Home » Archived » M2M (model-to-model transformation) » [ATL] how to find an already generated element in non-declarative rules ?
| [ATL] how to find an already generated element in non-declarative rules ? [message #37805] |
Tue, 15 May 2007 08:46  |
Eclipse User |
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Originally posted by: sylvain.maillard.univ-nantes.fr
Hi All,
I'm stuck with a simple (?) problem: I want to transform a model (MA)
that conforms to a home-made metamodel (MMA) into another model that
conforms to eCore.
In my MMA, I have an element that can be combined with itself (i.e.
Element has a collection of <Element> called 'elements').
I want to transform these elements into EClass, so I have a declarative
rule that takes a Element in its 'from' clause and produce a EClass in
its 'to' clause.
But now I want the collection 'elements' to become a EReference in the
target model.
Because there is no corresponding entity in my source model, I can not
create a declarative rule for this transformation.
So I have added a called rule that create the new EReference, but I
can't see how to find the target of my EReference, which must be an
already generated EClass...
I understand that ATL can find target elements from the input elements,
but I think this can work only for declarative rules ??
Please Help !
Thanks in advance,
Sylvain
--
Sylvain
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| Re: [ATL] how to find an already generated element in non-declarative rules ? [message #37935 is a reply to message #37805] |
Tue, 15 May 2007 13:58  |
| Eclipse User |
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Originally posted by: sylvain.maillard.univ-nantes.fr
Ok forget it,
In my called rule that create EReference, I'have added a parameter that
is the eType of eReference. As the rule is called from a declarative
rule, ATL is able to find the correct target element.
> Hi All,
>
> I'm stuck with a simple (?) problem: I want to transform a model (MA) that
> conforms to a home-made metamodel (MMA) into another model that conforms to
> eCore.
> In my MMA, I have an element that can be combined with itself (i.e. Element
> has a collection of <Element> called 'elements').
> I want to transform these elements into EClass, so I have a declarative rule
> that takes a Element in its 'from' clause and produce a EClass in its 'to'
> clause.
> But now I want the collection 'elements' to become a EReference in the target
> model.
> Because there is no corresponding entity in my source model, I can not create
> a declarative rule for this transformation.
> So I have added a called rule that create the new EReference, but I can't see
> how to find the target of my EReference, which must be an already generated
> EClass...
> I understand that ATL can find target elements from the input elements, but I
> think this can work only for declarative rules ??
>
> Please Help !
>
> Thanks in advance,
> Sylvain
--
Sylvain
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| Re: [ATL] how to find an already generated element in non-declarative rules ? [message #37969 is a reply to message #37805] |
Tue, 15 May 2007 14:00 |
| Eclipse User |
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Originally posted by: rchevrel.sodius.com
This is a multi-part message in MIME format.
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Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Content-Transfer-Encoding: 8bit
Hi Sylvain,
I cannot completely understand your problem but I think this code could
help you.
-------------------------------------------------
rule root {
from
in_elm1 : MMa!Element
to
out_elm1 : ECore!EClass ()
}
-------------------------------------------------
rule elements {
from
-- you match a relation
e1 : MMa!Element,
e2 : MMA!Element (
e1.elements->includes(e2)
)
to
out_elm1 : ECore!EReference (
-- you attach this element with its parent
eContainer <- e1
),
out_elm2 : ECore!EReference (
-- you attach this element with its parent
eContainer <- e2,
-- you set the opposite
eOpposite <- out_elm1
)
}
-------------------------------------------------
You could also use a lazy rule.
Please send a concrete example if you have some problems.
*R
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| Re: [ATL] how to find an already generated element in non-declarative rules ? [message #37999 is a reply to message #37969] |
Tue, 15 May 2007 14:17 |
| Eclipse User |
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Originally posted by: sylvain.maillard.univ-nantes.fr
Hi Regis,
With your code I think I can remove the called rule ! I did not see
this tips to match the relation.
thanks
Sylvain
> Hi Sylvain,
>
> I cannot completely understand your problem but I think this code could help
> you.
>
> -------------------------------------------------
> rule root {
> from
> in_elm1 : MMa!Element
> to
> out_elm1 : ECore!EClass ()
> }
> -------------------------------------------------
> rule elements {
> from
> -- you match a relation
> e1 : MMa!Element,
> e2 : MMA!Element (
> e1.elements->includes(e2)
> )
> to
> out_elm1 : ECore!EReference (
> -- you attach this element with its parent
> eContainer <- e1
> ),
> out_elm2 : ECore!EReference (
> -- you attach this element with its parent
> eContainer <- e2,
> -- you set the opposite
> eOpposite <- out_elm1
> )
> }
> -------------------------------------------------
>
> You could also use a lazy rule.
>
> Please send a concrete example if you have some problems.
>
> *Régis CHEVREL* <mailto:rchevrel@sodius.com>
>
>
> SODIUS*
> *6, rue Cornouaille
> 44319 Nantes - France
>
> Phone: +33 (0)2 28 23 54 34
>
> ***www.mdworkbench.com* <http://www.mdworkbench.com/>* *
> Draw more value from your model
--
Sylvain
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| Re: [ATL] how to find an already generated element in non-declarative rules ? [message #38059 is a reply to message #37969] |
Tue, 15 May 2007 15:48 |
| Eclipse User |
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Originally posted by: sylvain.maillard.univ-nantes.fr
Hi Régis
> Hi Sylvain,
>
> I cannot completely understand your problem but I think this code could help
> you.
>
> -------------------------------------------------
> rule root {
> from
> in_elm1 : MMa!Element
> to
> out_elm1 : ECore!EClass ()
> }
> -------------------------------------------------
> rule elements {
> from
> -- you match a relation
> e1 : MMa!Element,
> e2 : MMA!Element (
> e1.elements->includes(e2)
> )
> to
> out_elm1 : ECore!EReference (
> -- you attach this element with its parent
> eContainer <- e1
Unfortunately this doesn't work as eContainingClass from MOF is not
modifiable. It seems that a newly created EReference cannot be attached
to another EClassifier like that. I must explicitly add it to
eStructuralFeatures features of the EClass :-(
> ),
> out_elm2 : ECore!EReference (
> -- you attach this element with its parent
> eContainer <- e2,
> -- you set the opposite
> eOpposite <- out_elm1
> )
> }
> -------------------------------------------------
>
> You could also use a lazy rule.
>
> Please send a concrete example if you have some problems.
>
> *Régis CHEVREL* <mailto:rchevrel@sodius.com>
>
>
> SODIUS*
> *6, rue Cornouaille
> 44319 Nantes - France
>
> Phone: +33 (0)2 28 23 54 34
>
> ***www.mdworkbench.com* <http://www.mdworkbench.com/>* *
> Draw more value from your model
--
Sylvain
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| Re: [ATL] how to find an already generated element in non-declarative rules ? [message #38157 is a reply to message #38125] |
Tue, 15 May 2007 16:30 |
| Eclipse User |
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Originally posted by: sylvain.maillard.univ-nantes.fr
Hi again,
> Hello Sylvain,
>
> >> rule elements {
> >> from
> >> -- you match a relation
> >> e1 : MMa!Element,
> >> e2 : MMA!Element (
> >> e1.elements->includes(e2)
> >> )
> >> to
> >> out_elm1 : ECore!EReference (
> >> -- you attach this element with its parent
> >> eContainer <- e1
> >
> > Unfortunately this doesn't work as eContainingClass from MOF is not
> > modifiable. It seems that a newly created EReference cannot be attached
> > to another EClassifier like that. I must explicitly add it to
> > eStructuralFeatures features of the EClass :-(
>
> Being able to navigate and set references in both directions is *very* useful
> in model transformation, especially when using a declarative style.
>
> Here is an excerpt of a slide on metamodeling hints that I give to students:
>
> * Define bidirectional associations (i.e., pairs of references)
> => Makes the model easier to navigate and populate
>
>
> It seems that Ecore was not designed by model transformation developers :-).
>
I agree with you on that point ;-)
>
> A quick and dirty (i.e., imperative) way to solve your problem would be to
> add an action block to rule "elements" to perform the setting in the opposite
> direction:
>
> do {
> e1.eStructuralFeatures <- out_elm1;
> }
well, I dont understand that: e1 refers to my input model, so it
doesn't have the eStructuralFeatures ! In order to do this I must get
the generated target eClass and I think it's bad ;-)
do
{
giveMeTheGeneratedEClassFor(e1).eStructuralFeatures <- out_elm1;
}
should solve my problem ;-)
>
>
> Best regards,
>
> Frédéric Jouault
--
Sylvain
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| Re: [ATL] how to find an already generated element in non-declarative rules ? [message #38324 is a reply to message #38258] |
Tue, 15 May 2007 17:10 |
| Eclipse User |
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Originally posted by: sylvain.maillard.univ-nantes.fr
> Hello again,
>
> >> A quick and dirty (i.e., imperative) way to solve your problem would
> >> be to add an action block to rule "elements" to perform the setting in
> >> the opposite direction:
> >>
> >> do {
> >> e1.eStructuralFeatures <- out_elm1;
> >> }
> >
> > well, I dont understand that: e1 refers to my input model, so it doesn't
> > have the eStructuralFeatures ! In order to do this I must get the
> > generated target eClass and I think it's bad ;-)
> >
> > do
> > {
> > giveMeTheGeneratedEClassFor(e1).eStructuralFeatures <- out_elm1;
> > }
> >
> > should solve my problem ;-)
>
> Of course, you are right. I so much focused on the reverse setting part of
> the issue that I missed this ;-).
>
> giveMeTheGenerated<something>For is called resolveTemp in ATL.
>
> This case is one of the rare cases when we are going to actually use
> resolveTemp to resolve to the default target element (because we are doing it
> in an imperative block):
>
> do {
> thisModule.resolveTemp(e1, 'out_elm1').eStructuralFeatures <- out_elm1;
> }
Well I tried this and I get an EmptyStackException... I dont understand
why: every elements should have been created at this time ?
>
>
>
> Best regards,
>
> Frédéric Jouault
--
Sylvain
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| Re: [ATL] how to find an already generated element in non-declarative rules ? [message #38422 is a reply to message #38324] |
Tue, 15 May 2007 17:21 |
| Eclipse User |
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Originally posted by: sylvain.maillard.univ-nantes.fr
>> Hello again,
>>
>> >> A quick and dirty (i.e., imperative) way to solve your problem would
>> >> be to add an action block to rule "elements" to perform the setting in
>> >> the opposite direction:
>> >>
>> >> do {
>> >> e1.eStructuralFeatures <- out_elm1;
>> >> }
>> >
>> > well, I dont understand that: e1 refers to my input model, so it doesn't
>> > have the eStructuralFeatures ! In order to do this I must get the
>> > generated target eClass and I think it's bad ;-)
>> >
>> > do
>> > {
>> > giveMeTheGeneratedEClassFor(e1).eStructuralFeatures <- out_elm1;
>> > }
>> >
>> > should solve my problem ;-)
>>
>> Of course, you are right. I so much focused on the reverse setting part of
>> the issue that I missed this ;-).
>>
>> giveMeTheGenerated<something>For is called resolveTemp in ATL.
>>
>> This case is one of the rare cases when we are going to actually use
>> resolveTemp to resolve to the default target element (because we are doing
>> it in an imperative block):
>>
>> do {
>> thisModule.resolveTemp(e1, 'out_elm1').eStructuralFeatures <- out_elm1;
>> }
>
> Well I tried this and I get an EmptyStackException... I dont understand why:
> every elements should have been created at this time ?
OK my mistake: the second parameter of resolveTemp should be set to the
same name as the one specified in the rule used to create the parent
element ! in my case it was 'class' rather than 'out_elm1'.
Thanks for your help Frédéric ;-)
>
>>
>>
>>
>> Best regards,
>>
>> Frédéric Jouault
--
Sylvain
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