Spring Webflow - Multiple evaluate statements in Action State
When executing mutiple expression statements in an action state you might encounter this exception
org.springframework.webflow.engine.NoMatchingTransitionException: No transition was matched on the event(s) signaled by the [X] action(s) that executed in this action state
This exception occurs because none of the evaluate statements trigger the transition. From the docs to trigger a transition a Action method has to return one of the following values
A java.lang.String value
A java.lang.Boolean value
A java.lang.Enum value
any other type success
So in our case our evaluate statements are not returning any of the event ids that will trigger a transition so we need to add the attribute element that will be set when the evaluate expression completes.
'The name of each action will become the qualifier for the actions result event' - webflow docs
Hope this helps someone, cause Spring webflows documents don't haha
org.springframework.webflow.engine.NoMatchingTransitionException: No transition was matched on the event(s) signaled by the [X] action(s) that executed in this action state
This exception occurs because none of the evaluate statements trigger the transition. From the docs to trigger a transition a Action method has to return one of the following values
A java.lang.String value
A java.lang.Boolean value
A java.lang.Enum value
any other type success
<action-state>
<evaluate expression="bean.setName('mark')"/>
<evaluate expression="bean.setAddress('Ireland')"/>
<transition to="myView"/>
</action-state>
So in our case our evaluate statements are not returning any of the event ids that will trigger a transition so we need to add the attribute element that will be set when the evaluate expression completes.
'The name of each action will become the qualifier for the actions result event' - webflow docs
<action-state>
<evaluate expression="bean.setName('mark')"/>
<evaluate expression="bean.setAddress('Ireland')">
<attribute name="name" value="complete"/>
</evaluate>
<transition on="complete.success" to="myView"/>
</action-state>
Hope this helps someone, cause Spring webflows documents don't haha
The article highlights an easy-to-miss behavior in Spring Web Flow when multiple expressions are used within the same action state. The NoMatchingTransitionException can occur even though the setter methods execute successfully, because their results do not produce event IDs that match the transition. The explanation of how action results are used as event qualifiers makes the underlying issue much clearer.
ReplyDeleteThis is particularly useful when working with Spring Boot Angular Full Stack Course applications, where understanding how framework actions communicate with the flow is important when diagnosing transition-related problems.
The distinction between an expression completing successfully and actually triggering a transition is also valuable for developers using Spring Boot Reactjs Full Stack Course technologies. It shows why checking the action result and event mapping is necessary rather than assuming that successful method execution automatically advances the flow.
ReplyDelete