Multi-instance collection and triggerable tasks

Flowable Engine
1

Hi,

I have a process containing a service task with multiInstanceLoopCharacteristics as follows:

<bpmn:serviceTask id="Activity_1gylrrb" name="Read File" flowable:extensionId="fileReaderTask"
                      flowable:async="true" flowable:triggerable="true"
                      flowable:class="com.acme.platform.workflow.engine.ServiceTaskImpl">
      <bpmn:incoming>Flow_009cumx</bpmn:incoming>
      <bpmn:outgoing>Flow_0s9qje0</bpmn:outgoing>
      <bpmn:multiInstanceLoopCharacteristics isSequential="true" flowable:collection="workersList" flowable:elementVariable="worker" />
</bpmn:serviceTask>

The service task calls out to another system over REST to perform the task. Once I get the reply I trigger the task via runtimeService.triggerAsync (also tried plain trigger).
What I’m seeing is that the engine is not progressing to the next iteration of the loop and it seems to be stuck on the execution of the first task.
I haven’t seen any examples of a multi-instance collection being used with triggerable tasks. Is this supported ? I managed to get something similar working with a cardinality based loop and a subprocess but not with a collection and no sub-process as above.

2

Right, so for some reason I had to do the following in my delegate class and force an execution leave. This seems to get the loop going again:

public class ServiceTaskImpl extends ServiceTaskJavaDelegateActivityBehavior {

  @Override
  public void execute(final DelegateExecution execution) {
    ...
  }

  @Override
  public void trigger(final Context context) {
    trigger(context.getExecution());
  }

  @Override
  public void trigger(final DelegateExecution execution, final String signalEvent, final Object signalData) {
    trigger(execution);
  }

  private void trigger(final DelegateExecution execution) {
    leave(execution);
  }
}