Check if subflow has input

Question

I have Flow which is calling a subflow with a not required input variable. How can I check in the subflow if my subflow has got input?

So this could be my flow:

<?xml version="1.0" encoding="UTF-8"?>
<flow xmlns="http://www.springframework.org/schema/webflow"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
    http://www.springframework.org/schema/webflow 
    http://www.springframework.org/schema/webflow/spring-webflow-2.4.xsd ">

    <subflow-state id="withoutInput" subflow="ReportEinlesen"  >
     <transition on="ende" to="ReportUebersichtAnzeigen" />
</subflow-state>

  <decision-state id="somecondition">
     <if test="some condition" then="withnput" else="ende" />
  </decision-state>

  <subflow-state id="withInput" subflow="ReportEinlesen"  >
     <input name="Report" value="${Report.foo()}" />
     <transition on="ende" to="ReportUebersichtAnzeigen" />
  </subflow-state>

<end-state id="ende" />
</flow>

And this could be my subflow called ReportEinlesen:

<?xml version="1.0" encoding="UTF-8"?>
<flow xmlns="http://www.springframework.org/schema/webflow"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
    http://www.springframework.org/schema/webflow 
    http://www.springframework.org/schema/webflow/spring-webflow-2.4.xsd ">

  <decision-state id="anothercondition">
     <if test="has this subflow got input?" then="ShowYourInput" else="ende" />
  </decision-state>

<view-state id="ShowYourInput" >
   <transition on="Seen" to="ende" />
</view-state>

<end-state id="ende" />
</flow>

Answer 1

Create a delegate method and pass the input variable and then check if it is null or not