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QVT to attach elements as children to a root element [message #1724357]

Tue, 23 February 2016 10:58

Michael Zach

Messages: 7
Registered: November 2015

Junior Member

Hello,

for MDA I have been using QVT and XPAND.

But as it seems to me, XPAND is always needing a root element in the model to start from. And I have not been able so far to write a QVT script which creates such a root element and then attaches all other elements transformed from the source (PIM) model in such a way, that they are attached as children to the root element (e.g. representing the model itself).

How are you doing this?

Kind regards
Michael

have been following these tutorials so far:
http://www.vogella.com/tutorials/EclipseEMF/article.html
http://redpanda.nl/index.php?p=tutorial9
http://www.peterfriese.de/getting-started-with-code-generation-with-xpand/

[Updated on: Tue, 23 February 2016 11:07]

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Re: QVT to attach elements as children to a root element [message #1724368 is a reply to message #1724357]

Tue, 23 February 2016 11:41

Ed Willink

Messages: 7267
Registered: July 2009

Senior Member

Hi

If you want a root element then you must model it, perhaps with a Root
metamodel element that can contain all sorts of Element from which all
other classes derive.

cf UML where a Model is typically the root and everything else is an
Element.

The above is true for all modeling tools. I'm not familiar with Xpand
but it may be closer to a Java/XML tool and so may reify the document
(EMF Resource) as a root object whose contents are Resource.contents.

Regards

Ed Willink

On 23/02/2016 10:58, Michael Zach wrote:
> Hello,
>
> for MDA I have been using QVT and XPAND.
> But as it seems to me, XPAND is always needing a root element in the
> model to start from. And I have not been able so far to write a QVT
> script which creates such a root element and then attaches all other
> elements transformed from the source (PIM) model in such a way, that
> they are attached as children to the root element (e.g. representing
> the model itself).
>
> How are you doing this?
>
> Kind regards
> Michael
>
>

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Re: QVT to attach elements as children to a root element [message #1725213 is a reply to message #1724368]

Tue, 01 March 2016 18:13

Michael Zach

Messages: 7
Registered: November 2015

Junior Member

Hi Ed,

> If you want a root element then you must model it.

Yes of course.

But I want to (in an MDA like approach) define a platform-independent model (PIM) and then use QVT to transform this into a platform-specific model (PSM).

First I create a new empty root element in the PSM, copy all properties for it over from the root in the PIM (possibly transform the values ...). Thats OK.

But then the point is, I can not find a way in QVT how to create other new elements in the PSM which I can then attach as sub-elements to the root-element. They all end up as root elements.

Does anyone have some example code in QVT where I can see if/how this is possible?

Thanks,
Michael

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Re: QVT to attach elements as children to a root element [message #1725215 is a reply to message #1725213]

Tue, 01 March 2016 18:52

Ed Willink

Messages: 7267
Registered: July 2009

Senior Member

Hi

The distributed UML2RDBMS example creates hierarchy.

Generally if you want something to have a non-null container you need to
assign that non-null container, either by setting a modeled container,
or more commonly by assigning a set of contained children.

Regards

Ed Willink

On 01/03/2016 18:13, Michael Zach wrote:
> Hi Ed,
>
>> If you want a root element then you must model it.
>
> Yes of course.
>
> But I want to (in an MDA like approach) define a platform-independent
> model (PIM) and then use QVT to transform this into a
> platform-specific model (PSM).
>
> First I create a new empty root element in the PSM, copy all
> properties for it over from the root in the PIM (possibly transform
> the values ...). Thats OK.
>
> But then the point is, I can not find a way in QVT how to create other
> new elements in the PSM which I can then attach as sub-elements to the
> root-element. They all end up as root elements.
>
> Does anyone have some example code in QVT where I can see if/how this
> is possible?
>
> Thanks,
> Michael

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