RE: Petri net to BPEL model transformation > How to fi

In order to transform one document to another, it is first necessary to understand how the nodes in the original document relate to the nodes in the output document. Nothing in your model documents suggests to me exactly what those relationships might be.

It appears that between pairs of <place> elements there is exactly one <transition> element ( P---T---P) judging by comparing the @id values of the <place> and <transition> elements to the values of the <from> and <to> children of the <arc> elments.

Looking at your desired output, I hypothesize that each <invoke> element is derived from a <transition> element, but beyond that, I'm at a loss to describe any other relationship to the source document.

Please describe what the relationships are between elements in the souce document and elements in the output document.


Charles Knell
cknell@xxxxxxxxxx - email



-----Original Message-----
From:     stgn@xxxxxxx
Sent:     Mon, 04 Sep 2006 09:38:03 +0200
To:       xsl-list@xxxxxxxxxxxxxxxxxxxxxx
Subject:   Petri net to BPEL model transformation > How to find patterns?

Hello

How can I find/describe patterns in a Petri net graph with XSLT?

For instance a sequence, a concurrency, AND-split, AND-join, OR-split,
OR-join or a while loop.

Below you see a Petri net model (source model) which I would like to
transform into a BPEL model (target model).

Can you tell me what the corresponding XSLT code would look like?

My problem is to find patterns in a graph representation (Petri net)
and to transform them into a tree representation (BPEL). It might be
that such a transformation is not possible with the Petri net example
given below or that the Petri net XML would need further information
(for example an attribute attached to a transition saying "this is the
start of an AND-split").

I am grateful for any hints. If you need any further information to
solve the problem, please let me know.

Regards
Sagi

--------------------
source model
--------------------
<?xml version="1.0"?>
<petrinet>

	<!-- start of Petri net -->
	<place id="1"></place>
	<transition id="2"></transition>

	<!-- upper flow of concurrency -->
	<place id="10"></place>
	<transition id="11"></transition>
	<place id="12"></place>
	<transition id="13"></transition>
	<place id="14"></place>

	<!-- lower flow of concurrency -->
	<place id="20"></place>
	<transition id="21"></transition>
	<place id="22"></place>

	<!-- end of Petri net -->
	<transition id="3"></transition>
	<place id="4"></place>

	<!-- arcs connecting places and transitions -->
	<arc>
		<from>1</from>
		<to>2</to>
	</arc>
	<!-- next 2 arcs define an AND-split -->
	<arc>
		<from>2</from>
		<to>10</to>
	</arc>
	<arc>
		<from>2</from>
		<to>20</to>
	</arc>
	<!-- upper flow of concurrency -->
	<arc>
		<from>10</from>
		<to>11</to>
	</arc>
	<arc>
		<from>11</from>
		<to>12</to>
	</arc>
	<arc>
		<from>12</from>
		<to>13</to>
	</arc>
	<arc>
		<from>13</from>
		<to>14</to>
	</arc>
	<!-- lower flow of concurrency -->
	<arc>
		<from>20</from>
		<to>21</to>
	</arc>
	<arc>
		<from>21</from>
		<to>22</to>
	</arc>

	<!-- next 2 arcs define an AND-join -->
	<arc>
		<from>14</from>
		<to>3</to>
	</arc>
	<arc>
		<from>22</from>
		<to>3</to>
	</arc>
	<arc>
		<from>3</from>
		<to>4</to>
	</arc>
</petrinet>



--------------------
target model
--------------------
<?xml version="1.0"?>

<process>
	<sequence>
		<invoke name="2"/>
		<flow>
			<!-- upper flow of concurrency -->
			<sequence>
				<invoke name="11"/>
				<invoke name="13"/>
			</sequence>
			<!-- lower flow of concurrency -->
			<sequence>
				<invoke name="21"/>
			</sequence>
		</flow>
		<invoke name="3"/>
	</sequence>
</process>