Support mule component <foreach />

[sanagaraj-pivotal]

What needs to be done

When component is detected, translate it to appropriate spring DSL translation

Example inputs and outputs

Sample 1

input

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:dw="http://www.mulesoft.org/schema/mule/ee/dw"
	xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
	xmlns:spring="http://www.springframework.org/schema/beans" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="
http://www.mulesoft.org/schema/mule/ee/dw http://www.mulesoft.org/schema/mule/ee/dw/current/dw.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
http://www.mulesoft.org/schema/mule/ee/tracking http://www.mulesoft.org/schema/mule/ee/tracking/current/mule-tracking-ee.xsd">
	<flow name="foreach">
		<http:listener config-ref="HTTP_Listener_Configuration" path="/foreach" doc:name="HTTP"/>	
        <foreach collection="#[['apple', 'banana', 'orange']]">
        	<logger message="#[payload]" level="INFO" />
        </foreach>
		<logger message="Done with for looping" level="INFO" />
	</flow>
</mule>

output:

    @Bean
    IntegrationFlow flow() {
        return IntegrationFlows.from(Http.inboundGateway("/foreachtest"))
                //TODO: translate expression #[['apple', 'banana', 'orange']] which must produces an array
                // to iterate over
                .split()
                .log()
                .aggregate()
                .log()
                .get();
    }

Sample 2

Children of foreach can be complex such as choice

<?xml version="1.0" encoding="UTF-8"?>

<mule xmlns:dw="http://www.mulesoft.org/schema/mule/ee/dw"
	xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
	xmlns:spring="http://www.springframework.org/schema/beans" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="
http://www.mulesoft.org/schema/mule/ee/dw http://www.mulesoft.org/schema/mule/ee/dw/current/dw.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
http://www.mulesoft.org/schema/mule/ee/tracking http://www.mulesoft.org/schema/mule/ee/tracking/current/mule-tracking-ee.xsd">
	<flow name="foreach">
		<http:listener config-ref="HTTP_Listener_Configuration" path="/foreach" doc:name="HTTP"/>	
        <foreach collection="#[[1, 2, 3, 4]]">
        	<logger message="#[payload]" level="INFO" />
        	<choice doc:name="Choice">
			<when expression="#[payload == 1]">
				<logger level="INFO" message="Ondu"></logger>
			</when>
			<when expression="#[payload == 2]">
				<logger level="INFO" message="Eradu"></logger>
			</when>
			<when expression="#[payload == 3]">
				<logger level="INFO" message="Mooru"></logger>
			</when>
			<otherwise>
				<logger level="INFO" message="Moorina mele"></logger>
			</otherwise>
		</choice>
        </foreach>
		<logger message="Done with for looping" level="INFO" />
	</flow>
</mule>

output

@Bean
    IntegrationFlow foreach() {
        return IntegrationFlows.from(Http.inboundChannelAdapter("/foreach")).handle((p, h) -> p)
                //TODO: translate expression #[[1, 2, 3, 4]] which must produces an array
                // to iterate over
                .split()
                /* TODO: LinkedMultiValueMap might not be apt, substitute with right input type*/
                .<LinkedMultiValueMap<String, String>, String>route(
                        p -> p.getFirst("dataKey") /*TODO: use apt condition*/,
                        m -> m
                                .subFlowMapping("dataValue" /*TODO: Translate dataValue to #[payload == 1]*/,
                                        sf -> sf.log(LoggingHandler.Level.INFO, "Ondu")
                                )
                                .subFlowMapping("dataValue" /*TODO: Translate dataValue to #[payload == 2]*/,
                                        sf -> sf.log(LoggingHandler.Level.INFO, "Eradu")
                                )
                                .subFlowMapping("dataValue" /*TODO: Translate dataValue to #[payload == 3]*/,
                                        sf -> sf.log(LoggingHandler.Level.INFO, "Mooru")
                                )
                                .resolutionRequired(false)
                                .defaultSubFlowMapping(sf -> sf.log(LoggingHandler.Level.INFO, "Moorina mele"))
                )
                .aggregate()
                .log(LoggingHandler.Level.INFO, "Done with for looping")
                .get();
    }

More information of foreach mule component can be found here

Additional notes

Batch sizing using foreach can be supported later