Expression does not work for time cycle in timer event

[sensisdev]

Hi I am using Activiti 5.10

I have read the Activiti doco and it says the expression can be used for time cycle in timer event:
e,g.
     <timerEventDefinition>
      <timeDuration>${duration}</timeDuration>
    </timerEventDefinition>

My scenario is we want to read the time cycle from our configuration service instead of hard coding it.

My Activiti looks like this:

    <startEvent id="timerstartyelpendofdayreport" name="Timer Start Yelp End Of Day Report">
      <timerEventDefinition>
        <timeCycle>${configurationRetriever.getTimeCycle()}</timeCycle>
      </timerEventDefinition>
    </startEvent>

The configurationRetriever.getTimeCycle() will return cron expression string.

The problem is the activiti process can not be deployed and I have got the following error:

org.activiti.engine.ActivitiException: Failed to parse cron expression: ${configurationRetriever.getTimeCycle()}
    at org.activiti.engine.impl.calendar.CycleBusinessCalendar.resolveDuedate(CycleBusinessCalendar.java:37)
    at org.activiti.engine.impl.jobexecutor.TimerDeclarationImpl.prepareTimerEntity(TimerDeclarationImpl.java:128)
    at org.activiti.engine.impl.bpmn.deployer.BpmnDeployer.addTimerDeclarations(BpmnDeployer.java:182)
    at org.activiti.engine.impl.bpmn.deployer.BpmnDeployer.deploy(BpmnDeployer.java:149)
    at org.activiti.engine.impl.persistence.deploy.DeploymentCache.deploy(DeploymentCache.java:38)
    at org.activiti.engine.impl.persistence.entity.DeploymentManager.insertDeployment(DeploymentManager.java:42)
    at org.activiti.engine.impl.cmd.DeployCmd.execute(DeployCmd.java:59)
    at org.activiti.engine.impl.cmd.DeployCmd.execute(DeployCmd.java:31)
    at org.activiti.engine.impl.interceptor.CommandExecutorImpl.execute(CommandExecutorImpl.java:24)
    at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:42)
    at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(SpringTransactionInterceptor.java:42)
    at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:130)
    at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:40)
    at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:33)
    at org.activiti.engine.impl.RepositoryServiceImpl.deploy(RepositoryServiceImpl.java:54)
    at org.activiti.engine.impl.repository.DeploymentBuilderImpl.deploy(DeploymentBuilderImpl.java:106)
    at au.com.sensis.fabric.vendormanagement.process.yelp.Vendor20630FulfillmentEndOfDayReportTest.deploy(Vendor20630FulfillmentEndOfDayReportTest.java:76)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:76)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:195)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:63)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: java.text.ParseException: Unexpected character: $
    at org.activiti.engine.impl.calendar.CronExpression.storeExpressionVals(CronExpression.java:582)
    at org.activiti.engine.impl.calendar.CronExpression.buildExpression(CronExpression.java:360)
    at org.activiti.engine.impl.calendar.CronExpression.<init>(CronExpression.java:277)
    at org.activiti.engine.impl.calendar.CycleBusinessCalendar.resolveDuedate(CycleBusinessCalendar.java:32)
    … 48 more

Could anyone please give me a hand?

Many thanks

Sean

[frederikherema1]

The following code is responsible for getting the actual time-cycle out of the expression (org.activiti.engine.impl.jobexecutor.TimerDeclarationImpl):

if (executionEntity == null) {
      dueDateString = description.getExpressionText();
    }
    else {
      Object dueDateValue = description.getValue(executionEntity);
      if (dueDateValue instanceof String) {
        dueDateString = (String)dueDateValue;
      }
      else if (dueDateValue instanceof Date) {
        duedate = (Date)dueDateValue;
      }
      else {
        throw new ActivitiException("Timer '"+executionEntity.getActivityId()+"' was not configured with a valid duration/time, either hand in a java.util.Date or a String in format 'yyyy-MM-dd'T'hh:mm:ss'");
      }
    }

When used on a start-event, there is not yet an execution available, so the expression for the timeCycle is not evaluated, but rather just used as-is. This has been an issue with using expressions in start-forms as well, so I think this can be resolved in a similar way.
I've created a JIRA for this: https://jira.codehaus.org/browse/ACT-1415

[sensisdev]

Hi

Thank you very much and we will wait for Activiti 5.11 then.

Many thanks

Sean

[pondermuse1]

Hi,

I have just started learning about BPMN 2.0 with activiti-5.14 and have a process with a timer start event where I would like to make the timeCycle value configurable. If I make the value an expression like ${timeCycle}, how would I then go about setting the value at runtime?

Many thanks,
PM.

[pondermuse1]

Hello again,

I am still trying to figure out how a timer start event can be made configurable. Is this actually now possible in activiti version 5.14? If it isn't, are there any alternative methods to achieve this?

Thanks again,
PM.

[martin_grofcik]

Hi,

there is already testcase in the 5.15-SNAPSHOT for expressions in TimerStartEvent (I think it should work in 5.14 too).


    <process id="startTimerEventExample" name="Timer start event example">

        <startEvent id="theStart">
            <timerEventDefinition>
                <timeDate>${'2036-11-14T11:12:22'}</timeDate>
            </timerEventDefinition>
        </startEvent>   

        <sequenceFlow id="flow1" sourceRef="theStart" targetRef="receive"/>

        <receiveTask id="receive"/>

        <sequenceFlow id="flow2" sourceRef="receive" targetRef="theEnd"/>

        <endEvent id="theEnd"/>

    </process>

More info StartTimerEventTestRegards
Martin

[pondermuse1]

Hello martin,

Thanks for your reply. Indeed I can see from the test and other docs that it is possible to have variable expressions for <timeXXX> values. However, I was looking for more of a practical running example showing how the expression value could be changed (at runtime) and therefore triggering the engine to update the timer job's ACT_RU_JOB table row parameters, etc.

An example use case scenario being one where the scheduled task is executing every 5 minutes while timeCycle value is "R/PT5M", and some time later the task starts executing every 10 minutes when timeCycle value is updated to "R/PT10M".

Unfortunately I am not yet too familiarized with activiti's different APIs so I am not too sure how I could make this trigger take place in practice. i.e. Once the expression value changes, should I use the APIs to update the timer job's parameters in ACT_RU_JOB directly? Should I maybe use the APIs to delete the current job and then deploy a new one? Should I use the APIs to delete the model and then re-deploy the model? Or something else entirely?

Thanks again,
PM.

[jbarrez]

You would need to update the job fields and save it back.

That is not exposed in the current API, so you must create a custom Command, that updates the Job and saves it using the JobEntityManager, and pass that to the managementService.executeJob() method.

[njames]

Hi,
I agree that Martin's test case works, in that a constant expression is evaluated. However, I am trying to use the startEvent timerDefinitionExpression as the very first poster describes, and it doesn't work. Is this expected? I was expecting to have access to my Spring beans. I am using 5.15.1
<code>
    <startEvent id="timerstartevent1" name="Timer start">
      <timerEventDefinition>
        <timeCycle>${fooService.getStartTimeCycle()}</timeCycle>
      </timerEventDefinition>
    </startEvent>
</code>
Note that I am using the @Deployment annotation on my unit test, so the Spring environment is built and running before the deployment happens.

[frederikherema1]

What do you mean by "it doesn't work"? Any stacktraces?

Long time ago, I added a fix, so that the expressions get resolved even of there is no execution-context alive yet (eg. on a start-event, when the execution is about to start but doesn't exist yet) TimerDeclarationImpl:


// ACT-1415: timer-declaration on start-event may contain expressions NOT
    // evaluating variables but other context, evaluating should happen nevertheless
    VariableScope scopeForExpression = executionEntity;
    if(scopeForExpression == null) {
      scopeForExpression = NoExecutionVariableScope.getSharedInstance();
    }

In case the fooService is configured in the "beans" map (see user guide for details on bean-resolution in expressions depending on env), it will be usable. The value returned can be either a Date or a String…