ActiveMQ supports advisory messages which allows you to watch the system using regular JMS messages. Currently we have advisory messages that support

- -

consumers, producers and connections starting and stopping
temporary destinations being created and destroyed
messages expiring on topics and queues
brokers sending messages to destinations with no consumers.
connections starting and stopping

- - -

Advisory messages can be thought as some kind of administrative channel where you receive information regarding what is happening on your JMS provider along with what's happening with producers, consumers and destinations.

- -

When you look at a broker via JMX you will see the advisory topics prefixed with ActiveMQ.Advisory..

- -

Every Advisory has the message type 'Advisory' and some predefined message properties:

- -

property name	type	description	version
originBrokerId	StringProperty	the id of the broker where the advisory originated	5.x
originBrokerName	StringProperty	the name of the broker where the advisory originated	5.x
originBrokerURL	StringProperty	the first URL of the broker where the advisory originated	5.2

- - -

In addition, some messages carry a Command object - which carries more information for the advisory - e.g.

- -

A subscription to each of the destination returns an ActiveMQMessage. Specific DataStructure objects (ie. ConsumerInfo, ProducerInfo,ConnectionInfo) can be retrieve via getDataStructure method of ActiveMQMessage.

- -

For example:

-
-

- -

The following advisory topics are supported

- -

Client based advisories

The following advisory topics are supported

Client based advisories

Advisory Topics	Description	properties	Data Structure
ActiveMQ.Advisory.Connection	Connection start & stop messages
ActiveMQ.Advisory.Producer.Queue	Producer start & stop messages on a Queue	String='producerCount' - the number of producers	ProducerInfo
ActiveMQ.Advisory.Producer.Topic	Producer start & stop messages on a Topic	String='producerCount' - the number of producers	ProducerInfo
ActiveMQ.Advisory.Consumer.Queue	Consumer start & stop messages on a Queue	String='consumerCount' - the number of Consumers	ConsumerInfo
ActiveMQ.Advisory.Consumer.Topic	Consumer start & stop messages on a Topic	String='consumerCount' - the number of Consumers	ConsumerInfo

Note that the consumer start/stop advisory messages also have a consumerCount header to indicate the number of active consumers on the destination when the advisory message was sent. This means you can use the following selector to be notified when there are no active consumers on a given destination...

Destination and Message based advisories

Advisory Topics	Description	properties	Data Structure	default	PolicyEntry property
ActiveMQ.Advisory.Queue	Queue create & destroy	null	null	true	none
ActiveMQ.Advisory.Topic	Topic create & destroy	null	null	true	none
ActiveMQ.Advisory.TempQueue	Temporary Queue create & destroy	null	null	true	none
ActiveMQ.Advisory.TempTopic	Temporary Topic create & destroy	null	null	true	none
ActiveMQ.Advisory.Expired.Queue	Expired messages on a Queue	String='orignalMessageId' - the expired id	Message	true	none
ActiveMQ.Advisory.Expired.Topic	Expired messages on a Topic	String='orignalMessageId' - the expired id	Message	true	none
ActiveMQ.Advisory.NoConsumer.Queue	No consumer is available to process messages being sent on a Queue	null	Message	false	sendAdvisoryIfNoConsumers
ActiveMQ.Advisory.NoConsumer.Topic	No consumer is available to process messages being sent on a Topic	null	Message	false	sendAdvisoryIfNoConsumers

Destination and Message based advisories

Advisory Topics	Description	properties	Data Structure	default	PolicyEntry property
ActiveMQ.Advisory.Queue	Queue create & destroy	null	null	true	none
ActiveMQ.Advisory.Topic	Topic create & destroy	null	null	true	none
ActiveMQ.Advisory.TempQueue	Temporary Queue create & destroy	null	null	true	none
ActiveMQ.Advisory.TempTopic	Temporary Topic create & destroy	null	null	true	none
ActiveMQ.Advisory.Expired.Queue	Expired messages on a Queue	String='orignalMessageId' - the expired id	Message	true	none
ActiveMQ.Advisory.Expire d.Topic	Expired messages on a Topic	String='orignalMessageId' - the expired id	Message	true	none
ActiveMQ.Advisory.NoConsumer.Queue	No consumer is available to process messages being sent on a Queue	null	Message	false	sendAdvisoryIfNoConsumers
ActiveMQ.Adviso ry.NoConsumer.Topic	No consumer is available to process messages being sent on a Topic	null	Message	false	sendAdvisoryIfNoConsumers

New advisories in version 5.2

Advisory Topics	Description	properties	Data Structure	default	PolicyEntry property
ActiveMQ.Advisory.SlowConsumer.Queue	Slow Queue Consumer	String='consumerId' - the consumer id	ConsumerInfo	false	advisory ForSlowConsumers
ActiveMQ.Advisory.SlowConsumer.Topic	Slow Topic Consumer	String='consumerId' - the consumer id	ConsumerInfo	false	advisoryForSlowConsumers
ActiveMQ.Advisory.FastProducer.Queue	Fast Queue producer	String='producerId' - the producer id	ProducerInfo	false	advisdoryForFastProducers
ActiveMQ.Advisory. FastProducer.Topic	Fast Topic producer	String='consumerId' - the producer id	ProducerInfo	false	advisdoryForFastProducers
ActiveMQ.Advisory.MessageDiscarded.Queue	Message discarded	String='orignalMessageId' - the discarded id	Message	false	advisoryForDiscardingMessages
ActiveMQ.Advisory.MessageDiscarded.Topic	Message discarded	String='orignalMessageId' - the discarded id	Message	false	advisoryForDiscardingMessages
ActiveMQ.Advisory.MessageDelivered.Queue	Message delivered to the broker	String='orignalMessageId' - the delivered id	Message	false	advisoryForDelivery
ActiveMQ.Advisory.MessageDelivered.Topic	Message delivered to the broker	String='orignalMessageId' - the delivered id	Message	false	advisoryForDelivery
ActiveMQ.Advisory.MessageConsumed.Queue	Message consumed by a client	String='orignalMessageId' - the delivered id	Message	false	advisoryForConsumed
ActiveMQ.Advisory.MessageConsumed.Topic	Message consumed by a client	String='orignalMessageId' - the delivered id	Message	false	advisoryForConsumed
ActiveMQ.Advisory.FULL	A Usage resource is at its limit	String='usageName' - the name of Usag e resource	null	false	advisoryWhenFull
ActiveMQ.Advisory.MasterBroker	A broker is now the master in a master/slave configuration	null	null	true	none

New Advisories in 5.4

Advisory Topics	Description	properties	Data Structure	default	PolicyEntry property
ActiveMQ.Advisory.MessageDLQd.Queue	Message sent to DLQ	String='orignalMessageId' - the delivered id	Message	Always on	adv isoryForConsumed
ActiveMQ.Advisory.MessageDLQd.Topic	Message sent to DLQ	String='orignalMessageId' - the delivered id	Message	Always on	advisoryForConsumed

Network bridge advisories

Starting with ActiveMQ version 5.5 you can watch advisory topics for events related to the status of network bridges. You can get advisory messages when the network bridge is started or stopped.

Advisory Topics	Description	properties	Data Structure	default
ActiveMQ.Advisory.NetworkBridge	Network bridge being stopped or started	Boolean="started" - true if bridge is started, false if it is stopped -Boolean="createdByDuplex" - true if the bridge is created by remote network connector	BrokerInfo - provides data of the remote broker	Always on

Enabling advisories not turned on by default

The advisories that are not turned on by default (see the last column) can be enabled on a PolicyEntry in the ActiveMQ Broker Configuration - e.g. - to enable a message consumed advisory you can configure the following:

Disabling advisory messages

The use of advisory messages incurs a small overhead in terms of memory and connection resources that is related to the number of destinations in your system. In some cases it can make sense to disable all advisories.

and on your ActiveMQConnectionFactory (because a subscription to an advisory topic will auto create it) via the brokerUrl

or via java code using the 'watchTopicAdvisories' attribute on the ActiveMQConnectionFactory.

Using the destinations

All of the above destinations are really prefixes which are appended with important information (like the actual topic or queue, the client ID, producer ID, consumer ID etc). This allows you to reuse the power of publish/subscribe, Wildcards and Selectors to filter the advisory messages as you see fit.

For example if you want to subscribe to expired messages on a topic FOO.BAR you could subscribe to ActiveMQ.Advisory.Expired.Topic.FOO.BAR. To subscribe to all messages of a certain kind of advisory just append .> to the topic.

e.g. to subscribe to all the consumers starting and stopping to topics and queues subscribe to ActiveMQ.Advisory.Consumer..>.

Helper methods

Methods to get the advisory destination objects are available in AdvisorySupport through the following methods.

Some helper classes to deal with advisory messages are available in the advisories package.

Submitting patches

The easiest way to submit a patch is to create a new JIRA issue, attach the patch and tick the ASF license grant check box, tick the Patch Attached button on the issue then fire off an email to the Mailing Lists or Discussion Forums.

Becoming a commmitter

Once you've got involved as above, we may well invite you to be a committer. See Becoming a committer for more details.

Using the issue tracker

Before you can raise an issue in the issue tracker you need to register with it. This is quick & painless.

If you want to have a go at fixing an issue you need to be in the list of activemq-developers on the issue tracker. To join the group, please mail t he dev@activemq.codehaus.org mail list with the email address you used to register with the issue tracker and we'll add you to the group.

Why not dive in the issue tracker, and try tackle some of our outstanding issues?

Becoming a committer

The first step is contributing to the project; if you want to take that a step forward and become a fellow committer on the project then see the Committer Guide

Submitting patches

Becoming a commmitter

Once you've got involved as above, we may well invite you to be a committer. See Becoming a committer for more details.

Using the issue tracker

Before you can raise an issue in the issue tracker you need to register with it. This is quick & painless.

If you want to have a go at fixing an issue you need to be in the list of activemq-developers on the issue tracker. To join the group , please mail the dev@activemq.codehaus.org mail list with the email address you used to register with the issue tracker and we'll add you to the group.

Why not dive in the issue tracker, and try tackle some of our outstanding issues?

Becoming a committer

The first step is contributing to the project; if you want to take that a step forward and become a fellow committer on the project then see the Committer Guide

The following advisory topics are supported

Client based advisories

The following advisory topics are supported

Client based advisories

Destination and Message based advisories

Destination and Message based advisories

New advisories in version 5.2

New Advisories in 5.4

Network bridge advisories

Enabling advisories not turned on by default

Disabling advisory messages

Using the destinations

Helper methods

Getting in touch

If you find a bug or problem

Working on the code

Creating patches

Submitting patches

Becoming a commmitter

Using the issue tracker

Becoming a committer

Submitting patches

Becoming a commmitter

Using the issue tracker

Becoming a committer

How can I contribute to Apache ActiveMQ?

Getting in touch

If you find a bug or problem

Working on the code

Creating patches

Submitting patches

Becoming a commmitter

Using the issue tracker

Becoming a committer

Submitting patches

Becoming a commmitter

Using the issue tracker

Becoming a committer