Class ActiveMQTopicSubscriber
- All Implemented Interfaces:
jakarta.jms.MessageConsumer
,jakarta.jms.TopicSubscriber
,AutoCloseable
,ActiveMQDispatcher
,StatsCapable
,MessageAvailableConsumer
TopicSubscriber
object to receive messages
that have been published to a topic. A TopicSubscriber
object
is the publish/subscribe form of a message consumer. A
MessageConsumer
can be created by using
Session.createConsumer
.
A TopicSession
allows the creation of multiple
TopicSubscriber
objects per topic. It will deliver each message for
a topic to each subscriber eligible to receive it. Each copy of the message
is treated as a completely separate message. Work done on one copy has no
effect on the others; acknowledging one does not acknowledge the others; one
message may be delivered immediately, while another waits for its subscriber
to process messages ahead of it.
Regular TopicSubscriber
objects are not durable. They receive
only messages that are published while they are active.
Messages filtered out by a subscriber's message selector will never be delivered to the subscriber. From the subscriber's perspective, they do not exist.
In some cases, a connection may both publish and subscribe to a topic. The
subscriber NoLocal
attribute allows a subscriber to inhibit
the delivery of messages published by its own connection.
If a client needs to receive all the messages published on a topic,
including the ones published while the subscriber is inactive, it uses a
durable TopicSubscriber
. The JMS provider retains a record
of this durable subscription and insures that all messages from the topic's
publishers are retained until they are acknowledged by this durable
subscriber or they have expired.
Sessions with durable subscribers must always provide the same client
identifier. In addition, each client must specify a name that uniquely
identifies (within client identifier) each durable subscription it creates.
Only one session at a time can have a TopicSubscriber
for a
particular durable subscription.
A client can change an existing durable subscription by creating a durable
TopicSubscriber
with the same name and a new topic and/or
message selector. Changing a durable subscription is equivalent to
unsubscribing (deleting) the old one and creating a new one.
The unsubscribe
method is used to delete a durable
subscription. The unsubscribe
method can be used at the
Session
or TopicSession
level. This method
deletes the state being maintained on behalf of the subscriber by its
provider.
Creating a MessageConsumer
provides the same features as
creating a TopicSubscriber
. To create a durable subscriber,
use of Session.CreateDurableSubscriber
is recommended. The
TopicSubscriber
is provided to support existing code.
- See Also:
-
Session.createConsumer(jakarta.jms.Destination)
Session.createDurableSubscriber(jakarta.jms.Topic, java.lang.String)
TopicSession
TopicSession.createSubscriber(jakarta.jms.Topic)
TopicSubscriber
MessageConsumer
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Field Summary
Fields inherited from class org.apache.activemq.ActiveMQMessageConsumer
deliveredMessages, info, session, unconsumedMessages
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Constructor Summary
ModifierConstructorDescriptionprotected
ActiveMQTopicSubscriber
(ActiveMQSession theSession, ConsumerId consumerId, ActiveMQDestination dest, String name, String selector, int prefetch, int maximumPendingMessageCount, boolean noLocalValue, boolean browserValue, boolean asyncDispatch) -
Method Summary
Modifier and TypeMethodDescriptionboolean
Gets theNoLocal
attribute for this subscriber.jakarta.jms.Topic
getTopic()
Gets theTopic
associated with this subscriber.Methods inherited from class org.apache.activemq.ActiveMQMessageConsumer
acknowledge, checkClosed, checkMessageListener, close, commit, dispatch, dispose, getAvailableListener, getConsumerId, getConsumerName, getConsumerStats, getDestination, getFailureError, getLastDeliveredSequenceId, getMessageListener, getMessageSelector, getMessageSize, getOptimizedAckScheduledAckInterval, getPrefetchNumber, getRedeliveryPolicy, getStats, getTransformer, hasMessageListener, isBrowser, isConsumerExpiryCheckEnabled, isDurableSubscriber, isInUse, isNoLocal, iterate, receive, receive, receiveNoWait, rollback, sendPullCommand, setAvailableListener, setConsumerExpiryCheckEnabled, setFailureError, setMessageListener, setOptimizeAcknowledge, setOptimizedAckScheduledAckInterval, setPrefetchSize, setRedeliveryPolicy, setTransformer, start, stop, toString
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface jakarta.jms.MessageConsumer
close, getMessageListener, getMessageSelector, receive, receive, receiveNoWait, setMessageListener
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Constructor Details
-
ActiveMQTopicSubscriber
protected ActiveMQTopicSubscriber(ActiveMQSession theSession, ConsumerId consumerId, ActiveMQDestination dest, String name, String selector, int prefetch, int maximumPendingMessageCount, boolean noLocalValue, boolean browserValue, boolean asyncDispatch) throws jakarta.jms.JMSException - Parameters:
theSession
-value
-dest
-name
-selector
-cnum
-noLocalValue
-browserValue
-asyncDispatch
-- Throws:
jakarta.jms.JMSException
-
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Method Details
-
getTopic
public jakarta.jms.Topic getTopic() throws jakarta.jms.JMSExceptionGets theTopic
associated with this subscriber.- Specified by:
getTopic
in interfacejakarta.jms.TopicSubscriber
- Returns:
- this subscriber's
Topic
- Throws:
jakarta.jms.JMSException
- if the JMS provider fails to get the topic for this topic subscriber due to some internal error.
-
getNoLocal
public boolean getNoLocal() throws jakarta.jms.JMSExceptionGets theNoLocal
attribute for this subscriber. The default value for this attribute is false.- Specified by:
getNoLocal
in interfacejakarta.jms.TopicSubscriber
- Returns:
- true if locally published messages are being inhibited
- Throws:
jakarta.jms.JMSException
- if the JMS provider fails to get theNoLocal
attribute for this topic subscriber due to some internal error.
-