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Accessing attributes in different resources [message #1553045]

Thu, 08 January 2015 13:16

Andreas Flügge

Messages: 26
Registered: July 2009

Junior Member

The following grammar allows to declare an inheritance hierarchy of entities:

grammar myDSL with org.eclipse.xtext.xbase.annotations.XbaseWithAnnotations
	
...

Entity:
	'entity' (name = ID) ('extends' superType = JvmTypeReference)? '{'
		...
		(attribs += Attribute)*;
		...
	'}';
	
...

While code generation for an Entity there is the need to examine if a special attribute exist in one of the superclasses (entities).

So how can I traverse these structure (superclass is a different resource, JvmTypeReference isnt't an 'Entity')?
Is this a matter of scope, model inferrer or something else? Is there a best practice / some examples?

Thanks for any help,
Andreas

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Re: Accessing attributes in different resources [message #1553076 is a reply to message #1553045]

Thu, 08 January 2015 13:37

Karsten Thoms

Messages: 762
Registered: July 2009
Location: Dortmund, Germany

Senior Member

In the case that you have to traverse to the Entity referenced by the superType relationship, you can inject IJvmModelAssociations and use getPrimarySourceElement. But as super type, any Java type would be allowed here, and the method will return null for this case.

The IJvmModelAssociations can be used as long as it is expected that the referenced element originates from the one language. In the case that multiple DSLs are used, the language specific model associations have to be retrieved like this:

		val type = ref.type
		val modelAssociations = (type.eResource as XtextResource).resourceServiceProvider.get(IJvmModelAssociations)
		
		val sourceElem = modelAssociations.getPrimarySourceElement(ref.type)

(this won't be you case)

HTH,
~Karsten

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