Mule Session And Flow Var Example

This is simple example in mule demonstrating use of SessionVar , FlowVar , SubFlow , Vm , ForEach ,Groovy and Expression Component .

<http:listener-config port="8081" host="0.0.0.0"
  name="myRequestConfig" doc:name="HTTP Listener Configuration">
  <http:worker-threading-profile
   maxThreadsActive="15" />
 </http:listener-config>
<flow name="foreachexample">
<http:listener path="/foreach/test" config-ref="myRequestConfig"
   allowedMethods="GET" doc:name="HTTP"/>
     <logger message="RUNNNING poller ra " level="ERROR"/>
      <expression-component>
            java.util.ArrayList list = new java.util.ArrayList();
            list.add("abc");
            payload = list;
         </expression-component>
        <set-session-variable value="true" variableName="changeMe" doc:name="Session Variable" />
        <set-variable value="true" variableName="myFlowVar" doc:name="Flow Variable" />
        <foreach >
         <logger message="fdsf" level="ERROR"/>
         <flow-ref name="subFlowTest" />
         <flow-ref name="flow2" />
         <vm:outbound-endpoint path="/opt"/>
        </foreach>
        <vm:outbound-endpoint path="/opt"/>
        <logger message="changeme : #[sessionVars.changeMe]" level="ERROR"/>
    </flow>
    
 <sub-flow name="subFlowTest">
  <logger message="changeme flow var in sub flow : #[flowVars.myFlowVar]" level="ERROR"/>
  <logger message="changeme session var in sub flow: #[sessionVars.changeMe]" level="ERROR"/>
  <scripting:component doc:name="sleep">
   <scripting:script engine="groovy">
                <scripting:text><![CDATA[
            java.lang.Thread.sleep(5000);]]></scripting:text>
   </scripting:script>
  </scripting:component>
 </sub-flow>
 <flow name="flow2">
  <vm:inbound-endpoint path="/opt"></vm:inbound-endpoint>
  <logger message="changeme session var in flow 2: #[sessionVars.changeMe]" level="ERROR"/>
  <logger message="changeme flow var in flow 2: #[flowVars.myFlowVar]" level="ERROR"/>
 </flow>

FlowVars do not get lost when you call another flow by using flow-ref , but if you call another flow by vm or any other transport , then the flow variable will be lost and you will not be able to find it in the other flow . SessionVars will be present in each and every flow till the execution of the call . This example also demonstrates how can we write java code in our mule file using groovy component and expression component . Make sure to import the packages of the class which you intend to use , otherwise use fully qualified class name in your code .