary", "false" );

Queue configuration has the following elements.

  • max-size: Maximum number of items in the Queue.
  • backup-count: Number of synchronous backups. Queue is a non-partitioned data structure, so all entries of a Set resides in one partition. When this parameter is '1', it means there will be 1 backup of that Set in another node in the cluster. When it is '2', 2 nodes will have the backup.
  • async-backup-count: Number of asynchronous backups.
  • empty-queue-ttl: Used to purge unused or empty queues. If you define a value (time in seconds) for this element, then your queue will be destroyed if it stays empty or unused for that time.
  • item-listeners: Lets you add listeners (listener classes) for the queue items. You can also set the attribute include-value to true if you want the item event to contain the item values, and you can set local to true if you want to listen to the items on the local node.
  • queue-store: Includes the queue store factory class name and the properties binary, memory limit and bulk load. Please refer to Queue Persistence.
  • statistics-enabled: If set to true, you can retrieve statistics for this Queue using the method getLocalQueueStats().