Best loan quotation problem solution using spring integration scatter-gather EIP pattern.

best-quote.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:int="http://www.springframework.org/schema/integration"
	xmlns:int-scripting="http://www.springframework.org/schema/integration/scripting"
	xmlns:stream="http://www.springframework.org/schema/integration/stream"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:task="http://www.springframework.org/schema/task"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
		http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context
		http://www.springframework.org/schema/context/spring-context.xsd
		http://www.springframework.org/schema/integration
		http://www.springframework.org/schema/integration/spring-integration.xsd
		http://www.springframework.org/schema/integration/stream
      	http://www.springframework.org/schema/integration/stream/spring-integration-stream.xsd
      	http://www.springframework.org/schema/integration/scripting
      	http://www.springframework.org/schema/integration/scripting/spring-integration-scripting.xsd
      	http://www.springframework.org/schema/task
      	http://www.springframework.org/schema/task/spring-task.xsd">
	
	
	<int:gateway service-interface="com.spintegration.test.scatter.gather.service.BestQuotationSearchService" default-request-channel="ch1" default-reply-timeout="1000"/>
	
	<int:channel id="ch1"/>
	
	<int:scatter-gather input-channel="ch1" scatter-channel="scatter_channel" gather-channel="ch2" output-channel="quotations_result_channel" gather-timeout="3000" requires-reply="false">
		<int:gatherer release-strategy-expression="size()==2"/>	
	</int:scatter-gather>	
		
	<int:channel id="quotations_result_channel"/>

	<int:transformer input-channel="quotations_result_channel">
		<int-scripting:script lang="javascript">
		<![CDATA[
		     (function(){
		     	 var indexRate = 10000; 
		     	 for(i=0; i<payload.size(); i++){
		     	   if(indexRate > payload.get(i))
		     	 	  indexRate = payload.get(i);
		     	 }
		     	 return indexRate;
		     })();
   		]]>			
		</int-scripting:script>
	</int:transformer>
	
	<int:publish-subscribe-channel id="scatter_channel" apply-sequence="true" task-executor="taskExecutor"/>
	
	<int:channel id="ch2"/>		
	
	<!-- Exemplary quotation services  -->
	<int:transformer input-channel="scatter_channel" expression="payload * 0.03" output-channel="ch2"/>
	<int:transformer input-channel="scatter_channel" expression="payload * 0.02" output-channel="ch2"/>
	
	<task:executor id="taskExecutor" queue-capacity="2" pool-size="2-2"/>

</beans>

BestQuotationSearchService.java

public interface BestQuotationSearchService {
	
	public Double findBestQuotation(Double loanAmount);

	
}

log.sv

17:09:44.822 DEBUG [main][org.springframework.integration.handler.ScatterGatherHandler] org.springframework.integration.handler.ScatterGatherHandler#0 received message: GenericMessage [payload=100.0, headers={timestamp=1425733784821, id=3b1f485d-3718-c330-e55c-14887068ee09, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74}]
17:09:44.826 DEBUG [main][org.springframework.integration.channel.DefaultHeaderChannelRegistry] Registered org.springframework.integration.channel.QueueChannel@56849d45 as 5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1
17:09:44.828 DEBUG [taskExecutor-1][org.springframework.integration.transformer.MessageTransformingHandler] org.springframework.integration.transformer.MessageTransformingHandler@43b69758 received message: GenericMessage [payload=100.0, headers={timestamp=1425733784827, id=c5c01189-cc0b-ac17-8bc1-06f5c7d4dffd, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, replyChannel=ch2, sequenceSize=2, sequenceNumber=1}]
17:09:44.828 DEBUG [main][org.springframework.integration.channel.PublishSubscribeChannel] postSend (sent=true) on channel 'scatter_channel', message: GenericMessage [payload=100.0, headers={timestamp=1425733784826, id=20e8f205-c3c1-db17-fc14-3acb7f7314e1, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, replyChannel=ch2}]
17:09:44.828 DEBUG [taskExecutor-1][org.springframework.beans.factory.support.DefaultListableBeanFactory] Returning cached instance of singleton bean 'integrationEvaluationContext'
17:09:44.828 DEBUG [taskExecutor-2][org.springframework.integration.transformer.MessageTransformingHandler] org.springframework.integration.transformer.MessageTransformingHandler@29a69136 received message: GenericMessage [payload=100.0, headers={timestamp=1425733784827, id=87496b13-ec4d-00a6-884b-2d3a69f9edf6, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, replyChannel=ch2, sequenceSize=2, sequenceNumber=2}]
17:09:44.828 DEBUG [taskExecutor-2][org.springframework.beans.factory.support.DefaultListableBeanFactory] Returning cached instance of singleton bean 'integrationEvaluationContext'
17:09:44.829 DEBUG [taskExecutor-1][org.springframework.integration.aggregator.AggregatingMessageHandler] org.springframework.integration.handler.ScatterGatherHandler#0.gatherer received message: GenericMessage [payload=3.0, headers={timestamp=1425733784829, id=5201ab00-d1de-477f-c2dd-97635f21db04, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, replyChannel=ch2, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, sequenceSize=2, sequenceNumber=1}]
17:09:44.829 DEBUG [taskExecutor-2][org.springframework.integration.aggregator.AggregatingMessageHandler] org.springframework.integration.handler.ScatterGatherHandler#0.gatherer received message: GenericMessage [payload=2.0, headers={timestamp=1425733784829, id=0223fe83-8619-5340-a0ac-de9a6e02f587, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, replyChannel=ch2, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, sequenceSize=2, sequenceNumber=2}]
17:09:44.829 DEBUG [taskExecutor-1][org.springframework.integration.aggregator.AbstractCorrelatingMessageHandler] Handling message with correlationKey [20e8f205-c3c1-db17-fc14-3acb7f7314e1]: GenericMessage [payload=3.0, headers={timestamp=1425733784829, id=5201ab00-d1de-477f-c2dd-97635f21db04, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, replyChannel=ch2, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, sequenceSize=2, sequenceNumber=1}]
17:09:44.829 DEBUG [taskExecutor-2][org.springframework.integration.aggregator.AbstractCorrelatingMessageHandler] Handling message with correlationKey [20e8f205-c3c1-db17-fc14-3acb7f7314e1]: GenericMessage [payload=2.0, headers={timestamp=1425733784829, id=0223fe83-8619-5340-a0ac-de9a6e02f587, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, replyChannel=ch2, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, sequenceSize=2, sequenceNumber=2}]
17:09:44.831 DEBUG [taskExecutor-1][org.springframework.integration.channel.DirectChannel] postSend (sent=true) on channel 'ch2', message: GenericMessage [payload=3.0, headers={timestamp=1425733784829, id=5201ab00-d1de-477f-c2dd-97635f21db04, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, replyChannel=ch2, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, sequenceSize=2, sequenceNumber=1}]
17:09:44.831 DEBUG [taskExecutor-2][org.springframework.integration.aggregator.AbstractCorrelatingMessageHandler] Completing group with correlationKey [20e8f205-c3c1-db17-fc14-3acb7f7314e1]
17:09:44.832 DEBUG [taskExecutor-2][org.springframework.integration.channel.DefaultHeaderChannelRegistry] Retrieved org.springframework.integration.channel.QueueChannel@56849d45 with 5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1
17:09:44.832 DEBUG [taskExecutor-2][org.springframework.integration.channel.QueueChannel] postSend (sent=true) on channel 'org.springframework.integration.channel.QueueChannel@56849d45', message: GenericMessage [payload=[3.0, 2.0], headers={timestamp=1425733784831, id=45680b20-ae71-1454-3359-23c3be318efa, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, replyChannel=ch2, sequenceSize=2, sequenceNumber=2}]
17:09:44.832 DEBUG [main][org.springframework.integration.channel.QueueChannel] postReceive on channel 'org.springframework.integration.channel.QueueChannel@56849d45', message: GenericMessage [payload=[3.0, 2.0], headers={timestamp=1425733784831, id=45680b20-ae71-1454-3359-23c3be318efa, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, replyChannel=ch2, sequenceSize=2, sequenceNumber=2}]
17:09:44.832 DEBUG [taskExecutor-2][org.springframework.integration.channel.DirectChannel] postSend (sent=true) on channel 'ch2', message: GenericMessage [payload=2.0, headers={timestamp=1425733784829, id=0223fe83-8619-5340-a0ac-de9a6e02f587, gatherResultChannel=5c6f9dd4-8774-4ca3-824f-3419fcd13ec8:1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@12420d74, replyChannel=ch2, correlationId=20e8f205-c3c1-db17-fc14-3acb7f7314e1, sequenceSize=2, sequenceNumber=2}]