The document describes how to use the choice component in Mule to conditionally route messages based on message properties. It provides an example XML configuration with two flows - flow1 sets a session property and flow2 uses a choice component to route the message based on checking the value of that session property, logging different messages depending on the result. When run, it demonstrates setting and accessing the session property across the two flows and the choice component routing the message to the appropriate logger based on the property value.

1. Choice component
10-12-2015

2. Introduction
• The choice flow control dynamically routes
messages based on message payload or
properties. It adds conditional programming
to a flow, similar to an if/then/else code block.

3. Example

4. • .mflow
• <?xml version="1.0" encoding="UTF-8"?>
• <mule xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking" xmlns:http="http://www.mulesoft.org/schema/mule/http"
xmlns:vm="http://www.mulesoft.org/schema/mule/vm" 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" version="EE-
3.4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="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/vm http://www.mulesoft.org/schema/mule/vm/current/mule-vm.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="MessagePropertiesFlow1" doc:name="MessagePropertiesFlow1">
• <http:inbound-endpoint exchange-pattern="request-response" host="localhost" port="8089" path="choice" doc:name="HTTP"/>
• <message-properties-transformer scope="session" doc:name="Message Properties">
• <add-message-property key="property1" value="mule"/>
• </message-properties-transformer>
• <logger message="--flow1--#[sessionVars['property1']]" level="INFO" doc:name="Logger"/>
• <vm:outbound-endpoint exchange-pattern="request-response" path="messageproperties" doc:name="VM"/>
• </flow>
• <flow name="MessagePropertiesFlow2" doc:name="MessagePropertiesFlow2">
• <vm:inbound-endpoint exchange-pattern="request-response" path="messageproperties" doc:name="VM"/>
• <logger message="---flow2--#[sessionVars['property1']]" level="INFO" doc:name="Logger"/>
• <choice doc:name="Choice">
• <when expression="#[sessionVars['property1']=='mule']">
• <logger message="--the value of session property (property1) is 'mule'" level="INFO" doc:name="Logger"/>
• </when>
• <otherwise>
• <logger message="--the value of session property (property1) is not 'mule'" level="INFO" doc:name="Logger"/>
• </otherwise>
• </choice>
• </flow>
• </mule>

5. • Output:
• INFO 2015-10-03 16:00:23,705 [[messageproperties].config.change.14.thread.1] org.mule.DefaultMuleContext:
• **********************************************************************
• * Application: messageproperties *
• * OS encoding: Cp1252, Mule encoding: UTF-8 *
• * *
• * Agents Running: *
• * Clustering Agent *
• * JMX Agent *
• **********************************************************************
• INFO 2015-10-03 16:00:23,706 [[messageproperties].config.change.14.thread.1]
org.mule.module.launcher.MuleDeploymentService:
• ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
• + Started app 'messageproperties' +
• ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
• INFO 2015-10-03 16:00:26,480 [[messageproperties].connector.http.mule.default.receiver.02]
org.mule.api.processor.LoggerMessageProcessor: --flow1--mule--studio
• INFO 2015-10-03 16:00:26,482 [[messageproperties].connector.http.mule.default.receiver.02]
org.mule.lifecycle.AbstractLifecycleManager: Initialising: 'connector.VM.mule.default.dispatcher.771015974'.
Object is: VMMessageDispatcher
• INFO 2015-10-03 16:00:26,482 [[messageproperties].connector.http.mule.default.receiver.02]
org.mule.lifecycle.AbstractLifecycleManager: Starting: 'connector.VM.mule.default.dispatcher.771015974'. Object
is: VMMessageDispatcher
• INFO 2015-10-03 16:00:26,489 [[messageproperties].connector.http.mule.default.receiver.02]
org.mule.api.processor.LoggerMessageProcessor: ---flow2--mule--studio

6. • Flow of execution:
1. URL to trigger the service from browser
http://localhost:8089/choice
2. session property is created using message
property component In flow1
3. Service displays session properties in flow1,
flow2
4. In flow2 the choice component checks the value
of the session property is ‘mule’ or not, if true then
it displays “the value of session property
(property1) is 'mule” else it goes and displays data
in default component