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How to deal with Implicit-Or Split limitations [message #5933]

Tue, 04 October 2016 17:32

kong
Messages: 90
Registered: December 2011

Member

To illustrate a workflow requirement I am struggling with, let's look at the workflow as described in http://www.tonymarston.net/php-mysql/workflow.html#sample:

http://www.tonymarston.net/php-mysql/workflow-order-fulfillment.png

As an example, if for whatever reasons a new business requirement is: Allow order cancellations by customers anytime after charging credit card but before shipment (and of course refund payments minus a handling fee as part of the order cancellation procedure). This requirement could be modeled in a straight forward manner like this:

https://s18.postimg.org/kg0rjfk8p/workflow_updated.png

However, such workflow would require multiple Implicit-Or splits without any timed transitions as currently required in Radicore. So, how should one go about thinking, modeling and implementing such a business requirement in Radicore workflow?

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Re: How to deal with Implicit-Or Split limitations [message #5936 is a reply to message #5933]

Wed, 05 October 2016 04:22

AJM
Messages: 2388
Registered: April 2006
Location: Surrey, UK

Senior Member

As an implicit OR split can only have 2 outbound arcs you will have to introduce another place after D which effectively says "Cancel or Continue". So as soon as the Shipment (Continue) tales place the Cancel operation then becomes disabled.

Tony Marston
http://www.tonymarston.net
http://www.radicore.org

[Updated on: Wed, 05 October 2016 07:26]

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Re: How to deal with Implicit-Or Split limitations [message #5938 is a reply to message #5936]

Wed, 05 October 2016 07:32

AJM
Messages: 2388
Registered: April 2006
Location: Surrey, UK

Senior Member

Note that an implicit OR split can only have two arcs, and one of the transitions MUST have a timer as a trigger. If you want more than one arc, or conditions without a timer, then you MUST use an explicit OR split.

Tony Marston
http://www.tonymarston.net
http://www.radicore.org

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Re: How to deal with Implicit-Or Split limitations [message #5942 is a reply to message #5938]

Wed, 05 October 2016 15:55

kong
Messages: 90
Registered: December 2011

Member

Not sure I grasp this completely, so based on what I understand here are 2 solutions that approximate the required behavior.

Solution 1:

https://s9.postimg.org/5lszmq0hb/workflow_updated1.png

Solution 2:

https://s12.postimg.org/fojan14n1/workflow_updated2.png

Out of these 2, I think that the second solution is closer to the required behavior.
Any other solutions to get even closer to the business requirement?

[Updated on: Wed, 05 October 2016 16:17]

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Re: How to deal with Implicit-Or Split limitations [message #5945 is a reply to message #5942]

Wed, 05 October 2016 18:30

AJM
Messages: 2388
Registered: April 2006
Location: Surrey, UK

Senior Member

Your requirement is that at the shipping stage there should be a choice - either ship or cancel. When one of these choices is made it disables the other. You must build this choice into your workflow using an Explicit OR split.

Tony Marston
http://www.tonymarston.net
http://www.radicore.org

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Re: How to deal with Implicit-Or Split limitations [message #5947 is a reply to message #5945]

Wed, 05 October 2016 19:42

kong
Messages: 90
Registered: December 2011

Member

Yes, I think I did that in both solutions. In solution 1 I added an Explicit-Or to allow choice between cancel or continue before the "Ship" transition. In solution 2, I made all the transitions between "credit card charge" and "ship" into Explicit-Or with a 'cancel' arc, so that order could be canceled at any stage. Am I missing something?

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Re: How to deal with Implicit-Or Split limitations [message #5949 is a reply to message #5947]

Thu, 06 October 2016 07:21

AJM
Messages: 2388
Registered: April 2006
Location: Surrey, UK

Senior Member

The more I read this post the more I realise that what you are trying to do is perfectly logical, yet my implementation does not allow it. I have gone back to my original reference material at http://martinfowler.workflowpatterns.com/documentation/docum ents/vanderaalst98application.pdf and I now see that my implementation is too restrictive. I shall start work on modifying it so that an Implicit-OR-split can have more than 2 arcs, and that it need not have a transition with a TIMER trigger. I will post the updated code here as soon as I can.

Tony Marston
http://www.tonymarston.net
http://www.radicore.org

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Re: How to deal with Implicit-Or Split limitations [message #5951 is a reply to message #5949]

Thu, 06 October 2016 12:53

kong
Messages: 90
Registered: December 2011

Member

Actually, after reviewing the source code of the workflow engine, I think it already supports implicit-or splits with multiple arcs without requirement for having one timed transition following it.

You just have to remove this constraint from wf_workflow_s01.class.inc, function _cm_validateUpdate:

                        if ($arc['arc_count'] > 2) {
                            // "Too many arcs of type 'OR-split (Implicit)' at place '$place_name'"
                            $errors[] = getLanguageText('e0065', $place_name);
                        } // if

BTW, that paper in your link is written by the same professor Wil van der Aalst who built the website that I linked here http:// radicore.org/fud/index.php?t=msg&th=891&goto=5940&am p;#msg_5940.

[Updated on: Thu, 06 October 2016 13:00]

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