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Difference between References [message #722609]

Tue, 06 September 2011 10:32

Daniel Trierweiler

Messages: 67
Registered: June 2011

Member

Hello guys,

I'm wondering what the internal difference between EReferences generated by Xtext is.
Basically I need to know whether my reference is from this type "system = System" or from this type "variantName = [Variant | QualifiedName]". Both appear in the debugger as EReferenceImpl and I can't spot a difference between them.

Does anyone have an idea related to this?
Thanks a lot Smile

Daniel

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Re: Difference between References [message #722612 is a reply to message #722609]

Tue, 06 September 2011 10:36

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

the difference is "containment". cross-references not contained.

~Christian

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Difference between References [message #722620 is a reply to message #722612]

Tue, 06 September 2011 10:56

Daniel Trierweiler

Messages: 67
Registered: June 2011

Member

Alright.
But how can I access this in my code? I can't find anything related to containment in the debugger.

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Re: Difference between References [message #722622 is a reply to message #722620]

Tue, 06 September 2011 11:03

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

why in the debugger? its static information (see ecore)

in the debugger you see the referenced element not the reference itself.
you can of course get a hint that the econtainer of the child element in the tree is the same as the parent element in the tree.

~Christian

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Difference between References [message #722628 is a reply to message #722622]

Tue, 06 September 2011 11:11

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

As an addition,
you may evaluate an expression like ((EReference)context.eContainingFeature()).isContainment()
to find out if it is contained from the debugger as well

~Christian

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Difference between References [message #722634 is a reply to message #722622]

Tue, 06 September 2011 11:34

Daniel Trierweiler

Messages: 67
Registered: June 2011

Member

Well I need to know those things during runtime.

I solved it with your help this way:

if(eObj.eClass() == ((EObject)obj).eContainer().eClass())
	//containment ref
else
	//other ref

(eObj being the parent eobject, obj being the referenced eobject)

Thanks a lot Christian, as usual Smile

[Updated on: Tue, 06 September 2011 11:35]

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Re: Difference between References [message #722635 is a reply to message #722634]

Tue, 06 September 2011 11:35

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

this won't work: use ((EReference)context.eContainingFeature()).isContainment()

~Christian

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Difference between References [message #722637 is a reply to message #722609]

Tue, 06 September 2011 11:34

Henrik Lindberg

Messages: 2509
Registered: July 2009

Senior Member

There are plenty of e-prefixed-methods on EMF based objects that give
you access to meta data and allow you to navigate the model.

While debugging I often use the JDisplay view and do things like:

// where is x contained?
x.eContainer();

// what is x to it's container?
x.eContainingFeature()

etc.

Hope that helps.
- henrik

On 9/6/11 12:32 PM, Daniel Trierweiler wrote:
> Hello guys,
>
> I'm wondering what the internal difference between EReferences generated
> by Xtext is.
> Basically I need to know whether my reference is from this type "system
> = System" or from this type "variantName = [Variant | QualifiedName]".
> Both appear in the debugger as EReferenceImpl and I can't spot a
> difference between them.
>
> Does anyone have an idea related to this?
> Thanks a lot :)
>
> Daniel

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