Start a process in plain Java

Calling a Sub-Process from plain Java has become much simpler since Axon.ivy 6.3. There is now a nice fluent API to invoke a process and get back the the resulting data. The entry point is here: ch.ivyteam.ivy.process.call.SubProcessCall

You can find an example in the ConnectivityDemos where a Java REST-Service implementation starts a Process in the engine. See ConnectivityDemos -> com.axonivy.connectivity.rest.provider.ApprovalService.create(String, String, String)

ITask task = SubProcessCall.withPath("rest/createApproval")
                .withParam("title", title)
                .withParam("description", description)
                .call()
                .get("approvalTask", ITask.class);

Alternative (with System Events)

I do not like the search of the correct process.
To jump from plain Java in a Ivy process, I recommend an alternative way with System Events.

You have to change your process a little. Add a "event start" element instead the normal "request start" element. Or you can put it also next to the process start.

Write your one event bean like this:

public class SystemEventSubscriber extends AbstractProcessStartEventBean {...

Or you could use the example from ivyhacker

The java code to jump in the process looks nicer:

IApplication app = Ivy.wf().getApplication();
SystemEvent<E> event = 
  new SystemEvent<E>(SystemEventCategory.THIRD_PARTY, [identifier-string], [object of type E]);
app.sendSystemEvent(event);

Like this, you are able to jump to any start event with an identifier string, and you could hand out a parameter as an object type of your choice. For further information read this entry ivyhacker.

Conclusion:

• (-) Small process changes
• (+) Posibility to jump to any process step (activity)

Since Axon.ivy 4.3 you can start sub processes like this:

ISubProcessStart object;
if (className != null) {
    object = getSubProcess(className);
    if (object == null) {
        setProcessDataField(context, STATUS_MESSAGE_PROPERTY, StatusMessage.MESSAGE_TYPE_ERROR);
        return in;
    }
    results= SubProcessRunner.exec(object, param);
}



private ISubProcessStart getSubProcess(String className){

    //Create filter.
    SubProcessSearchFilter filter = SubProcessSearchFilter.create()
            .setProcessPathPattern(className) 
            .toFilter();

    //Result list of processes. picking first only.

    List<ISubProcessStart> foundSubProcesses = SubProcessRunner.findSubProcessStarts(filter);
    if (foundSubProcesses.isEmpty()) {
        return null;
    }
    return foundSubProcesses.get(0);
}

You need to handle the exceptions within the subprocesses. You can't handle it to the parent class.