topic Executing Asynchronous Processes from exception point in Alfresco Archive

Executing Asynchronous Processes from exception point

sankardunga — Fri, 03 Jan 2014 13:29:54 GMT

Hello,I have multiple service tasks in my process. I'm not able to re-execute the job from exception point of particular task.I'm using ''managementService.executeJob(id)'' for executing the particular job, here it is executing the process from service task1.How to run the job from the exeception po

Re: Executing Asynchronous Processes from exception point

trademak — Sun, 05 Jan 2014 21:04:51 GMT

Hi,

If you want to run it from the exception point, is that a service task as well?
Then you could make that service task asynchronous.

Best regards,

Re: Executing Asynchronous Processes from exception point

sankardunga — Mon, 06 Jan 2014 05:36:26 GMT

Thanks for reply…
Ya, I made it asynchronous, This the format I have written in my process
"<serviceTask id="id" name="testTask" activiti:async="true" activiti:expression="#{test.processEvent(data)}"></serviceTask>"

It is creating a job entry in the data table whenever exception occurs, and after that I'm trying to re execute this job using
''managementService.executeJob(id)''
Its starting the process from service task one instead . Is there any other api or sysntax modification required to start the service from the exception point ?

Re: Executing Asynchronous Processes from exception point

sankardunga — Mon, 06 Jan 2014 10:50:09 GMT

Here I'm using my own exception handlers, I don't whether it ll be the reason for this problem or not. If that is the reason, please give me a way to handle the exceptions. Please help me in scenario…

Re: Executing Asynchronous Processes from exception point

jbarrez — Mon, 06 Jan 2014 12:31:18 GMT

To run the job automatically, you will need to start the job executor (it's a configuration option). No need to call the managementService then when it's running.

Re: Executing Asynchronous Processes from exception point

sankardunga — Mon, 06 Jan 2014 13:34:00 GMT

Hi jbarrez,
My question is not about 'How to run jobs'. If it is possible can you please give me the relative answer.

Re: Executing Asynchronous Processes from exception point

jbarrez — Wed, 08 Jan 2014 08:23:10 GMT

> My question is not about 'How to run jobs'. If it is possible can you please give me the relative answer.

Excuse me. I was confused by your hard to follow explanation of your problem.

>Its starting the process from service task one instead . Is there any other api or sysntax modification required to start the service from the exception point ?

Hence my response. If you have an exception in a service task that is asynchronous, it will be in a job with a retries count 0. You will need to execute the job yourself at that point. But then again, I really don't understand the problem you are describing.

Re: Executing Asynchronous Processes from exception point

sankardunga — Thu, 09 Jan 2014 06:32:45 GMT

Thanks jbarrez.

I understood the asynchronous process flow, its going fine. And I faced issues because of two process engines running at same time in my system.

And is there any way to read the runtime variable data and also serialized data from act_ge_bytearray?
I mean like "SELECT * FROM act_ru_variable WHERE PROC_INST_ID_ = ?"

Re: Executing Asynchronous Processes from exception point

frederikherema1 — Thu, 09 Jan 2014 11:07:01 GMT

Variables can be read through the API, using runtimeService.getVariables(executionId) or inside a JavaDelegate/listener, use DelegateExecution.getVariables(). The returned map contains all variables, including deserialized POJO's and byte-arrays form ACT_BE_BYTEARRAY.

Re: Executing Asynchronous Processes from exception point

sankardunga — Fri, 10 Jan 2014 06:51:51 GMT

Thanks man, its very helpful to me.
One more doubt, how can I pass my own exceptions messages to the activiti table. Right now when some exception occurs it is placing activiti exception message in database(ie in ACT_RU_JOB table) instead of user-defined exception message. I mean the following exception is placing when exception occurs in service task,
"Error while evaluating expression: #{server.processEvent(data)}"
but I want to place my own eception, How can I achieve this ?

Re: Executing Asynchronous Processes from exception point

frederikherema1 — Fri, 10 Jan 2014 10:34:35 GMT

Depends on where the exception is thrown… It looks like an exception occuring as part of a service-task execution. You won't be able to alter that message. If you use a java-delegate, you can throw any exception you want from within the execute() method.

Re: Executing Asynchronous Processes from exception point

sankardunga — Fri, 10 Jan 2014 11:01:36 GMT

Thanks frederikheremans.
Ya, I'm trying to throw my own exception in the service task which is not implementing java-delegate.
And here I'm looking for an option to store my custom exception in Database. Isn't it possible at all in activiti without using java-delegate.

Can you please suggest me some approach here ?

Re: Executing Asynchronous Processes from exception point

trademak — Fri, 10 Jan 2014 11:27:00 GMT

Are you using an expression or delegate expression then? If it throws a custom exception, this exception should be stored in the job exception message by default. What do you see in the job exception message?

Best regards,

Re: Executing Asynchronous Processes from exception point

sankardunga — Fri, 10 Jan 2014 11:52:14 GMT

I'm using expression but not delegate expression. I'm getting following value in ACT_RU_JOB table
                 " Error while evaluating expression: #{createServer .processEvent(data)} "

Here I'm not implementing the JavaDelegate behavior to my class.
My class snippet looks this

     public class CreateServer extends AbstractHandler {
        @Override
protected void execute(IEvent event) throws ActivitiException {
CreateServer createServer = null;
if(event instanceof CreateServer ){
   createServer = (CreateServer ) event;
   myMethod(createServer );    //Custom Exception thrown in this method
}
}
      }

can I store my custom exception message here ?

Re: Executing Asynchronous Processes from exception point

frederikherema1 — Fri, 10 Jan 2014 12:33:56 GMT

The delegate expression will always be executed by JUEL. Any exceptions that occur there will be wrapped. You could use the cause of the exception, found in the referenced stacktrace byte-array entity. However, the exception-message in the ACT_RU_JOB row wil still be the message of the outer JUEL-exception.

An option to modify the message is to override the org.activiti.engine.impl.jobexecutor.DefaultFailedJobCommandFactory class, and return a custom DecrementJobRetriesCmd that populates the exception-message based on what you want. Currently, it does this:


 if(exception != null) {
      job.setExceptionMessage(exception.getMessage());
      job.setExceptionStacktrace(getExceptionStacktrace());
    }

Plug your custom implementation of the org.activiti.engine.impl.jobexecutor.DefaultFailedJobCommandFactory in the "failedJobCommandFactory" property of the process engine configuration.

Re: Executing Asynchronous Processes from exception point

sankardunga — Thu, 16 Jan 2014 07:42:03 GMT

Thanks frederikheremans. Now I gonna ask one poor doubt …
Do I need to implement 'FailedJobCommandFactory' interface in my exception class to override the "getCommand((jobId, exception)" method ?
Any other configuration is required ?
Please help me where & how can override this class ?

Re: Executing Asynchronous Processes from exception point

frederikherema1 — Thu, 16 Jan 2014 08:27:23 GMT

You can extend the DefaultFailedJobCommandFactory and override the getCommand() method, indeed. No other configuration required, other than setting this factory on your configuration.

Re: Executing Asynchronous Processes from exception point

sankardunga — Thu, 16 Jan 2014 09:16:33 GMT

This is my exception class and I override the "DefaultFailedJobCommandFactory " class.
    public class ValidateUpdateServerRequestException extends DefaultFailedJobCommandFactory {
        private static final long serialVersionUID = -5681708327398999347L;
   public Command<Object> getCommand(String jobId, Throwable exception) {
       return new DecrementJobRetriesCmd(jobId, exception);
   }
    }

How to do factory bean configuration in xml ?
Can please give me example ?

Re: Executing Asynchronous Processes from exception point

frederikherema1 — Thu, 16 Jan 2014 11:02:00 GMT

Use the property "failedJobCommandFactory" to set a reference to your factory:


 <property name="failedJobCommandFactory">
   <bean class="com.whatever.ValidateUpdateServerRequestException" />
 </property>
[code]

Re: Executing Asynchronous Processes from exception point

sankardunga — Fri, 17 Jan 2014 06:36:03 GMT

Ya, I have override the class & set the configuration. It is coming to the overridden class. But still I'm getting the same 'ActivitiException stacktrace' with Throwable class type parameter of getCommand() method instead of whatever I'm throwing from my class.

I'm not getting from where it is setting this exception ?