org.springframework.jms.listener

Class DefaultMessageListenerContainer

java.lang.Object

org.springframework.jms.support.JmsAccessor

org.springframework.jms.support.destination.JmsDestinationAccessor

org.springframework.jms.listener.AbstractJmsListeningContainer

org.springframework.jms.listener.AbstractMessageListenerContainer

org.springframework.jms.listener.AbstractPollingMessageListenerContainer

org.springframework.jms.listener.DefaultMessageListenerContainer

All Implemented Interfaces:

org.springframework.beans.factory.Aware, org.springframework.beans.factory.BeanNameAware, org.springframework.beans.factory.DisposableBean, org.springframework.beans.factory.InitializingBean, org.springframework.context.Lifecycle, org.springframework.context.Phased, org.springframework.context.SmartLifecycle

Direct Known Subclasses:

DefaultMessageListenerContainer102

public class DefaultMessageListenerContainer
extends AbstractPollingMessageListenerContainer

Message listener container variant that uses plain JMS client APIs, specifically a loop of MessageConsumer.receive() calls that also allow for transactional reception of messages (registering them with XA transactions). Designed to work in a native JMS environment as well as in a J2EE environment, with only minimal differences in configuration.

This is a simple but nevertheless powerful form of message listener container. On startup, it obtains a fixed number of JMS Sessions to invoke the listener, and optionally allows for dynamic adaptation at runtime (up to a maximum number). Like SimpleMessageListenerContainer, its main advantage is its low level of runtime complexity, in particular the minimal requirements on the JMS provider: not even the JMS ServerSessionPool facility is required. Beyond that, it is fully self-recovering in case the broker is temporarily unavailable, and allows for stops/restarts as well as runtime changes to its configuration.

Actual MessageListener execution happens in asynchronous work units which are created through Spring's TaskExecutor abstraction. By default, the specified number of invoker tasks will be created on startup, according to the "concurrentConsumers" setting. Specify an alternative TaskExecutor to integrate with an existing thread pool facility (such as a J2EE server's), for example using a CommonJ WorkManager. With a native JMS setup, each of those listener threads is going to use a cached JMS Session and MessageConsumer (only refreshed in case of failure), using the JMS provider's resources as efficiently as possible.

Message reception and listener execution can automatically be wrapped in transactions by passing a Spring PlatformTransactionManager into the "transactionManager" property. This will usually be a org.springframework.transaction.jta.JtaTransactionManager in a J2EE environment, in combination with a JTA-aware JMS ConnectionFactory obtained from JNDI (check your J2EE server's documentation). Note that this listener container will automatically reobtain all JMS handles for each transaction in case an external transaction manager is specified, for compatibility with all J2EE servers (in particular JBoss). This non-caching behavior can be overridden through the "cacheLevel" / "cacheLevelName" property, enforcing caching of the Connection (or also Session and MessageConsumer) even if an external transaction manager is involved.

Dynamic scaling of the number of concurrent invokers can be activated by specifying a "maxConcurrentConsumers" value that is higher than the "concurrentConsumers" value. Since the latter's default is 1, you can also simply specify a "maxConcurrentConsumers" of e.g. 5, which will lead to dynamic scaling up to 5 concurrent consumers in case of increasing message load, as well as dynamic shrinking back to the standard number of consumers once the load decreases. Consider adapting the "idleTaskExecutionLimit" setting to control the lifespan of each new task, to avoid frequent scaling up and down, in particular if the ConnectionFactory does not pool JMS Sessions and/or the TaskExecutor does not pool threads (check your configuration!). Note that dynamic scaling only really makes sense for a queue in the first place; for a topic, you will typically stick with the default number of 1 consumer, otherwise you'd receive the same message multiple times on the same node.

Note: Don't use Spring's CachingConnectionFactory in combination with dynamic scaling. Ideally, don't use it with a message listener container at all, since it is generally preferable to let the listener container itself handle appropriate caching within its lifecycle. Also, stopping and restarting a listener container will only work with an independent, locally cached Connection - not with an externally cached one.

It is strongly recommended to either set "sessionTransacted" to "true" or specify an external "transactionManager". See the AbstractMessageListenerContainer javadoc for details on acknowledge modes and native transaction options, as well as the AbstractPollingMessageListenerContainer javadoc for details on configuring an external transaction manager. Note that for the default "AUTO_ACKNOWLEDGE" mode, this container applies automatic message acknowledgment before listener execution, with no redelivery in case of an exception.

Since:

2.0

Author:

Juergen Hoeller

See Also:

AbstractPollingMessageListenerContainer.setTransactionManager(org.springframework.transaction.PlatformTransactionManager), setCacheLevel(int), MessageConsumer.receive(long), SimpleMessageListenerContainer, JmsMessageEndpointManager

Nested Class Summary

Nested classes/interfaces inherited from class org.springframework.jms.listener.AbstractJmsListeningContainer

AbstractJmsListeningContainer.SharedConnectionNotInitializedException

Field Summary

Fields

Modifier and Type	Field and Description
static int	CACHE_AUTO Constant that indicates automatic choice of an appropriate caching level (depending on the transaction management strategy).
static int	CACHE_CONNECTION Constant that indicates to cache a shared JMS Connection for each listener thread.
static int	CACHE_CONSUMER Constant that indicates to cache a shared JMS Connection, a JMS Session, and a JMS MessageConsumer for each listener thread.
static int	CACHE_NONE Constant that indicates to cache no JMS resources at all.
static int	CACHE_SESSION Constant that indicates to cache a shared JMS Connection and a JMS Session for each listener thread.
static long	DEFAULT_RECOVERY_INTERVAL The default recovery interval: 5000 ms = 5 seconds.
static String	DEFAULT_THREAD_NAME_PREFIX Default thread name prefix: "DefaultMessageListenerContainer-".

Fields inherited from class org.springframework.jms.listener.AbstractPollingMessageListenerContainer

DEFAULT_RECEIVE_TIMEOUT

Fields inherited from class org.springframework.jms.listener.AbstractJmsListeningContainer

lifecycleMonitor, sharedConnectionMonitor

Fields inherited from class org.springframework.jms.support.JmsAccessor

logger

Constructor Summary

Constructors

Constructor and Description
DefaultMessageListenerContainer()

Method Summary

Methods

Modifier and Type	Method and Description
protected org.springframework.core.task.TaskExecutor	createDefaultTaskExecutor() Create a default TaskExecutor.
protected void	doInitialize() Creates the specified number of concurrent consumers, in the form of a JMS Session plus associated MessageConsumer running in a separate thread.
protected void	doRescheduleTask(Object task) Re-executes the given task via this listener container's TaskExecutor.
protected void	doShutdown() Destroy the registered JMS Sessions and associated MessageConsumers.
protected void	establishSharedConnection() Overridden to accept a failure in the initial setup - leaving it up to the asynchronous invokers to establish the shared Connection on first access.
int	getActiveConsumerCount() Return the number of currently active consumers.
int	getCacheLevel() Return the level of caching that this listener container is allowed to apply.
int	getConcurrentConsumers() Return the "concurrentConsumer" setting.
int	getIdleConsumerLimit() Return the limit for the number of idle consumers.
int	getIdleTaskExecutionLimit() Return the limit for idle executions of a consumer task.
int	getMaxConcurrentConsumers() Return the "maxConcurrentConsumer" setting.
int	getMaxMessagesPerTask() Return the maximum number of messages to process in one task.
int	getScheduledConsumerCount() Return the number of currently scheduled consumers.
protected void	handleListenerSetupFailure(Throwable ex, boolean alreadyRecovered) Handle the given exception that arose during setup of a listener.
void	initialize() Initialize this container.
boolean	isRecovering() Return whether this listener container is currently in a recovery attempt.
boolean	isRegisteredWithDestination() Return whether at least one consumer has entered a fixed registration with the target destination.
protected void	messageReceived(Object invoker, Session session) Tries scheduling a new invoker, since we know messages are coming in...
protected void	noMessageReceived(Object invoker, Session session) Marks the affected invoker as idle.
protected void	recoverAfterListenerSetupFailure() Recover this listener container after a listener failed to set itself up, for example re-establishing the underlying Connection.
protected void	refreshConnectionUntilSuccessful() Refresh the underlying Connection, not returning before an attempt has been successful.
protected void	refreshDestination() Refresh the JMS destination that this listener container operates on.
protected void	scheduleNewInvokerIfAppropriate() Schedule a new invoker, increasing the total number of scheduled invokers for this listener container, but only if the specified "maxConcurrentConsumers" limit has not been reached yet, and only if the specified "idleConsumerLimit" has not been reached either.
void	setCacheLevel(int cacheLevel) Specify the level of caching that this listener container is allowed to apply.
void	setCacheLevelName(String constantName) Specify the level of caching that this listener container is allowed to apply, in the form of the name of the corresponding constant: e.g.
void	setConcurrency(String concurrency) Specify concurrency limits via a "lower-upper" String, e.g.
void	setConcurrentConsumers(int concurrentConsumers) Specify the number of concurrent consumers to create.
void	setIdleConsumerLimit(int idleConsumerLimit) Specify the limit for the number of consumers that are allowed to be idle at any given time.
void	setIdleTaskExecutionLimit(int idleTaskExecutionLimit) Specify the limit for idle executions of a consumer task, not having received any message within its execution.
void	setMaxConcurrentConsumers(int maxConcurrentConsumers) Specify the maximum number of concurrent consumers to create.
void	setMaxMessagesPerTask(int maxMessagesPerTask) Specify the maximum number of messages to process in one task.
void	setRecoveryInterval(long recoveryInterval) Specify the interval between recovery attempts, in milliseconds.
void	setTaskExecutor(Executor taskExecutor) Set the Spring TaskExecutor to use for running the listener threads.
protected boolean	sharedConnectionEnabled() Use a shared JMS Connection depending on the "cacheLevel" setting.
protected void	sleepInbetweenRecoveryAttempts() Sleep according to the specified recovery interval.
void	start() Overridden to reset the stop callback, if any.
protected void	startSharedConnection() This implementations proceeds even after an exception thrown from Connection.start(), relying on listeners to perform appropriate recovery.
void	stop(Runnable callback) Stop this listener container, invoking the specific callback once all listener processing has actually stopped.
protected void	stopSharedConnection() This implementations proceeds even after an exception thrown from Connection.stop(), relying on listeners to perform appropriate recovery after a restart.

Methods inherited from class org.springframework.jms.listener.AbstractPollingMessageListenerContainer

createConsumer, createListenerConsumer, doReceiveAndExecute, getConnection, getSession, getTransactionManager, isPubSubNoLocal, isSessionLocallyTransacted, receiveAndExecute, receiveMessage, setPubSubNoLocal, setReceiveTimeout, setSessionTransacted, setTransactionManager, setTransactionName, setTransactionTimeout, shouldCommitAfterNoMessageReceived

Methods inherited from class org.springframework.jms.listener.AbstractMessageListenerContainer

checkMessageListener, commitIfNecessary, doExecuteListener, doInvokeListener, doInvokeListener, executeListener, getDefaultSubscriptionName, getDestination, getDestinationDescription, getDestinationName, getDurableSubscriptionName, getExceptionListener, getMessageListener, getMessageSelector, handleListenerException, invokeErrorHandler, invokeExceptionListener, invokeListener, isAcceptMessagesWhileStopping, isExposeListenerSession, isSubscriptionDurable, rollbackIfNecessary, rollbackOnExceptionIfNecessary, setAcceptMessagesWhileStopping, setDestination, setDestinationName, setDurableSubscriptionName, setErrorHandler, setExceptionListener, setExposeListenerSession, setMessageListener, setMessageSelector, setSubscriptionDurable, validateConfiguration

Methods inherited from class org.springframework.jms.listener.AbstractJmsListeningContainer

afterPropertiesSet, createSharedConnection, destroy, doStart, doStop, getBeanName, getClientId, getPausedTaskCount, getPhase, getSharedConnection, isActive, isAutoStartup, isRunning, logRejectedTask, prepareSharedConnection, refreshSharedConnection, rescheduleTaskIfNecessary, resumePausedTasks, runningAllowed, setAutoStartup, setBeanName, setClientId, setPhase, shutdown, stop

Methods inherited from class org.springframework.jms.support.destination.JmsDestinationAccessor

getDestinationResolver, isPubSubDomain, resolveDestinationName, setDestinationResolver, setPubSubDomain

Methods inherited from class org.springframework.jms.support.JmsAccessor

convertJmsAccessException, createConnection, createSession, getConnectionFactory, getSessionAcknowledgeMode, isClientAcknowledge, isSessionTransacted, setConnectionFactory, setSessionAcknowledgeMode, setSessionAcknowledgeModeName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_THREAD_NAME_PREFIX

public static final String DEFAULT_THREAD_NAME_PREFIX

Default thread name prefix: "DefaultMessageListenerContainer-".

DEFAULT_RECOVERY_INTERVAL

public static final long DEFAULT_RECOVERY_INTERVAL

The default recovery interval: 5000 ms = 5 seconds.

See Also:

Constant Field Values

CACHE_NONE

public static final int CACHE_NONE

Constant that indicates to cache no JMS resources at all.

See Also:

setCacheLevel(int), Constant Field Values

CACHE_CONNECTION

public static final int CACHE_CONNECTION

Constant that indicates to cache a shared JMS Connection for each listener thread.

See Also:

setCacheLevel(int), Constant Field Values

CACHE_SESSION

public static final int CACHE_SESSION

Constant that indicates to cache a shared JMS Connection and a JMS Session for each listener thread.

See Also:

setCacheLevel(int), Constant Field Values

CACHE_CONSUMER

public static final int CACHE_CONSUMER

Constant that indicates to cache a shared JMS Connection, a JMS Session, and a JMS MessageConsumer for each listener thread.

See Also:

setCacheLevel(int), Constant Field Values

CACHE_AUTO

public static final int CACHE_AUTO

Constant that indicates automatic choice of an appropriate caching level (depending on the transaction management strategy).

See Also:

setCacheLevel(int), Constant Field Values

Constructor Detail

DefaultMessageListenerContainer

public DefaultMessageListenerContainer()

Method Detail

setTaskExecutor

public void setTaskExecutor(Executor taskExecutor)

Set the Spring TaskExecutor to use for running the listener threads.

Default is a SimpleAsyncTaskExecutor, starting up a number of new threads, according to the specified number of concurrent consumers.

Specify an alternative TaskExecutor for integration with an existing thread pool. Note that this really only adds value if the threads are managed in a specific fashion, for example within a J2EE environment. A plain thread pool does not add much value, as this listener container will occupy a number of threads for its entire lifetime.

See Also:

setConcurrentConsumers(int), SimpleAsyncTaskExecutor, org.springframework.scheduling.commonj.WorkManagerTaskExecutor

setRecoveryInterval

public void setRecoveryInterval(long recoveryInterval)

Specify the interval between recovery attempts, in milliseconds. The default is 5000 ms, that is, 5 seconds.

See Also:

handleListenerSetupFailure(java.lang.Throwable, boolean)

setCacheLevelName

public void setCacheLevelName(String constantName)
                       throws IllegalArgumentException

Specify the level of caching that this listener container is allowed to apply, in the form of the name of the corresponding constant: e.g. "CACHE_CONNECTION".

Throws:

IllegalArgumentException

See Also:

setCacheLevel(int)

setCacheLevel

public void setCacheLevel(int cacheLevel)

Specify the level of caching that this listener container is allowed to apply.

Default is CACHE_NONE if an external transaction manager has been specified (to reobtain all resources freshly within the scope of the external transaction), and CACHE_CONSUMER otherwise (operating with local JMS resources).

Some J2EE servers only register their JMS resources with an ongoing XA transaction in case of a freshly obtained JMS Connection and Session, which is why this listener container by default does not cache any of those. However, if you want to optimize for a specific server, consider switching this setting to at least CACHE_CONNECTION or CACHE_SESSION even in conjunction with an external transaction manager.

See Also:

CACHE_NONE, CACHE_CONNECTION, CACHE_SESSION, CACHE_CONSUMER, setCacheLevelName(java.lang.String), AbstractPollingMessageListenerContainer.setTransactionManager(org.springframework.transaction.PlatformTransactionManager)

getCacheLevel

public int getCacheLevel()

Return the level of caching that this listener container is allowed to apply.

setConcurrency

public void setConcurrency(String concurrency)

Specify concurrency limits via a "lower-upper" String, e.g. "5-10", or a simple upper limit String, e.g. "10" (the lower limit will be 1 in this case).

This listener container will always hold on to the minimum number of consumers (setConcurrentConsumers(int)) and will slowly scale up to the maximum number of consumers setMaxConcurrentConsumers(int) in case of increasing load.

setConcurrentConsumers

public void setConcurrentConsumers(int concurrentConsumers)

Specify the number of concurrent consumers to create. Default is 1.

Specifying a higher value for this setting will increase the standard level of scheduled concurrent consumers at runtime: This is effectively the minimum number of concurrent consumers which will be scheduled at any given time. This is a static setting; for dynamic scaling, consider specifying the "maxConcurrentConsumers" setting instead.

Raising the number of concurrent consumers is recommendable in order to scale the consumption of messages coming in from a queue. However, note that any ordering guarantees are lost once multiple consumers are registered. In general, stick with 1 consumer for low-volume queues.

Do not raise the number of concurrent consumers for a topic, unless vendor-specific setup measures clearly allow for it. With regular setup, this would lead to concurrent consumption of the same message, which is hardly ever desirable.

This setting can be modified at runtime, for example through JMX.

See Also:

setMaxConcurrentConsumers(int)

getConcurrentConsumers

public final int getConcurrentConsumers()

Return the "concurrentConsumer" setting.

This returns the currently configured "concurrentConsumers" value; the number of currently scheduled/active consumers might differ.

See Also:

getScheduledConsumerCount(), getActiveConsumerCount()

setMaxConcurrentConsumers

public void setMaxConcurrentConsumers(int maxConcurrentConsumers)

Specify the maximum number of concurrent consumers to create. Default is 1.

If this setting is higher than "concurrentConsumers", the listener container will dynamically schedule new consumers at runtime, provided that enough incoming messages are encountered. Once the load goes down again, the number of consumers will be reduced to the standard level ("concurrentConsumers") again.

Raising the number of concurrent consumers is recommendable in order to scale the consumption of messages coming in from a queue. However, note that any ordering guarantees are lost once multiple consumers are registered. In general, stick with 1 consumer for low-volume queues.

Do not raise the number of concurrent consumers for a topic, unless vendor-specific setup measures clearly allow for it. With regular setup, this would lead to concurrent consumption of the same message, which is hardly ever desirable.

This setting can be modified at runtime, for example through JMX.

See Also:

setConcurrentConsumers(int)

getMaxConcurrentConsumers

public final int getMaxConcurrentConsumers()

Return the "maxConcurrentConsumer" setting.

This returns the currently configured "maxConcurrentConsumers" value; the number of currently scheduled/active consumers might differ.

See Also:

getScheduledConsumerCount(), getActiveConsumerCount()

setMaxMessagesPerTask

public void setMaxMessagesPerTask(int maxMessagesPerTask)

Specify the maximum number of messages to process in one task. More concretely, this limits the number of message reception attempts per task, which includes receive iterations that did not actually pick up a message until they hit their timeout (see the "receiveTimeout" property).

Default is unlimited (-1) in case of a standard TaskExecutor, reusing the original invoker threads until shutdown (at the expense of limited dynamic scheduling).

In case of a SchedulingTaskExecutor indicating a preference for short-lived tasks, the default is 10 instead. Specify a number of 10 to 100 messages to balance between rather long-lived and rather short-lived tasks here.

Long-lived tasks avoid frequent thread context switches through sticking with the same thread all the way through, while short-lived tasks allow thread pools to control the scheduling. Hence, thread pools will usually prefer short-lived tasks.

This setting can be modified at runtime, for example through JMX.

See Also:

setTaskExecutor(java.util.concurrent.Executor), AbstractPollingMessageListenerContainer.setReceiveTimeout(long), SchedulingTaskExecutor.prefersShortLivedTasks()

getMaxMessagesPerTask

public final int getMaxMessagesPerTask()

Return the maximum number of messages to process in one task.

setIdleConsumerLimit

public void setIdleConsumerLimit(int idleConsumerLimit)

Specify the limit for the number of consumers that are allowed to be idle at any given time.

This limit is used by the scheduleNewInvokerIfAppropriate() method to determine if a new invoker should be created. Increasing the limit causes invokers to be created more aggressively. This can be useful to ramp up the number of invokers faster.

The default is 1, only scheduling a new invoker (which is likely to be idle initially) if none of the existing invokers is currently idle.

getIdleConsumerLimit

public final int getIdleConsumerLimit()

Return the limit for the number of idle consumers.

setIdleTaskExecutionLimit

public void setIdleTaskExecutionLimit(int idleTaskExecutionLimit)

Specify the limit for idle executions of a consumer task, not having received any message within its execution. If this limit is reached, the task will shut down and leave receiving to other executing tasks.

The default is 1, closing idle resources early once a task didn't receive a message. This applies to dynamic scheduling only; see the "maxConcurrentConsumers" setting. The minimum number of consumers (see "concurrentConsumers") will be kept around until shutdown in any case.

Within each task execution, a number of message reception attempts (according to the "maxMessagesPerTask" setting) will each wait for an incoming message (according to the "receiveTimeout" setting). If all of those receive attempts in a given task return without a message, the task is considered idle with respect to received messages. Such a task may still be rescheduled; however, once it reached the specified "idleTaskExecutionLimit", it will shut down (in case of dynamic scaling).

Raise this limit if you encounter too frequent scaling up and down. With this limit being higher, an idle consumer will be kept around longer, avoiding the restart of a consumer once a new load of messages comes in. Alternatively, specify a higher "maxMessagesPerTask" and/or "receiveTimeout" value, which will also lead to idle consumers being kept around for a longer time (while also increasing the average execution time of each scheduled task).

This setting can be modified at runtime, for example through JMX.

See Also:

setMaxMessagesPerTask(int), AbstractPollingMessageListenerContainer.setReceiveTimeout(long)

getIdleTaskExecutionLimit

public final int getIdleTaskExecutionLimit()

Return the limit for idle executions of a consumer task.

initialize

public void initialize()

Description copied from class: AbstractJmsListeningContainer

Initialize this container.

Creates a JMS Connection, starts the Connection (if "autoStartup" hasn't been turned off), and calls AbstractJmsListeningContainer.doInitialize().

Overrides:

initialize in class AbstractPollingMessageListenerContainer

doInitialize

protected void doInitialize()
                     throws JMSException

Creates the specified number of concurrent consumers, in the form of a JMS Session plus associated MessageConsumer running in a separate thread.

Specified by:

doInitialize in class AbstractJmsListeningContainer

Throws:

JMSException - if registration failed

See Also:

scheduleNewInvoker(), setTaskExecutor(java.util.concurrent.Executor)

doShutdown

protected void doShutdown()
                   throws JMSException

Destroy the registered JMS Sessions and associated MessageConsumers.

Specified by:

doShutdown in class AbstractJmsListeningContainer

Throws:

JMSException - if shutdown failed

See Also:

AbstractJmsListeningContainer.shutdown()

start

public void start()
           throws JmsException

Overridden to reset the stop callback, if any.

Specified by:

start in interface org.springframework.context.Lifecycle

Overrides:

start in class AbstractJmsListeningContainer

Throws:

JmsException - if starting failed

See Also:

AbstractJmsListeningContainer.doStart()

stop

public void stop(Runnable callback)
          throws JmsException

Stop this listener container, invoking the specific callback once all listener processing has actually stopped.

Note: Further stop(runnable) calls (before processing has actually stopped) will override the specified callback. Only the latest specified callback will be invoked.

If a subsequent start() call restarts the listener container before it has fully stopped, the callback will not get invoked at all.

Specified by:

stop in interface org.springframework.context.SmartLifecycle

Overrides:

stop in class AbstractJmsListeningContainer

Parameters:

callback - the callback to invoke once listener processing has fully stopped

Throws:

JmsException - if stopping failed

See Also:

AbstractJmsListeningContainer.stop()

getScheduledConsumerCount

public final int getScheduledConsumerCount()

Return the number of currently scheduled consumers.

This number will always be between "concurrentConsumers" and "maxConcurrentConsumers", but might be higher than "activeConsumerCount" (in case some consumers are scheduled but not executing at the moment).

See Also:

getConcurrentConsumers(), getMaxConcurrentConsumers(), getActiveConsumerCount()

getActiveConsumerCount

public final int getActiveConsumerCount()

Return the number of currently active consumers.

This number will always be between "concurrentConsumers" and "maxConcurrentConsumers", but might be lower than "scheduledConsumerCount" (in case some consumers are scheduled but not executing at the moment).

See Also:

getConcurrentConsumers(), getMaxConcurrentConsumers(), getActiveConsumerCount()

isRegisteredWithDestination

public boolean isRegisteredWithDestination()

Return whether at least one consumer has entered a fixed registration with the target destination. This is particularly interesting for the pub-sub case where it might be important to have an actual consumer registered that is guaranteed not to miss any messages that are just about to be published.

This method may be polled after a start() call, until asynchronous registration of consumers has happened which is when the method will start returning true – provided that the listener container ever actually establishes a fixed registration. It will then keep returning true until shutdown, since the container will hold on to at least one consumer registration thereafter.

Note that a listener container is not bound to having a fixed registration in the first place. It may also keep recreating consumers for every invoker execution. This particularly depends on the cache level setting: only CACHE_CONSUMER will lead to a fixed registration.

createDefaultTaskExecutor

protected org.springframework.core.task.TaskExecutor createDefaultTaskExecutor()

Create a default TaskExecutor. Called if no explicit TaskExecutor has been specified.

The default implementation builds a SimpleAsyncTaskExecutor with the specified bean name (or the class name, if no bean name specified) as thread name prefix.

See Also:

SimpleAsyncTaskExecutor.SimpleAsyncTaskExecutor(String)

sharedConnectionEnabled

protected final boolean sharedConnectionEnabled()

Use a shared JMS Connection depending on the "cacheLevel" setting.

Specified by:

sharedConnectionEnabled in class AbstractJmsListeningContainer

See Also:

setCacheLevel(int), CACHE_CONNECTION

doRescheduleTask

protected void doRescheduleTask(Object task)

Re-executes the given task via this listener container's TaskExecutor.

Overrides:

doRescheduleTask in class AbstractJmsListeningContainer

Parameters:

task - the task object to reschedule

See Also:

setTaskExecutor(java.util.concurrent.Executor)

messageReceived

protected void messageReceived(Object invoker,
                   Session session)

Tries scheduling a new invoker, since we know messages are coming in...

Overrides:

messageReceived in class AbstractPollingMessageListenerContainer

Parameters:

invoker - the invoker object (passed through)

session - the receiving JMS Session

See Also:

scheduleNewInvokerIfAppropriate()

noMessageReceived

protected void noMessageReceived(Object invoker,
                     Session session)

Marks the affected invoker as idle.

Overrides:

noMessageReceived in class AbstractPollingMessageListenerContainer

Parameters:

invoker - the invoker object (passed through)

session - the receiving JMS Session

scheduleNewInvokerIfAppropriate

protected void scheduleNewInvokerIfAppropriate()

Schedule a new invoker, increasing the total number of scheduled invokers for this listener container, but only if the specified "maxConcurrentConsumers" limit has not been reached yet, and only if the specified "idleConsumerLimit" has not been reached either.

Called once a message has been received, in order to scale up while processing the message in the invoker that originally received it.

See Also:

setTaskExecutor(java.util.concurrent.Executor), getMaxConcurrentConsumers(), getIdleConsumerLimit()

establishSharedConnection

protected void establishSharedConnection()

Overridden to accept a failure in the initial setup - leaving it up to the asynchronous invokers to establish the shared Connection on first access.

Overrides:

establishSharedConnection in class AbstractJmsListeningContainer

See Also:

refreshConnectionUntilSuccessful()

startSharedConnection

protected void startSharedConnection()

This implementations proceeds even after an exception thrown from Connection.start(), relying on listeners to perform appropriate recovery.

Overrides:

startSharedConnection in class AbstractJmsListeningContainer

See Also:

Connection.start()

stopSharedConnection

protected void stopSharedConnection()

This implementations proceeds even after an exception thrown from Connection.stop(), relying on listeners to perform appropriate recovery after a restart.

Overrides:

stopSharedConnection in class AbstractJmsListeningContainer

See Also:

Connection.start()

handleListenerSetupFailure

protected void handleListenerSetupFailure(Throwable ex,
                              boolean alreadyRecovered)

Handle the given exception that arose during setup of a listener. Called for every such exception in every concurrent listener.

The default implementation logs the exception at warn level if not recovered yet, and at debug level if already recovered. Can be overridden in subclasses.

Parameters:

ex - the exception to handle

alreadyRecovered - whether a previously executing listener already recovered from the present listener setup failure (this usually indicates a follow-up failure than can be ignored other than for debug log purposes)

See Also:

recoverAfterListenerSetupFailure()

recoverAfterListenerSetupFailure

protected void recoverAfterListenerSetupFailure()

Recover this listener container after a listener failed to set itself up, for example re-establishing the underlying Connection.

The default implementation delegates to DefaultMessageListenerContainer's recovery-capable refreshConnectionUntilSuccessful() method, which will try to re-establish a Connection to the JMS provider both for the shared and the non-shared Connection case.

See Also:

refreshConnectionUntilSuccessful(), refreshDestination()

refreshConnectionUntilSuccessful

protected void refreshConnectionUntilSuccessful()

Refresh the underlying Connection, not returning before an attempt has been successful. Called in case of a shared Connection as well as without shared Connection, so either needs to operate on the shared Connection or on a temporary Connection that just gets established for validation purposes.

The default implementation retries until it successfully established a Connection, for as long as this message listener container is running. Applies the specified recovery interval between retries.

See Also:

setRecoveryInterval(long), start(), AbstractJmsListeningContainer.stop()

refreshDestination

protected void refreshDestination()

Refresh the JMS destination that this listener container operates on.

Called after listener setup failure, assuming that a cached Destination object might have become invalid (a typical case on WebLogic JMS).

The default implementation removes the destination from a DestinationResolver's cache, in case of a CachingDestinationResolver.

See Also:

AbstractMessageListenerContainer.setDestinationName(java.lang.String), CachingDestinationResolver

sleepInbetweenRecoveryAttempts

protected void sleepInbetweenRecoveryAttempts()

Sleep according to the specified recovery interval. Called between recovery attempts.

isRecovering

public final boolean isRecovering()

Return whether this listener container is currently in a recovery attempt.

May be used to detect recovery phases but also the end of a recovery phase, with isRecovering() switching to false after having been found to return true before.

See Also:

recoverAfterListenerSetupFailure()