[jwt-dev] About the JWT Model

[Pierre Vigneras <pierre.vigneras@xxxxxxxx>]

Dear all,

recently, we submitted a small modification of the JWT Model that introduces 
two new elements: AndControlNode and XorControlNode (initially called 
XorGateway and AndGateway).

Please, see bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=256916

The main point to get is the following:

Since our modifications, the EMF model contains the following elements:

ControlNode
	<- XorControlNode
		<- DecisionNode
		<- MergeNode
	<- AndControlNode
		<- ForkNode
		<- JoinNode

We feel that leaf nodes (DecisionNode, MergeNode, ForkNode and JoinNode) are 
both very UML specific and redundant, i.e, not required. Obviously, a  
forkNode is just an AndControlNode with multiple outgoing transition. A 
MergeNode is just an XorControlNode with multiple incoming transition. Note 
that BPMN allows a node to have multiple incoming and outgoing transition. In 
this case the semantic for the Split and Synchronization is the same: either 
an Xor or an And. Currently the constraints on the number of transitions 
(either incoming or outgoing) are already in the controller (editpart) of the 
related model (e.g.: ForkEditPart for the ForkNode). So, using the new model, 
the behavior of the ForkNode is given by its father element, AndControlNode. 
Nothing else is provided by the model itself.

We expect JWT to get wide community adoption, and therefore, new tools based 
on JWT and on this EMF model to be developed. We would like those tools to 
support any design (UML, BPMN, whatever) developed with any JWT-based 
designer as long as those tools deal with the model only (for example 
simulator, monitors and so on). We guess that developers of those tools may 
naturally use leaf nodes of the model (ForkNode, JoinNode, and so on) instead 
of their fathers (*ControlNode). And we guess that it may lead to 
compatibility problem between different tools.

So the question is: can't we remove those leaf nodes?

 We understand that it will have some impact on JWT but most of the logic is 
already in controllers anyway (editparts). Leaf nodes do not contain any 
information by themselves (as far as I can see, tell me if I am wrong).

What are your opinions at JWT levels?
What are the opinions of other contributors? (JBoss particularly)

Regards.
-- 
Pierre Vignéras
Bull, Architect of an Open World TM
*BPM Team*, Bull R&D
1, rue de Provence
38130 Echirolles (France)
Direct Line: +33-4-76-29-74-06

*Orchestra*, The BPEL open source project: http://orchestra.ow2.org
*Bonita*, The XPDL open source project: http://bonita.ow2.org