Condition expression returns non-Boolean

Flowable Engine
1

Hello everyone I’m getting this error:
“condition expression returns non-Boolean: isSomething==0 (java.lang.String)”

My bpmn is like this:

<process id="process" name="Process" isExecutable="true">
  <dataObject id="isSomething" name="Something" itemSubjectRef="xsd:int"/>
  <serviceTask id="serviceTask" name="Service Task" flowable:delegateExpression="${jd_myBean}"/>
  <sequenceFlow id="flow0" sourceRef="serviceTask" targetRef="gw4">
  <exclusiveGateway id="gw4"/>  
  <sequenceFlow id="flow1" sourceRef="gw4" targetRef="endGood">
      <conditionExpression xsi:type="tFormalExpression"><![CDATA[${isSomething==0}]]> 
   </conditionExpression>
    </sequenceFlow>
    <sequenceFlow id="flow2" sourceRef="gw4" targetRef="endBad">
      <conditionExpression xsi:type="tFormalExpression"><![CDATA[${isSomething==1}]]> 
     </conditionExpression>
      <endEventid id ="endGood" />
      <endEventid id ="endBad" />
   </sequenceFlow>
 </process>

On my bean I’m doing only this:

  if(exists){
            execution.setVariable("isSomething",0);
        }else{
            execution.setVariable("isSomething",1);
        }

I can’t understand why I’m getting this error . and when debugging I have this
image

Can anyone help me.

Thanks

2

Hi,

Are you sure that you pasted proper bpmn ?
I can’t see start element so you I expect FlowableException: No start element found for process … exception rather than yours.
Which version of the Flowable do you use?
Try to debug your process execution. Set breakpoint in UelExpressionCondition class.

3

bpmn is just an example.

I’m using Flowable 6.3.1

Try to debug your process execution. Set breakpoint in UelExpressionCondition class.

I will try that.

4

Ok :slight_smile:

So if it is only example I think that you have typo in you target process.
It looks like you forgot about ${} and it’s the reason that you’re getting:
condition expression returns non-Boolean: isSomething==0 (java.lang.String)
Check your sequence flow conditions.

1 Like
5

I verified and I have the ${} on my sequence flows like in example.

6

The problem was in a sub process that use the same variable and doesn’t has the ${}. Thank you rgorzkowski for your time.

7

Hi hugomar,

actually i also facing the same issue in some process and i am providing a typo ${} then also i am getting

org.flowable.common.engine.api.FlowableException: condition expression returns non-Boolean (sequenceFlowId: SequenceFlow_1tstpxv): false (java.lang.String) at org.flowable.engine.impl.el.UelExpressionCondition.evaluate(UelExpressionCondition.java:43) ~[flowable-engine-6.4.1.jar:6.4.1] at
this error
if some solution you found please share with me.

thanks in advance,

8

Hello @tiru.sadul

did you verify if in all of your condition you have ${xptoVar} or xptoVar is a boolean expession?

9

hi @hugomar

yes i verified and that xptoVar is boolean

But some process are not throwing this exception some are throwing the non-boolean exception

whichever process is throwing an exception i have cross checked is there any change i did but it is same only

so can you guide me to remove that exception

thanks
@tiru.sadul

10

Hi,
I have similar problem with condition ${loopVal} > 0 causes
Unhandled exception org.flowable.engine.common.api.FlowableException: condition expression returns non-Boolean: 2.0 > 0 (java.lang.String)
I have tried also Number() to get number but it causes condition expression returns non-Boolean: Number(2.0) > 0 (java.lang.String)
What can I do to avoid this problem?
Thanks in advance.

11

Found that right expression is
{loopVal > 0}** not **{loopVal}