BPMN extension using artifacts

[Graham Crosmarie]

Hello everybody,

BPMN 2.0 specifications clearly specify : "A modeler or modeling tool
MAY extend a BPMN diagram and add new types of Artifacts to a
Diagram."

If I want to add some new artifacts to a BPMN Editor, will I necessary
have to modify the BPMN 2.0 xsd ?

Here is my thought :
I have been seeking through the BPMN extension mechanism which is
mostly in my opinion the possibility to add foreign attributes and
foreign objects to any Base Element. But this mechanism only allows me
to create "subclasses" of the existing artifacts i.e. extension for
Group, Association or Text Annotation. If I want to add to my editor a
totally new type of Artifact, I will have to add this new object to
the BPMN 2.0 xsd.

So I think that there is either a lack in BPMN 2.0 (a special
extension mechanism for artifacts) or a contradiction (if you add new
artifacts, you will not be able to serialize them to xml).
In both case I am wondering if extending BPMN 2.0 using artifacts is a
good idea.

Thanks in advance for your answers,

Graham Crosmarie
R&D engineer
Petals Link (http://www.petalslink.com/)

[Bruce Silver]

If you look at the schema, extensionElements is a child of tArtifact, so
this is already in the spec. You would just put your extensions under that
child in your own namespace. You need to do something in BPMNDI as well.

Bruce Silver
Principal, Bruce Silver Associates/BPMessentials
br...@brsilver.com
www.brsilver.com
+1 831.685.8803

Hello everybody,

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[Graham Crosmarie]

First of all, I thank you for your answer. However I have something to
add :

You are right : tArtifact allows extension via extensionElements
because it extends tBaseElement like most BPMN types.
But tArtifact is also abstract, so if I want to add a new Artifact
(using extensionElements), I first have to "instantiate" an element as
one of the subtypes of tArtifact : tGroup, tAssociation ot
tTextAnnotation.
Then I can add the extensionElements in this instance.

So maybe my question was : should tArtifact really be abstract ?

I think it might be concrete like tAuditing and tMonitoring which are
explicitly defined in the specifications as a way to "leverage the
BPMN
extensibility mechanism". These two objects really allow extensibility
because they do not force to choose a subtype as a "place" for the
extension.

Graham Crosmarie
R&D engineer
Petals Link (http://www.petalslink.com/)