Spring web flow, create subflow with input field - spring-webflow

Question

I am starting with spring web flow, reading and following the documentation. I have created a new flow:
test-flow.xml
<?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-2.0.xsd">
<var name="testName" class="com.project.TestView" />
<view-state id="test">
<on-entry>
<set name="flowScope.name" value="testName.name" />
</on-entry>
<transition on="test" to="saveName"/>
</view-state>
<subflow-state id="subTest" subflow="testSub-flow">
<input name="nameVar" value="name" />
<transition to="error" />
</subflow-state>
<view-state id="error" />
<end-state id="finish" />
</flow>
And I am trying to create a testSub-flow.xml
<?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-2.0.xsd">
<input type="String" name="nameVar" />
<on-start>
<evaluate expression="com.project.TestView.printSomething(nameVar)" result="flowScope.testPrint" />
</on-start>
<view-state id="printTest" >
<transition on="restart" to="endSub" />
</view-state>
<end-state id="endSub" />
</flow>
The method called is:
#Transactional(readOnly = true)
public String printSomething(String text){
System.out.print(text + " this is a test");
return text + " this is a test";
}
I get some exception in the browser when it is loading the main flow, test-flow.xml
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.webflow.execution.ActionExecutionException: Exception thrown executing [AnnotatedAction#6ca837 targetAction = [EvaluateAction#7aed3a expression = com.project.TestView.printSomething(nameVar), resultExpression = flowScope.testPrint], attributes = map[[empty]]] in state 'null' of flow 'test' -- action execution attributes were 'map[[empty]]'
What could be the problem?? Thanks in advance.

Answer 1

At first sight, it seems that it can not find any start-state. Try adding start-state attribute in flow tag:
<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-2.0.xsd"
start-state="test">
If that does not fix the problem, it could be that flow builder can not find a state named "saveName". The problem could be in this line:
<transition on="test" to="saveName"/>
If you want to invoke the subflow when "test" event occurs, you write "subTest" instead of "saveName" in order to call the subflow.
So, that line should be:
<transition on="test" to="subTest"/>
Also, note that you are not specifying any view for those view-states.
Hope this helps.