Chapter 28. Management

A list of deployed core queues can be retrieved using the getQueueNames() method.

Core queues can be created or destroyed using the management operations:

createQueue will fail if the queue already exists while deployQueue will do nothing.

The QueueControl can pause and resume the underlying queue. When a queue is paused, it will receive messages but will not deliver them. When it is resumed, it will begin delivering the queued messages.

Client remote addresses can be retrieved using listRemoteAddresses(). It is also possible to close the connections associated with a remote address using the closeConnectionsForAddress() method.

Alternatively, connection ids can be listed using listConnectionIDs() and all the sessions for a given connection id can be listed using listSessions().

In the case of a server crash, some transactions may require manual intervention when the server restarts. The listPreparedTransactions() method lists the transactions which are in the prepared states (the transactions are represented as opaque Base64 Strings.) To commit or rollback a given prepared transaction, the commitPreparedTransaction() or rollbackPreparedTransaction() method can be used to resolve heuristic transactions. Heuristically completed transactions can be listed using the listHeuristicCommittedTransactions() and listHeuristicRolledBackTransactions methods.

Message counters can be enabled or disabled using the enableMessageCounters() or disableMessageCounters() method. To reset message counters, it is possible to invoke resetAllMessageCounters() and resetAllMessageCounterHistories() methods.

The HornetQServerControl exposes HornetQ server configuration through all its attributes (for example, getVersion() method to retrieve the server's version, and so on.)

Messages can be expired from a queue by using the expireMessages() method. If an expiry address is defined, messages will be sent to it, otherwise they are discarded. The queue's expiry address can be set with the setExpiryAddress() method.

Messages can also be sent to a dead letter address with the sendMessagesToDeadLetterAddress() method. It returns the number of messages which are sent to the dead letter address. If a dead letter address is not defined, message are removed from the queue and discarded. The queue's dead letter address can be set with the setDeadLetterAddress() method.

Messages can also be moved from a queue to another queue by using the moveMessages() method.

Messages can be listed from a queue by using the listMessages() method which returns an array of Map; one Map for each message.

Messages can also be removed from the queue by using the removeMessages() method which returns a boolean for the single message id variant or the number of removed messages for the filter variant. The removeMessages() method takes a filter argument to remove only filtered messages. Setting the filter to an empty string will remove all messages.

The number of messages in a queue is returned by the getMessageCount() method. Alternatively, the countMessages() will return the number of messages in the queue which match a given filter

The message priority can be changed by using the changeMessagesPriority() method which returns a boolean for the single message id variant or the number of updated messages for the filter variant.

Message counters can be listed for a queue with the listMessageCounter() and listMessageCounterHistory() methods (see Section 28.6, “Message Counters”). The message counters can also be reset for a single queue using the resetMessageCounter() method.

The QueueControl exposes core queue settings through its attributes (for example, getFilter() to retrieve the queue's filter if it was created with one, isDurable() to know whether the queue is durable or not, and so on).

The QueueControl can pause and resume the underlying queue. When a queue is paused, it will receive messages but will not deliver them. When it is resumed, it will begin delivering the queued messages.

Acceptors can be started or stopped using the start() or. stop() method on the AcceptorControl class (with the ObjectName org.hornetq:module=Core,type=Acceptor,name="<the acceptor name>" or the resource name core.acceptor.<the address name>). The parameters of the acceptors can be retrieved using the AcceptorControl attributes (see Section 14.1, “Understanding Acceptors”)

Diverts can be started or stopped using the start() or stop() method on the DivertControl class (with the ObjectName org.hornetq:module=Core,type=Divert,name=<the divert name> or the resource name core.divert.<the divert name>). Diverts parameters can be retrieved using the DivertControl attributes (see Chapter 33, Diverting and Splitting Message Flows)

They can be started or stopped using the start() (resp. stop()) method on the BridgeControl class (with the ObjectName org.hornetq:module=Core,type=Bridge,name="<the bridge name>" or the resource name core.bridge.<the bridge name>). Bridges parameters can be retrieved using the BridgeControl attributes (see Chapter 34, Core Bridges)

Broadcast groups can be started or stopped using the start() or stop() method on the BroadcastGroupControl class (with the ObjectName org.hornetq:module=Core,type=BroadcastGroup,name="<the broadcast group name>" or the resource name core.broadcastgroup.<the broadcast group name>). Broadcast groups parameters can be retrieved using the BroadcastGroupControl attributes (see Section 36.2.1, “Broadcast Groups”)

They can be started or stopped using the start() or stop() method on the DiscoveryGroupControl class (with the ObjectName org.hornetq:module=Core,type=DiscoveryGroup,name="<the discovery group name>" or the resource name core.discovery.<the discovery group name>). Discovery groups parameters can be retrieved using the DiscoveryGroupControl attributes (see Section 36.2.2, “Discovery Groups”)

They can be started or stopped using the start() or stop() method on the ClusterConnectionControl class (with the ObjectName org.hornetq:module=Core,type=ClusterConnection,name="<the cluster connection name>" or the resource name core.clusterconnection.<the cluster connection name>). Cluster connections parameters can be retrieved using the ClusterConnectionControl attributes (see Section 36.3.1, “Configuring Cluster Connections”)

Names of the deployed connection factories can be retrieved by the getConnectionFactoryNames() method.

JMS connection factories can be created or destroyed using the createConnectionFactory() methods or destroyConnectionFactory() methods. These connection factories are bound to JNDI so that JMS clients can look them up. If a graphical console is used to create the connection factories, the transport parameters are specified in the text field input as a comma-separated list of key=value (that is, key1=10, key2="value", key3=false). If there are multiple transports defined, you need to enclose the key/value pairs between curly braces. For example {key=10}, {key=20}. In that case, the first key will be associated to the first transport configuration and the second key will be associated to the second transport configuration (see Chapter 14, Configuring the Transport for a list of the transport parameters)

Names of the deployed JMS queues can be retrieved by the getQueueNames() method.

JMS queues can be created or destroyed using the createQueue() methods or destroyQueue() methods. These queues are bound to JNDI so that JMS clients can look them up

Names of the deployed topics can be retrieved by the getTopicNames() method.

JMS topics can be created or destroyed using the createTopic() or destroyTopic() methods. These topics are bound to JNDI so that JMS clients can look them up.

JMS Clients remote addresses can be retrieved using listRemoteAddresses(). It is also possible to close the connections associated with a remote address using the closeConnectionsForAddress() method.

Alternatively, connection ids can be listed using listConnectionIDs() and all the sessions for a given connection id can be listed using listSessions().

The ConnectionFactoryControl exposes JMS ConnectionFactory configuration through its attributes (that is, getConsumerWindowSize() to retrieve the consumer window size for flow control, isBlockOnNonDurableSend() to know whether the producers created from the connection factory will block when sending non-durable messages, and so on).

Messages can be expired from a queue by using the expireMessages() method. If an expiry address is defined, messages will be sent to it, otherwise they are discarded. The queue's expiry address can be set with the setExpiryAddress() method.

Messages can also be sent to a dead letter address with the sendMessagesToDeadLetterAddress() method. It returns the number of messages which are sent to the dead letter address. If a dead letter address is not defined, message are removed from the queue and discarded. The queue's dead letter address can be set with the setDeadLetterAddress() method.

Messages can also be moved from a queue to another queue by using the moveMessages() method.

Messages can be listed from a queue by using the listMessages() method which returns an array of Map, one Map for each message.

Messages can also be removed from the queue by using the removeMessages() method which returns a boolean for the single message ID variant or the number of removed messages for the filter variant. The removeMessages() method takes a filter argument to remove only filtered messages. Setting the filter to an empty string will in effect remove all messages.

The number of messages in a queue is returned by the getMessageCount() method. Alternatively, the countMessages() will return the number of messages in the queue which match a given filter

The message priority can be changed by using the changeMessagesPriority() method which returns a boolean for the single message id variant or the number of updated messages for the filter variant.

Message counters can be listed for a queue with the listMessageCounter() and listMessageCounterHistory() methods (see Section 28.6, “Message Counters”)

The JMSQueueControl exposes JMS queue settings through its attributes (for example, isTemporary() to know whether the queue is temporary or not, isDurable() to know whether the queue is durable or not, and so on.)

The JMSQueueControl can pause and resume the underlying queue. When the queue is paused it will continue to receive messages but will not deliver them. When resumed again it will deliver the enqueued messages.

JMS topics subscriptions can be listed using the listAllSubscriptions(), listDurableSubscriptions(), listNonDurableSubscriptions() methods. These methods return arrays of Object representing the subscriptions information (subscription name, client ID, durability, message count, and so on). It is also possible to list the JMS messages for a given subscription with the listMessagesForSubscription() method.

Durable subscriptions can be dropped from the topic using the dropDurableSubscription() method.

The countMessagesForSubscription() method can be used to determine the number of messages held for a given subscription (with an optional message selector to determine the number of messages matching the selector).