topic Re: Support for the complex gateway in Alfresco Archive

Support for the complex gateway

b_schnarr — Wed, 22 Apr 2015 09:31:04 GMT

Hello at all,I would like to know if there are plans to support the complex gateway in engine, designer and modeler?In addition, the same question is true for Compensation Boundary Events, Compensation Intermediate Throwing Events and Compensation Handlers.Thanks for your answersBest regardsBen

Re: Support for the complex gateway

b_schnarr — Fri, 24 Apr 2015 11:00:12 GMT

I added a ticket: https://activiti.atlassian.net/browse/ACT-4003

Re: Support for the complex gateway

trademak — Fri, 24 Apr 2015 12:41:26 GMT

Hi Ben,

What kind of functionality would like to see in the complex gateway?
Have the logic implemented in a Java class or expression that you can define, or something else.
Do you use a lot of compensation events in your processes? If there's enough interest in the community we can definitely look into this.

Best regards,

Re: Support for the complex gateway

b_schnarr — Mon, 27 Apr 2015 09:02:59 GMT

Hi Tijs, thanks for your feedback.

Concerning the complex gateway, I would like to refer to the following workflow patterns which imho only can be implemented using a complex gateway:

http://www.workflowpatterns.com/patterns/control/advanced_branching/wcp9.php
http://www.workflowpatterns.com/patterns/control/new/wcp28.php
http://www.workflowpatterns.com/patterns/control/new/wcp30.php
http://www.workflowpatterns.com/patterns/control/new/wcp31.php
http://www.workflowpatterns.com/patterns/control/new/wcp32.php

For those usecases, you need a complex gateway in this way: The modeler can add an expression to the Complex gateway that will determine
how many Tokens must arrive from its incoming Sequence Flow, before a Token will be sent down its outgoing Sequence Flow. Any additional Tokens that arrive later will be blocked at the Gateway (a complex gateway provides the the N out of M Join pattern)

Concerning the compensation events: I am of the opinion that business rollbacks are very important in a productive environment. Those BPMN constructs are not too exotic and should therefore be implemented to ensure a maximum of modelling possibilities.

Best regards
Ben

Re: Support for the complex gateway

jbarrez — Tue, 28 Apr 2015 18:43:50 GMT

We haven't heard much demand for the complex gateway, hence why it hasn't been added before.
An n-out-of-m join is actually not that hard to do. The 'blocked' bit is a bit trickier.

The spec also mentions 'If tokens arrive later on the two remaining Sequence Flows, those tokens cause a reset of the Gateway and new token can be produced on the outgoing Sequence Flows. To determine whether it needs to wait for additional tokens before it can reset, the Gateway uses the synchronization semantics of the Inclusive Gateway.'

This is rather hard, as it implies keeping state somehow in the gateway.

I'm actually like the idea of Tijs (having a Java-based gateway), I think that would solve already a lot of use cases.

Re: Support for the complex gateway

b_schnarr — Tue, 28 Apr 2015 19:14:29 GMT

does that mean that this will land on your roadmap?

Re: Support for the complex gateway

jbarrez — Tue, 28 Apr 2015 19:29:06 GMT

Depends. I'm not sure about the complex gateway actually. It has some fuzzy semantics which aren't clear to me yet.

A java based gateway is something else. Although you can do it already today with an ActivityBehaviour (even the n-out-of-m), there is probably a simpler interface specifically targeted to gateways and choosing sequence flow.

Re: Support for the complex gateway

b_schnarr — Wed, 29 Apr 2015 07:31:34 GMT

Does a "java based gateway" mean that you cannot model this complex gateway with a symbol in the modeler and designer? Would be great so see a "complex gateway" in upcoming releases.

Re: Support for the complex gateway

jbarrez — Thu, 07 May 2015 12:20:44 GMT

That doesn't really matter, we can add a complex gateway icon to anything and still make a java class mandatory 😉

Re: Support for the complex gateway

b_schnarr — Thu, 07 May 2015 12:24:09 GMT

ok, would be great to see the complex gateway soon. For my thesis at university, I currently make an analysis how the Van der Aalst Patterns can be implemented using Activiti. If you would add support for the complex gateway, for Ad-hoc subprocesses and for conditional events, you could add the slogan to Activiti: "We support all Workflow-Patterns" 😉

Re: Support for the complex gateway

jbarrez — Thu, 07 May 2015 13:31:39 GMT

I remember (long, long ago, jbpm 3 days) that we tried to do that (I believe that Tom met with prof. Van der Aalst), but back in the day a 'java fallback' was not considered as covering the pattern.

Re: Support for the complex gateway

b_schnarr — Wed, 13 May 2015 07:28:34 GMT

Maybe, this here could be helpful?
https://github.com/intalio/bpmn2/blob/master/org.eclipse.mdt.bpmn/src/org/eclipse/mdt/bpmn/impl/ComplexGatewayImpl.java

The way to support 100 % of all Workflow-Patterns is not that far. Look at this here: https://activiti.atlassian.net/browse/ACT-4015

Re: Support for the complex gateway

trademak — Wed, 13 May 2015 12:12:53 GMT

We understand the functionality of the complex gateway. Our goal is to support the constructs mentioned in ACT-4015, it will just take some time to get there.

Best regards,

Re: Support for the complex gateway

b_schnarr — Thu, 21 May 2015 12:23:57 GMT

thanks for this information, Tijs. Are those missing constructs already priorized on the roadmap?

Re: Support for the complex gateway

jbarrez — Thu, 28 May 2015 15:13:14 GMT

Current priority is Activiti 6, and it will be for a while. So don't get your hopes up.