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Data Object visibility [message #1066188]

Mon, 01 July 2013 09:09

Eclipse User

Hi,

I have a bpmn file with a lane and other BPMN components including Data Object component. The trouble is in a strange behaviour which manifests itself after I reopen the file which contains Data Object component. Sometimes some Data Object component is not shown "on" the Lane component (in which way was originaly been placed), but hidden "bellow" Lane component.

What might be the reason for this kind of behaviour, and is there a way to keep Data Object in its place?

Re: Data Object visibility [message #1066191 is a reply to message #1066188]

Mon, 01 July 2013 09:28

Eclipse User

Data Objects are subclasses of FlowElement, but a Lane may only contain FlowNodes (also a subclass of FlowElement), therefore a Lane may not contain Data Objects. The fact that a Data Object appears to move along inside a Lane when you first create it by dropping it onto a Lane, is actually a bug Sad

Can you please file a bug report for this behavior?

Thanks for testing!
Bob

Re: Data Object visibility [message #1066198 is a reply to message #1066191]

Mon, 01 July 2013 10:02

Eclipse User

Thanks for your reply,

Is there a way to include Data Object element in a process diagram? I tried to find this information in BPMN standard, but haven't found clear answer to this question.

I will file a bug report for strange behavior of Data Object inside a Lane.

Re: Data Object visibility [message #1072451 is a reply to message #1066198]

Mon, 22 July 2013 15:53

Eclipse User

Hi Bob,

I have the same problem on a collaboration pool. When I re-opened my model the process disappeared behind the pool.

Do you want me to paste the model here?

In the mean time, do you know if there is a workaround (like editing the xml file) to fix the problem and continue working on the model?

Thanks!

EDIT: I tried to move stuff around in the BPMDI element (I moved a pool declaration up) and the problem is fixed (temporarily at least).

[Updated on: Mon, 22 July 2013 15:57] by Moderator

Re: Data Object visibility [message #1072761 is a reply to message #1072451]

Tue, 23 July 2013 08:47

Eclipse User

Hmm...instead of:

"When I re-opened my model the process disappeared behind the pool"

did you mean to say this instead?

"When I re-opened my model the Data Object disappeared behind the pool"

Again, a "pool" as you know, is a BPMN2 Participant element which can not be a container for Data Objects so, technically this is not unexpected behavior.

That said, I can make some adjustments to the editor so that Pools and Lanes are always pushed to the bottom of the Z-order.

Can you please file a bugzilla for this enhancement request so we can track this? I would like to publish a new build (which will be version 0.2.7) by the end of this week, so if you can file this enhancement request soon-ish, it will go into that build.

Thanks!
Bob

Re: Data Object visibility [message #1072845 is a reply to message #1072761]

Tue, 23 July 2013 12:25

Eclipse User

Actually I said it right, the process disappeared and by "process" I actually mean flow nodes and data objects. I was left with only the pool showing control flow arrows.

As I said, moving DI element around in the XML file fixed the problem. And I am able to replicate the bug. Actually moving the participant's shape after the flow nodes in the xml file causes the problem. I guess this has to do with sequential order in which elements are drawn (elements drawn after get a higher z-index).

As regarding your comment about Data Objects, the way I understand it is that Data Object are contained by the process. In a collaboration we have a process for each participant so in practice the data object end up being contained by the participant, right?

I will file a bugzilla right away and I'll paste my process that causes the bug.

Thanks.

Re: Data Object visibility [message #1072882 is a reply to message #1072845]

Tue, 23 July 2013 14:01

Eclipse User

wellll...yes and no Smile

The Participant has a Process reference which, in theory, could change. This would mean that the entire contents of the "pool" would have to be swapped if the Process reference is changed. I'm not 100% convinced (yet) that this is the right thing to do, and for that reason the Participant.processRef is not changeable directly in the editor.

But I concede your point that Data Objects need to be rendered as contained children of pools. Please go ahead and file that bug report, and we'll try to address it as quickly as possible.

Thanks!
Bob

Re: Data Object visibility [message #1072902 is a reply to message #1072882]

Tue, 23 July 2013 14:42

Eclipse User

Hi Bob,

Here the bug filed: https://bugs.eclipse.org/bugs/show_bug.cgi?id=413563

I can't see either a use case where one would want to change the process ref of a participant in a visual modelling tool.

Thanks for your help!

Re: Data Object visibility [message #1072918 is a reply to message #1072902]

Tue, 23 July 2013 15:23

Eclipse User

Bob, I have a follow-up question regarding data objects.

While modelling a process, I realized you implemented the data object referencing feature: when I try to add a data object to my model, it asks me if I would like to create a new one or reference an existing data object instead. However this behaviour doesn't seem to be implemented when modelling a collaboration. Is that correct? If so, do you plan on implementing it?

Re: Data Object visibility [message #1072972 is a reply to message #1072918]

Tue, 23 July 2013 17:21

Eclipse User

Hmmm, that sounds like an omission. It should work the same for any BPMN2 diagram type. Unless of course I forgot to add DataObjectReference to the <modelEnablements> list in the plugin for Collaboration diagrams. I'll take a look - should be an easy fix.

Re: Data Object visibility [message #1073989 is a reply to message #1072972]

Thu, 25 July 2013 18:36

Eclipse User

Ok then continuing the same debate:

According to BPMN specs, a DataObject must be contained by a Process. A DataObjectReference are a way to reuse DataObject in the same diagram.

Now my question: can a DataObjectReference in a process p1 (say referenced by participant A) references a DataObject from process p2 (referenced by participant B) ?

In other words, in a collaboration should a DataObjectReference cross process limits or should it be restricted to DataObjects of the same process (participant)? Going through the specs, I don't see anything preventing that behaviour but, as we know, BPMN specs are very ambiguous when it comes to DataObjects...

I wish I could use it that way (crossing process limits) because it serves my purpose. But I don't know how you are planning to implement it... The modeller did not complain after editing the BPMN file to reference DataObjects from other processes (I was able to open my model with no problem) so at least there is no contradiction with the metamodel.

Thanks!

Re: Data Object visibility [message #1074038 is a reply to message #1073989]

Thu, 25 July 2013 21:13

Eclipse User

Funny you should mention this, because I came across the same dilemma Wink

I decided that as long as references to DataObject don't cross file boundaries, they should be allowed; that is a DataObjectReference defined in one Process may reference DataObjects defined in any other Process.

Make sense? That's what I thought - I'm not sure either but that's how it is implemented at the moment.

Re: Data Object visibility [message #1074443 is a reply to message #1074038]

Fri, 26 July 2013 16:09

Eclipse User

Makes much sense to me. But again I am biased by my project and implementing it that way is perfect for me. Smile

Going through BPMN specs, I couldn't see anything advising against it. However I could envision many use cases where such behaviour would be beneficial (two companies collaborating by exchanging some XML data conforming to the same schema/ontology, it wouldn't make much sense to create a copy of the same object but one should rather reference the original). It also appears more clear if you consider DataStore and DataStoreReference.

Hope though that OMG will clarify this someday.

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