topic Re: Skip expression on User Task in Alfresco Archive

Skip expression on User Task

hari — Thu, 28 Apr 2016 11:53:48 GMT

Hi, I see a property called "Skip expression" on a user task in eclipse. I could not see any information being available about it anywhere so I am requesting you here to please tell us more about it. Thanks, Hari.

Re: Skip expression on User Task

martin_grofcik — Mon, 02 May 2016 06:22:47 GMT

Hi Hari,

Have a look on org.activiti.examples.bpmn.usertask.SkipExpressionUserTaskTest
Regards
Martin

Re: Skip expression on User Task

hari — Mon, 02 May 2016 06:47:02 GMT

Thanks Martin,

Looking at that, I could see that if the expression evaluates to true, the user task is skipped and the execution moves to the next step.
So from which version of Activiti is this available in community version ?
Is it also available in Activiti Enterprise ? If so, from which version ?

Re: Skip expression on User Task

jbarrez — Tue, 03 May 2016 12:44:59 GMT

"So from which version of Activiti is this available in community version ? "

5.17

"Is it also available in Activiti Enterprise ? If so, from which version ?"

Yes … but not via the editor (yet)

Re: Skip expression on User Task

hari — Wed, 04 May 2016 07:36:59 GMT

My BPMN goes below.

<code>
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:activiti="http://activiti.org/bpmn" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlnsmgdc="http://www.omg.org/spec/DD/20100524/DC" xmlnsmgdi="http://www.omg.org/spec/DD/20100524/DI" typeLanguage="http://www.w3.org/2001/XMLSchema" expressionLanguage="http://www.w3.org/1999/XPath" targetNamespace="http://activiti.org/bpmn20" id="definitions">
<process id="test1_called" name="called process" isExecutable="true">
    <startEvent id="start" name="start process">
      <extensionElements>
        <activiti:formProperty id="fname" name="FName" type="string"></activiti:formProperty>
      </extensionElements>
    </startEvent>
    <userTask id="CNV_human1" name="CNV_human1" activiti:assignee="Hari" activiti:skipExpression="${execution.getVariable('fname')=="Hari"}">
      <extensionElements>
        <activiti:formProperty id="name" name="Name" type="string"></activiti:formProperty>
        <activiti:formProperty id="myenum" name="Enum" type="enum">
          <activiti:value id="Hi" name="Hello"></activiti:value>
          <activiti:value id="Bye" name="Tata"></activiti:value>
        </activiti:formProperty>
      </extensionElements>
    </userTask>
    <userTask id="CNV_human11" name="CNV_human11" activiti:assignee="Hari"></userTask>
    <endEvent id="end"></endEvent>
    <sequenceFlow id="flow2" sourceRef="CNV_human1" targetRef="CNV_human11"></sequenceFlow>
    <sequenceFlow id="flow3" sourceRef="CNV_human11" targetRef="end"></sequenceFlow>
    <userTask id="usertask1" name="Not Hari" activiti:assignee="Hari"></userTask>
    <sequenceFlow id="flow5" sourceRef="usertask1" targetRef="end"></sequenceFlow>
    <exclusiveGateway id="exclusivegateway1" name="Exclusive Gateway" default="flow8"></exclusiveGateway>
    <sequenceFlow id="flow6" sourceRef="start" targetRef="exclusivegateway1"></sequenceFlow>
    <sequenceFlow id="flow7" sourceRef="exclusivegateway1" targetRef="CNV_human1">
      <conditionExpression xsi:type="tFormalExpression"><![CDATA[${fname=="Hari"}]]></conditionExpression>
    </sequenceFlow>
    <sequenceFlow id="flow8" sourceRef="exclusivegateway1" targetRef="usertask1"></sequenceFlow>
</process>
<bpmndi:BPMNDiagram id="BPMNDiagram_test1_called">
    <bpmndi:BPMNPlane bpmnElement="test1_called" id="BPMNPlane_test1_called">
      <bpmndi:BPMNShape bpmnElement="start" id="BPMNShape_start">
        <omgdc:Bounds height="35.0" width="35.0" x="60.0" y="173.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="CNV_human1" id="BPMNShape_CNV_human1">
        <omgdc:Bounds height="60.0" width="100.0" x="310.0" y="59.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="CNV_human11" id="BPMNShape_CNV_human11">
        <omgdc:Bounds height="60.0" width="100.0" x="470.0" y="59.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="end" id="BPMNShape_end">
        <omgdc:Bounds height="35.0" width="35.0" x="790.0" y="153.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="usertask1" id="BPMNShape_usertask1">
        <omgdc:Bounds height="55.0" width="105.0" x="411.0" y="202.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="exclusivegateway1" id="BPMNShape_exclusivegateway1">
        <omgdc:Bounds height="40.0" width="40.0" x="190.0" y="170.0"></omgdc:Bounds>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge bpmnElement="flow2" id="BPMNEdge_flow2">
        <omgdi:waypoint x="410.0" y="89.0"></omgdi:waypoint>
        <omgdi:waypoint x="470.0" y="89.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow3" id="BPMNEdge_flow3">
        <omgdi:waypoint x="520.0" y="119.0"></omgdi:waypoint>
        <omgdi:waypoint x="807.0" y="153.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow5" id="BPMNEdge_flow5">
        <omgdi:waypoint x="463.0" y="202.0"></omgdi:waypoint>
        <omgdi:waypoint x="807.0" y="188.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow6" id="BPMNEdge_flow6">
        <omgdi:waypoint x="95.0" y="190.0"></omgdi:waypoint>
        <omgdi:waypoint x="190.0" y="190.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow7" id="BPMNEdge_flow7">
        <omgdi:waypoint x="210.0" y="170.0"></omgdi:waypoint>
        <omgdi:waypoint x="210.0" y="89.0"></omgdi:waypoint>
        <omgdi:waypoint x="310.0" y="89.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="flow8" id="BPMNEdge_flow8">
        <omgdi:waypoint x="210.0" y="210.0"></omgdi:waypoint>
        <omgdi:waypoint x="210.0" y="229.0"></omgdi:waypoint>
        <omgdi:waypoint x="411.0" y="229.0"></omgdi:waypoint>
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
</bpmndi:BPMNDiagram>
</definitions>
</code>

Re: Skip expression on User Task

hari — Thu, 05 May 2016 05:21:33 GMT

Question # 2
I've seen skip expression on sequence flow also. When I had both condition and skip expression, it just followed the condition and skipped the skip expression. Can someone please tell me whats the difference between condition and skip expression on a sequence flow ?

Question # 3
I was able to use the below code to get the task skipped partially but not how I wanted it to be. With the below scenario, I could see 2 user tasks getting created 1st one is CNV_human1 and CNV_human11. So I could understand that since the skip expression was on CNV_human1 and since it evaluated to true, the execution went ahead to CNV_human11. But my problem is I still see CNV_human1 in my inbox.
<code>
Map<String,Object> variables = new HashMap<String, Object>();
variables.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
variables.put("fname", "Hari");

tas.startBPM("Hari", "test1_called", variables, "MyTenant");
</code>

Question#4
Now as you read in Question#3, I have 2 user tasks in my inbox but when I try to complete any of them, I see this error "UserTask should not be signalled before complete". What is it that I have done incorrectly here ?

Re: Skip expression on User Task

jbarrez — Tue, 10 May 2016 10:00:20 GMT

Q3) The skip expression on a sequence flow will _take_ it, regardless of the condition:
<code>
Expression skipExpression = outgoingTransition.getSkipExpression();

      if (!SkipExpressionUtil.isSkipExpressionEnabled(execution, skipExpression)) {
        if (defaultSequenceFlow == null || !outgoingTransition.getId().equals(defaultSequenceFlow)) {
          Condition condition = (Condition) outgoingTransition.getProperty(BpmnParse.PROPERTYNAME_CONDITION);
          if (condition == null || !checkConditions || condition.evaluate(outgoingTransition.getId(), execution)) {
            transitionsToTake.add(outgoingTransition);
          }
        }

      } else if (SkipExpressionUtil.shouldSkipFlowElement(execution, skipExpression)){
        transitionsToTake.add(outgoingTransition);
      }
    }
</code>

Q3) That should not happen. If the skip expression is true, the task is completed immediately after creation:

<code>
task.fireEvent(TaskListener.EVENTNAME_CREATE);

    if (SkipExpressionUtil.isSkipExpressionEnabled(execution, activeSkipExpression) &&
        SkipExpressionUtil.shouldSkipFlowElement(execution, activeSkipExpression)) {

      task.complete(null, false);
    }
</code>

Q4) That sounds odd … do you have a simple unit test with this process demonstrating this?

Re: Skip expression on User Task

hari — Thu, 19 May 2016 11:01:45 GMT

Thanks Barrez,

Please find the Unit Test Case attached here as txt. Please rename it to zip and unzip the content.
One difference (Not sure what caused the difference) which I noticed now is that, even after I have mentioned Skip Expression on Human Task1, earlier I had 2 tasks in my inbox one at Human Task1 and the other at Human Task2 and I wasn't able to complete any of them. Now here I just see one Human Task at Human Task1 which has skip expression but still it got struck there.
Am I doing something wrong here ?

Re: Skip expression on User Task

jbarrez — Thu, 19 May 2016 11:31:24 GMT

You need to add the special variable to enable it:

<code>
mpvar.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
</code>

Re: Skip expression on User Task

hari — Thu, 19 May 2016 11:38:10 GMT

Thanks Barrez. I just tried it with your suggestion.
Now I see both the Human Tasks assigned to me. Which should not be the case. The first task should have been completed. Below is the output that I see.

STARTED PROCESS
=====================================================================================
Human Task 1
Human Task 2
END
=====================================================================================

Re: Skip expression on User Task

hari — Mon, 30 May 2016 05:46:51 GMT

To add to the above issue, the complete doesn't seem to work.
Below is the modified code as per your suggestion. Also the other change is that I have added code to try to complete the task.

Did I miss something again ?
<code>
public void test() {
HashMap<String,Object> mpvar = new HashMap<String,Object>();
mpvar.put("fname", "Hari");
mpvar.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
ProcessInstance processInstance = activitiRule.getRuntimeService().startProcessInstanceByKey("TestSkipExp",mpvar);
System.out.println("STARTED PROCESS");
System.out.println("=======================================================================");

List<Task> tasks = activitiRule.getTaskService().createTaskQuery().taskAssignee("Hari").list();
for(Task t:tasks){
   System.out.println(t.getName());
   try{
    activitiRule.getTaskService().complete(t.getId());
   }
   catch(Exception ex){
    ex.printStackTrace();
   }
}
System.out.println("END");
System.out.println("====================================================================");

}
</code>

When I try to complete them, I see the below exception.

<code>
org.activiti.engine.ActivitiException: UserTask should not be signalled before complete
at org.activiti.engine.impl.bpmn.behavior.UserTaskActivityBehavior.signal(UserTaskActivityBehavior.java:146)
at org.activiti.engine.impl.persistence.entity.ExecutionEntity.signal(ExecutionEntity.java:407)
at org.activiti.engine.impl.persistence.entity.TaskEntity.complete(TaskEntity.java:201)
at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:50)
at org.activiti.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:24)
at org.activiti.engine.impl.cmd.NeedsActiveTaskCmd.execute(NeedsActiveTaskCmd.java:59)
at org.activiti.engine.impl.interceptor.CommandInvoker.execute(CommandInvoker.java:24)
at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:57)
at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:37)
at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:40)
at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:35)
at org.activiti.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.java:175)
at org.activiti.MyUnitTest.test(MyUnitTest.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.activiti.engine.test.ActivitiRule$1.evaluate(ActivitiRule.java:126)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
</code>

Re: Skip expression on User Task

rhafner — Fri, 08 Jul 2016 12:25:41 GMT

Hi Hari,

What version of Activiti are you running this test case on? I am able to run the test case on Activiti 6 successfully and have validated the behavior is correct by tweaking the test case as shown below. FWIW, I am running the test case from within the Activiti test suite using the SkipExpressionUserTaskTest.

@Deployment
public void test2() {
HashMap<String,Object> mpvar = new HashMap<String,Object>();
mpvar.put("fname", "Hari");
mpvar.put("_ACTIVITI_SKIP_EXPRESSION_ENABLED", true);
ProcessInstance processInstance = runtimeService.startProcessInstanceByKey("TestSkipExp",mpvar);
System.out.println("STARTED PROCESS");
System.out.println("====================================================================================================");
assertNotNull(processInstance);

List<Task> tasks = taskService.createTaskQuery().taskAssignee("Hari").list();
assertEquals(1, tasks.size());
assertEquals("UT2", tasks.get(0).getTaskDefinitionKey());
for(Task t:tasks){
System.out.println(t.getTaskDefinitionKey() + " " + t.getName());
}

taskService.complete(tasks.get(0).getId());
assertNull(runtimeService.createProcessInstanceQuery().processInstanceId(processInstance.getId()).singleResult());

System.out.println("END");
System.out.println("====================================================================================================");

}

thanks,
Rob