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Re: AW: [jwt-dev] Re: STP IM and JWT metamodel

Hi Fabrice,

Thanks for your interest in the work around STP-IM. I will let Andrea respond about the monitoring part of Spagic. Regarding your question on STP-IM, could you elaborate a bit with maybe an example what you mean here by platform specific and platform independent model? I understand the terminology as defined in MDA but I'd like to better grasp your meaning of these terms in the context of the STP-IM, which is itself a platform independent metamodel. If by "platform specific" you mean the content of the properties containing data about things such as JBI and BPEL, do you mean to make a stronger separation of such properties from the rest of the model? If this is what you mean, could you perhaps make a suggestion of how you'd see this realised?

Cheers,
Adrian.

On Jan 4, 2008, at 11:14 AM, Fabrice Dewasmes wrote:

Hi all,

I've had the opportunity to assist to a presentation of Spagic and I must admit I was very interested by what it covers. I think that it could be the missing link between everything when you want to have in a top-down SOA approach and already have chosen what will be your backend (JBI, Mule, ...). It seems to me that the STP-IM is a nice idea and should be able to support very different use cases with quite some work.

It's great news that both projects are OK to collaborate. The switch from STP-IM to JWT meta-model and vice versa should be sufficient for a first step. But for me both projects should work more closely. What I find interesting for spagic could be the WAM part of JWT. As a matter of fact, Spagic already supports some kind of deployment and monitoring but most of it is done through their web application. Could be interesting to be able to :
* deploy and debug step by step the processes
* do the monitoring using a tool like Eclipse. And for this part, it may be interesting to have the WAM part usable as a RCP application.

For STP-IM, I haven't looked at how the model is done but don't you think it could be interesting to have the platform specific parts of the model represented as marks so that those platform specific things end up in something like an independant layer that could be applied or not on the Platform independant model ?

Fabrice
On Jan 3, 2008 7:15 PM, Marc Dutoo <marc.dutoo@xxxxxxxxxxx> wrote:
Hi Adrian, Florian

What a highly interesting succession of emails !
I'm all the more sorry I couldn't participate to it (my holidays would
have hold this against me)
Anyway, thanks for all who did ;)

Nevertheless, it clarifies major elements concerning STP-IM and its
interactions with JWT, and I personally very much agree with everything
that has been said here.

To sum it up, STP-IM properties play the same role as EAnnotations in
STP BPMN Ed.'s format, i.e. they are to be used to provide whatever
source format specific information might be useful in a given
transformation to another target format. This implies they are specific
not only to the source or target format, but to the very transformation
algorithm that is used to transform the one into the other, meaning that
"at worst" there is a risk of "noodle plate" or exponential property
definitions.

I believe reducing and managing this problem is of the highest
importance in JWT and in STP-IM as well, as Adrian proposed in his last
paragraph : "It might be a good idea to properly document and classify
the  properties that are used in different transformations. This way,
people can easily use them when adding other transformations...". I
think the answer is a combination of proper guidelines (ex. property
naming guidelines) for writing transformations, overall methodology
(project organisation, documentation) and why not a bit of architecture
to ease and unify a source or target format's most recognized and
"mainstream" properties.


Here is what I've thought about for JWT in order to tackle this problem
(it may obviously be useful for STP-IM) :

on the side of methodology and tests :
  * definition of a set of meaningful (especially important because of
the "Business" part in BPM ) samples that cover as much BPM features
(XOR, subprocesses...) as possible. Possibly, definition of "unit
samples", but those would be harder to delineate at a truly "unitary" level.
  * one dev subproject per transformation, each with its own
algorithms, and its own version of all default samples, and more if
required.
  * a single common jwt-samples subproject, where are gathered and
consistently merged samples from as many as possible transformations.
The idea is to have ex. a single set of BPMN samples, a single set of
XPDL samples, a single set of JWT samples, a single set of BPEL samples,
and that all transformations (ex. BPMN2JWT, JWT2XPDL, JWT2BPMN...
including reverse ones) work using the same samples.
  * source or target format specific guidelines, along with the list of
"officially recognized" properties for this format. Those are enriched
by transformation implementors who have a working transformation which
doesn't break the existing list and common jwt-samples or / and in
agreement with implementors of already existing transformations using
"officially recognized" properties.
  * common guidelines to transforming to and from the JWT model,
including default advised property / annotation/ ... naming. Those are
enriched by format specific guidelines contributors, with the assent of
the others. NB. there is no "officially recognized" properties at this
level, since it should be the JWT model.

Obviously, those last two should be made available as public and up to
date as possible (wiki, web site...).


on the side of architecture :
  * extended JWT model using ex. STP BPMN-like EAnnotations or STP
IM-like properties
  * using ATL for transformations (as for now)

I'm also thinking of a mechanism of templating transformations
  * to ease their development, including testing against "official" samples
  * to ease and unify the use of "officially recognized" properties for
each source and target format (without forbidding to add others)


I really believe the key to long term success is to at the same time
keep a strong consistency within a growing set of core transformations,
and ease the development of new transformations as well as their
contributions of new "officially recognized" properties.

Any feedback welcome !

Regards
Marc


Adrian Mos wrote:

> Hi Florian,
>
> You are right in thinking that the intermediate model is not just
> used  for one transformation between BPMN and ServiceMix in two steps.
> It is  a generic means of moving information between different editors
> and  platforms and currently we have the support for transformations
> between BPMN, BPEL and ServiceMix.
>
> The question you are raising about the generality of property
> definitions is a good one. Basically you are asking how if the model
> is generic, can you define things that all downstream transformations
> can understand. The simple answer is, somebody must put them there
> with the shared understanding of the needs of the target. The IM
> ALLOWS the definition of properties with specific semantics but does
> not specify the semantics of each set of properties. This is the
> price  for generality, you can't have a model that is both generic
> and  specific at the same time, and we didn't want to provide the
> union of  all the elements of the supported metamodels in the IM.
>
> So, somehow, the information about how to map concepts from BPMN to
> JBI (for example) must be put in the IM. And here is the choice we
> made: the concepts that are general enough to be useful in a variety
> of situations (such as binding, or step, or service) are directly
> represented as elements in the IM. The other concepts, specific to
> one  technology or editor, are injected using the properties. As you
> have  rightly noticed, from the BPMN editor we already populate the
> properties needed to go from BPMN to JBI or BPEL. This is a choice
> that allows very good integration of editors using standard extension
> points of BPMN and the IM. Since all the information for JBI can be
> put in the properties directly from the BPMN editor, we are able to
> directly generate JBI. However for BPEL, some information must still
> be added using the BPEL editor, which is why this editor must be
> opened and used before being able to completely generate the
> executable BPEL (Andrea correct me if I'm wrong here).
>
> So you already see two approaches for putting non-standard (i.e. non
> generic enough) information in the IM, needed for particular
> transformations. One is by directly defining the properties from the
> source editor, the other by adding specific information in the target
> editor. You can also imagine using an intermediate editor for example
> when generating SCA deployable artefacts. You can use BPMN to
> describe  a process, open the SCA editor to add and modify SCA
> specific  information and finally generate the running SCA artefacts.
> So, while  the IM allows the definition of properties that can have
> different  semantics under different contexts, it only standardises
> some  elements, the ones deemed generic enough (and this is of course
> work  in progress as we'll keep improving this generic set to
> correspond to  the needs of STP). Again, the semantics of the
> properties is in the  hands of the transformation developers, the ones
> that specify how to  move to and from the IM and different editors.
>
> It might be a good idea to properly document and classify the
> properties that are used in different transformations. This way,
> people can easily use them when adding other transformations that can
> result in artefacts generated for editors already having
> transformations (to or from the IM). This and especially the
> description of the way to add transformations to/from the IM are
> important for the understanding and adoption of the IM and will be
> done as soon as possible.
>
> Hope this clarifies things a bit...
>
> Happy New Year! :)
> Adrian.
>
> On Dec 28, 2007, at 10:29 AM, Florian Lautenbacher wrote:
>
>> Hi Adrian, hi Andrea,
>>
>> thanks a lot for the clarification about the STP IM. Yes, we are also
>> looking forward to work with you. Currently we have some efforts on
>> transformations between BPMN and JWT resp. XPDL and JWT, but after
>> that is
>> finished we are looking forward to work on a mapping STP IM <-> JWT.
>>
>> One last question: you say that STP IM is a transporter model (or  Pivot
>> model as I understand it), so I only need transformations from say
>> BPMN to
>> STP IM and from there to e.g. ServiceMix Assembly. But how do I know
>> that my
>> first transformation from BPMN to STP IM needs to write specific
>> properties
>> such as "interface", "method call" or "participant" that ALL upcoming
>> transformations (to ServiceMix, to BPEL, to XPDL, to whatever)
>> understand
>> where to look for? Adrian said that STP IM could be described as an
>> "intersection" between other relevant standards.. And that's really
>> good! But
>> then there needs to be a mechanism or naming convention for the
>> generated
>> and added properties, every transformation should take care of and
>> stick to
>> in order to have several model transformations (from BPMN to STP IM,
>> from
>> JWT to STP IM, from STP IM to BPEL, from STP IM to SCA, etc.)
>> working after
>> each other, am I right?
>>
>> Or is the "transporter model" thought of as a model simply used in
>> *one*
>> transformation from BPMN to ServiceMix, but this transformation has  two
>> steps inside!? But what would be the use of such a transporter
>> model? So I
>> don't think its like that.
>>
>> Thanks for this last answer and a happy new year 2008 to all of you!
>>
>> Best regards,
>>
>> Florian
>>
>> -----Ursprüngliche Nachricht-----
>> Von: jwt-dev-bounces@xxxxxxxxxxx [mailto:jwt-dev-
>> bounces@xxxxxxxxxxx] Im
>> Auftrag von Adrian Mos
>> Gesendet: Samstag, 22. Dezember 2007 12:53
>> An: Florian Lautenbacher; Andrea Zoppello
>> Cc: Oisin Hurley; Java Workflow Toolbox; Adrian Skehill
>> Betreff: [jwt-dev] Re: STP IM and JWT metamodel
>>
>> Hi Florian,
>>
>> Andrea gave you the detailed answers for your questions, so I just
>> want to
>> say that if you're looking for help with transformations you can
>> definitely
>> count on us. So if you have any questions about transforming
>> elements from
>> JWT to STP-IM or the other way around, feel free to fire them up on
>> the STP
>> mailing list, you'll get an answer quickly.
>>
>> Also, to follow up on what Andrea said and what I noted previously,  the
>> STP-IM is a generic "transporter" model, intended to bridge the
>> variety of
>> SOA editors in STP. So, the semantics of properties to different
>> elements
>> can differ based on the transformation that is going to use them.
>> The idea
>> is that we do not try to offer all the semantics in the IM, rather
>> just the
>> means to attach it, so that we can keep a high level of generality
>> while
>> still preserving the most important SOA concepts as top-level.
>>
>> Looking forward to working with you guys, Best wishes, Adrian.
>>
>> On Dec 21, 2007, at 11:36 AM, Andrea Zoppello wrote:
>>
>>> Hi,
>>>
>>> See the comments inline.
>>>
>>> Florian Lautenbacher ha scritto:
>>>
>>>> Hi Adrian, hi Andrea,
>>>>
>>>> thanks for your helpful clarification about the metamodel of STP IM.
>>>> I now had a closer look at the metamodel in your SVN and it is (in  my
>>>> opinion)
>>>> much better designed than the one that is shown on your web site.
>>>> In fact
>>>> the core concepts are very similar to the core metamodel of JWT
>>>> (which can be found on [1]). In STP IM you got a Process which
>>>> contains * Steps and * Transitions. Each step has a name, a
>>>> description, a number of sourceTransitions and targetTransitions as
>>>> well as several observableAttributes. You also got ControlServices
>>>> with subclasses like SplitControl or JoinControl. There can be  normal
>>>> Transitions or TransitionsUnderCondition. And (nearly?) everything  is
>>>> a configurable
>>>>
>>>
>>>> element.
>>>>
>>>> Now looking at the JWT metamodel it is very much alike: here
>>>> everything is a ModelElement. There are ActivityNodes which are
>>>> connected via ActivityEdges (using source, target, in and out with
>>>> same cardinality as sourceTransitions, targetTransitions etc. in STP
>>>> IM). There can be several types of ActivityNodes: one would be an
>>>> Action (probably a Step in
>>>> IM) or it
>>>> could be a ControlNode such as a ForkNode or a JoinNode. An
>>>> ActivityEdge might have a Guard (making it a
>>>> "TransitionUnderCondition") whereas the Guard is specified in a
>>>> GuardSpecification (with only a proprietary notation allowed).
>>>>
>>>> Regarding your description of Properties and ObservableAttributes I
>>>> guess that data that is necessary for execution (which might have
>>>> been added to BPMN and shall be transformed into BPEL e.g.) is added
>>>> as a property to the relevant step, am I right?
>>>>
>>> Yes.
>>>
>>> For example for a Step that is configured with  Service  [StartService]
>>> ServiceBinding [HTTP-InputBindingComponent] the properties will be
>>> driven by the HTTP-InputBindingComponet, So the step will have
>>> properties like:
>>>
>>> URL:
>>> isSoap:
>>> and so on.
>>>
>>>
>>> Quite different is the concept of relevant data:
>>>
>>> Relevant data are extracted when the process is executed, evluating
>>> _expression_ on messages ( exchanged by endpoint in the case of Jbi )  or
>>> variable in the case of ( BPEL).
>>>
>>> An example of relevant data is customerID extracted by /RECORD/
>>> @customerId
>>>
>>> Thanks for clarification about the owner attribute. Yes, I was more
>>> thinking
>>>
>>>> about a participant or role than about an owner. Is this data ( e.g.
>>>> which is
>>>> available in a swimlane or pool in BPMN) then added as a property
>>>> right now to each Step?
>>>>
>>> As i say in previous post we'e not yet provided in the stp
>>> intermediate model the concept of participiant role.
>>> BTW i think that we could support this in BPMN editor in two ways:
>>>
>>> 1) Using the lane ( ant this will add some additional property on the
>>> step, or better it will configure a particular
>>>  RolebAssignedStep, HumanTaskStep )
>>> 2) Get a view with a participiant list that we could drag anbd drop  on
>>> the activities
>>>
>>> We cannot use the BPMN pool concept beacuse a pool in the im is  mapped
>>> in to a process.
>>>
>>>> I agree with Adrian and Marc that a first step would be having a
>>>> transformation from JWT to STP IM (and the other way round).
>>>> However, since
>>>> the metamodels are quite similar, this should not be so hard. Here  at
>>>> JWT we need to discuss who will be responsible for this task. Maybe
>>>> somebody of STP might be able to assist us here!?
>>>>
>>> You're welcome. Ask what you want???
>>>
>>>> I am still wondering how you are planning to include the information
>>>> from one metamodel in a way that it is clear in a next  transformation
>>>> step where it should go. So, if I specify the owner of a step in a
>>>> pool or lane in BPMN, how is this information kept in STP IM so I  can
>>>> work with that when generating e.g. BPEL or XPDL-code? I guess you
>>>> need some predefined values as properties that both model
>>>> transformations use!? Or will there be a query language (such as RQL
>>>> or SPARQL) where you can find the "semantics" of the property?
>>>> Best regards and looking forward to some more fruitful discussions,
>>>>
>>>> Florian
>>>>
>>>>
>>> Intermediate Model is a very generic model so you could have
>>> situations where some properties ( for example of the step ) will be
>>> important by  code generator A and others will be  need  by code
>>> generator B.
>>>
>>> The concept is that IM bring you the information in a very generic
>>> way, than  is responsibility of specific code generator to transform
>>> that information in something executable.
>>>
>>> To bring you an example, now i'm working in generating servicemix
>>> service assembly applications from intermediate model, and it's my
>>> codegenerator plugins that knows ( for example how to organize  service
>>> units, how to make cfg files and so on .... ).
>>>
>>> I don't know if it's clear, if you've some doubt please write me.
>>>
>>> Regards
>>> Andrea
>>>
>>>> [1]
>>>> http://wiki.eclipse.org/images/2/2f/AgilPro_MetamodelDescription.pdf
>>>>
>>>> -----Ursprüngliche Nachricht-----
>>>> Von: Andrea Zoppello [mailto:andrea.zoppello@xxxxxx] Gesendet:
>>>> Montag, 17. Dezember 2007 10:15
>>>> An: Florian Lautenbacher
>>>> Cc: Adrian Skehill; Adrian Mos
>>>> Betreff: Re: Current state of STP IM?
>>>>
>>>> Hi,
>>>>
>>>> Sorry for the late response but i'm just come back from Javapolis.
>>>>
>>>> See comments inline
>>>> Adrian Skehill ha scritto:
>>>>
>>>>> Florian Lautenbacher wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I am wondering what the current state of the STP Intermediate  model
>>>>>> is? Is the version on the Wiki [1] up to date?
>>>>>>
>>>> I think version on the wiki is not updated. The version that we're
>>>> going to commit will be the really the first version.
>>>>
>>>>
>>>>>> If so, I am curious why a step is part of a process, but the
>>>>>> transition is not?
>>>>>> And, on the other hand, why there is only one edge between a step
>>>>>> and a transition with cardinality *. In many other standards (like
>>>>>> UML activity diagrams) there are always two edges between a node
>>>>>> (=ActivityNode in UML) and a transition (=ActivityEdge in
>>>>>> UML) specifying that a transition has exactly two ends  (cardinality
>>>>>> of 1 at each edge)?
>>>>>>
>>>>
>>>> In the version that we're going to commit a process will have a set
>>>> of steps and a set of transitions. A transition wil have a source
>>>> step and a target step then in the  A step there will be  two  inverse
>>>> relations a relation called sourceTransitions 1.* ( all transition
>>>> for which the step is a source step ) and a realtion called
>>>> targetTransition ( all transition for whcih the step is target )
>>>>
>>>>
>>>>>> How are the conditions at TransitionUnderCondition specified? Are
>>>>>> these boolean conditions connected with AND, OR, XOR and NOT? Or  is
>>>>>> this open to each implementation (BPMN, SCA, JBI, etc.)?
>>>>>>
>>>>
>>>> The transition under condition will have a "Condition" ( Condition
>>>> abstract entity ) where a condition could be an  "ExpressionCondition"
>>>> ( a condition expressed in some language Xpath, groovy, or a
>>>> condition on header properties "PropertyCondition".
>>>>
>>>>>> Do only Transitions have ObservableAttributes? How about  attributes
>>>>>> that are specified at a step?
>>>>>>
>>>> In the actual version of the Intermediate Model we've introduced the
>>>> relation between Observable Attribute and Step ( 1..*  each step
>>>> could have one or more observable attribute ).
>>>>
>>>> By the way what's important is to clarify the difference between
>>>> "ObservableAttribute" and "Property" of a Step.
>>>>
>>>> Properties are information needed to configure the step in a
>>>> particular runtime,and the properties set depends by ServiceBinding.
>>>> Observable attribute are data that will be extracted when the  process
>>>> will be executed to be visualuzed and monitored, by monitoring  tools.
>>>>
>>>>
>>>>>> Does a process or a step has no owner, but only a service?
>>>>>>
>>>>
>>>> A process is a subclass  of service so process could have owner.
>>>> What's important is to make distinct the concept of  "Owner" from  the
>>>> concept of  "Participiant/Actor/Role" as we mean when we talk about
>>>> workflow and in general process that require "human task".
>>>>
>>>> At the moment we've not in the model the concept of "Particpiant/
>>>> Actor/Role"
>>>> for the support of worflow concept, but in the future we're going to
>>>> introduce something about.
>>>>
>>>> Basically ( it's just an idea that we need to discuss with other
>>>> members
>>>> ) we'll introduce the concept of role, and a subclass of Step entity
>>>> ( let me say RoleAssignedStep or  HumanTaskStep ) where we model the
>>>> relation beteween a step and a role.
>>>>
>>>> For "Owner" instead we mean the provider of a service ( process ) as
>>>> it is in service registry ( UDDI ) world.
>>>> But this part is not complete yet.
>>>>
>>>>>> Looking forward to your answers,
>>>>>>
>>>>>>
>>>>
>>>> Feel free to contact me if you need other information.
>>>>
>>>>>> Florian Lautenbacher
>>>>>> -JWT project lead-
>>>>>>
>>>>>>
>>>>>> [1] http://wiki.eclipse.org/STP_Internal_Model_Discussion
>>>>>>
>>>>> Hi Florian,
>>>>>
>>>>
>>>> Hi
>>>> Andrea Zoppello
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>>
>>> *Andrea Zoppello*
>>> ___________________________________________
>>> <www.spagoworld.org>
>>>
>>> Spagic Architect
>>> ___________________________________________
>>>
>>> Architect
>>> Research & Innovation Division
>>> *Engineering Ingegneria Informatica S.p.A.
>>> *
>>> Corso Stati Uniti, 23/C - 35127 Padova - Italy
>>> Phone:  +39-049.8692511    Fax:+39-049.8692566
>>>
>>> *www.eng.it                    www.spagoworld.org*
>>>
>>>
>>>
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