Poller and max-messages-per-poll

[spcmdr]

I need some more explanation on the use of poller.
I have understood that they are use to trigger event on channel for send retrieve.

What is the property max-messages-per-poll use for?
What is the default value for that property?

I have defined a default poller for my application.
How many message can be send consume at the same time.
Is there a way to define the number of thread that can be active is a channel ? (Maybe it’s the max-messages-per-poll property).

Regards

[oleg.zhurakousky]

Good question and is being a source of confusion for a few people, so we've recently updated documentation to provide more details on the Polling Consumer and its properties.
Here is the link: http://build.springsource.org/downlo...ollingconsumer
and this:http://build.springsource.org/downlo...#async-polling

Please respond here if it is still unclear and we'll follow up.

[spcmdr]

Hi

I have to admit that I don’t understand the need of a poller.
I may be naive but message are suppose to be send and receive by end point.


I tried this configuration:

<sioller default="true" max-messages-per-poll="10" task-executor="taskExecutor"/>
<task:executor id="taskExecutor" pool-size="10" queue-capacity="0"/>

And get the error:
Configuration problem: A <poller> must have a one and only one trigger configuration.

[eluis]

hi,

Since you have defined a default poller, it must have a trigger, try to use a cron or an interval-trigger.

Luis

[spcmdr]

Hi

What is the behavior of a poller.
When a message arrives to a channel,
-the message is consumed one at the time.
-a new thread is created to consume the message

Here is my configuration

<si:poller default="true" max-messages-per-poll="1000">
	<si:interval-trigger interval="100"/>
</si:poller>

<si:service-activator input-channel="inChannel" ref="myBean" method="execute" output-channel="outChannel" />

In fact my bean is thread safe.
I would like a thread to be created for each message for performance reason.

Regards

[Mark Fisher]

A poller is only needed if the source of Messages requires polling. In other words, when using an asynchronous MessageChannel with a "queue", its subscribers must poll. Likewise, when creating an inbound adapter for a directory on the File system, a poller is required.

Can you provide a bit more of your configuration so we can see where the poller is being used?

Thanks,
Mark

[spcmdr]

Here is the config

<bean id="connectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory" p:brokerURL="vm://localhost?broker.persistent=false"/>

<bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate" depends-on="connectionFactory">
	<property name="connectionFactory" ref="connectionFactory" />
	<property name="defaultDestinationName" value="orderQueue" />
	<property name="receiveTimeout" value="300" />
</bean>

<si:poller default="true" max-messages-per-poll="10">
	<si:interval-trigger interval="100"/>
</si:poller>

<sijms:channel id="jobChannel" queue-name="jobChannelQueue" error-handler="messagePublishingErrorHandler" />
<sijms:channel id="aggregateChannel" queue-name="aggregateChannelQueue" error-handler="messagePublishingErrorHandler" />
<sijms:channel id="deliverChannel" queue-name="deliverChannelQueue" error-handler="messagePublishingErrorHandler" />
<sijms:channel id="errorChannel" queue-name="errorQueue" error-handler="messagePublishingErrorHandler"/>
<si:channel id="jmsErrorChannel"><si:queue/></si:channel>

<sijms:message-driven-channel-adapter destination-name="orderQueue" channel="dispatcherChannel" connection-factory="connectionFactory"/>

<si:splitter input-channel="dispatcherChannel" ref="dispatcher" method="dispatch" output-channel="jobChannel"/>
<si:service-activator input-channel="jobChannel" ref="jobManager" method="executeTask" output-channel="aggregateChannel" />

<si:aggregator input-channel="aggregateChannel"  ref="aggregateManager" output-channel="deliverChannel"  send-timeout="7200000"/>

<si:outbound-channel-adapter channel="deliverChannel" ref="deliverManager" method="deliver" />
	
<!-- error message -->
<bean id="messagePublishingErrorHandler" class="org.springframework.integration.channel.MessagePublishingErrorHandler">
		<property name="defaultErrorChannel" ref="jmsErrorChannel" />
</bean>

<si:service-activator input-channel="jmsErrorChannel" ref="projectTaskExceptionHandler"/>

[orderQueue]-->dispatcherChannel-->jobChannel-->aggregateChannel-->deliverChannel
[all exception]-->(messagePublishingErrorHandler)-->jmsErrorChannel-->(projectTaskExceptionHandler)


Regards

[Mark Fisher]

I don't see anything in that configuration that would require a poller. Are you receiving an error when you remove the poller element?

[spcmdr]

Hi

I added a poller because spring wanted one.

Caused by: java.lang.IllegalArgumentException: No poller has been defined for endpoint 'org.springframework.integration.config.ConsumerEndpointFactoryBean#11', and no default poller is available within the context.
	at org.springframework.util.Assert.notNull(Assert.java:112)
	at org.springframework.integration.config.ConsumerEndpointFactoryBean.initializeEndpoint(ConsumerEndpointFactoryBean.java:152)
	at org.springframework.integration.config.ConsumerEndpointFactoryBean.afterPropertiesSet(ConsumerEndpointFactoryBean.java:107)

Regards

[Mark Fisher]

Sorry, I didn't notice the 'queue' sub-element within "jmsErrorChannel". Why did you decide to add a queue there?