SI Aggregator - Timeout release strategy

[SARAL SAXENA]

Hi Amol,

As you have said....



PLEASE explain the concept of release strategy for a message group...as I am 100% clear on message reaper but not on message group..please if it is best you can tell with a example..!!

Hi ,
Is there is any way that I would configure only the release out startergy and I don't want to go for message reaper,,, I want that message group of 10 should be formed within 30 secnds and if somehow only 7 messages arrive in 30 seconds then those 7 messages group should be released ...can't release startergy alone handles this case itself..!!

[Gary Russell]

NO.

As we have said to you before, the aggregator is a passive component and only acts when messages arrive. To activate it outside of message arrival, you need some other component (the reaper).

[SARAL SAXENA]

NO.

As we have said to you before, the aggregator is a passive component and only acts when messages arrive. To activate it outside of message arrival, you need some other component (the reaper).

Hi Gary,

As we can set the release startergy in the xml configuration file itself...like the below...

bean id="timeout"
		class="org.springframework.integration.aggregator.TimeoutCountSequenceSizeReleaseStrategy">
		<constructor-arg name="threshold" value="1000" />
		<constructor-arg name="timeout" value="7000" />
	</bean>

Can we also define the corelation statergy bean also in xml file for grouping the messages according to same corelatioanal id...rite now in my application I am writing a separate pojo bean for corelational startergy and then passing it reference in aggregatoer in xml., I want thqt co relational startergy should also be there in xmll file itself just as the release startergy..!! is it possible could you please advise me and show some sample tags of that in the xml format..!!!

[Amol Nayak]

You can use a org.springframework.integration.aggregator.HeaderA ttributeCorrelationStrategy.
Define a bean like

        <bean id="correlationStrategy" class="org.springframework.integration.aggregator.HeaderAttributeCorrelationStrategy">
		<constructor-arg value="CORRELATING_ID"/>
	</bean>

Give the reference to this bean using the correlation-strategy attribute of the aggregator definition in the config

This will aggregate the messages based on the value of the header CORRELATING_ID in the message header

[SARAL SAXENA]

Hi Amol,

In my application I am using the corelation bean as follows....

import org.springframework.integration.Message;

public class CorrelationBean {
	//Not grouping based on correlation ids 
	public String correlationStrategy(Message<String> request){
		return "NO GROUPING";
	}
}

As seen above technically I doing no grouping on the basis of id's and I am passing the refence of this pojo in my configuration as ..

<bean id="correlationBean" class="com.walgreens.ods.producer.CorrelationBean" scope="prototype" />
<si:aggregator id="aggregator_2" input-channel="aggregator-input-channel_2" output-channel="aggregator-output-channel_2"
		
		ref="sampleAggregator" method="aggregateMessagaes"  		
		correlation-strategy="correlationBean" correlation-strategy-method="correlationStrategy" 
		release-strategy="releaseStrategyBean" release-strategy-method="releaseStrategy" 
		message-store="messageStore2"
		order="1" 
		send-partial-result-on-expiry="true"		
		send-timeout = "5000"
		>
	</si:aggregator>

I want to remove this pojo and I want all the configuration in xml file itself as I have done of release statergy , please guide me how this above bean would be look like in the xml file itself..!! thanks in advance..!!

[Amol Nayak]

I don't get what you mean, haven't you defined the correlation strategy bean in the xml file too?

[SARAL SAXENA]

I don't get what you mean, haven't you defined the correlation strategy bean in the xml file too?

I have already made a seprate java bean for correlation strategy and passes it reference in the xml configuration file itself, Now I want it completeley in xml configuration file itself ..no java bean I want to keep ..!!

[Pranav Kumar Varshney]

Hi Saral,

You can configure it via the correlation-strategy-expression attribute (correlation logic via a SpEL expression) instead of correlation-strategy attribute. Something like (example taken from reference manual)

correlation-strategy-expression="payload.person.id"

Similarly for ReleaseStrategy

release-strategy-expression="payload.size() gt 5"

Here you don't have to write beans, you can use SpEL to define your correlation and release strategy

Other thing that I observe is that with MessageGroupStoreReaper we can use MethodInvokingReleaseStrategy instead of TimeoutCountSequenceSizeReleaseStrategy. Write a bean and method that always return false. (I want all the messages to be released / expired at fixed interval)

        <bean id="myReleaseStrategy" class="com.test.MyReleaseStrategy" />
	
	<bean id="releaseStrategy"
		class="org.springframework.integration.aggregator.MethodInvokingReleaseStrategy">
		<constructor-arg name="object" ref="myReleaseStrategy" />
		<constructor-arg name="methodName" value="canRelease" />
	</bean>

public class MyReleaseStrategy {
	public boolean canRelease() {
		System.out.println("MyReleaseStrategy.canRelease called .....");
		return false;
	}
}

Regards,
Pranav

[SARAL SAXENA]

Hi Pranav ,
Thanks for the explnation it is working now,I done the corelational-startergy expression attribute via SPEL itself and it's working..!!Thanks a lot..!!