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Serialization in xtext [message #1257529]

Wed, 26 February 2014 09:32

Eclipse User

Hi all,
My grammar snippet is something like:

Model:
	"name" name=QualifiedName
	(entities+=Entity | values+=ValueObj)* 
;

The general behaviour required for me is Entity and ValueObj can exist independent of each other and in any order.

But I have one special case where Entity should be created first before ValueObj is created. Because ValueObj refers to Entity in some cases.

While filling my model I am filling Entity first and then ValueObj. But still I get NoEObjectDescription found exception during serialization, which says a particular entity is not present that a ValueObj is referring to.

How can I avoid this?
I want Entity to be serialized first and then ValueObj.

Thanks in advance Smile

Re: Serialization in xtext [message #1257562 is a reply to message #1257529]

Wed, 26 February 2014 10:20

Eclipse User

Hi,

can you please share a unit test or something like that that reproduces the problem
+ all relevant parts of grammar and scoping etc

Re: Serialization in xtext [message #1257700 is a reply to message #1257562]

Wed, 26 February 2014 13:01

Eclipse User

Hi Christian,
As root node for my grammar is Model, so my code snippets looks like:

Model model=ModelFactor.eINSTANCE.createModel();
model.getEntities().add(HERE I AM ADDING THE ENTITY);
// This entity is searched for while creating ValueObj and reference has been added here.
//....

// Then adding this ValueObj to model.

model.getValueObj().add(VALUEOBJ HERE);

return model;

So model is returned from this method.
And I am creating a resource and saving this content in the calling function.

// creation of a resource here, Say "resource"
resource.getContents().add(model);
try{
resource.save(Collections.EMPTY_MAP);
}
catch (...){
}

It throws me NoEobjectdescription found exception as explained above. ValueObj is getting serialized first. May be problem at the line resource.getContents().add(model);

How can I avoid this?

Thanks in advance Smile

Re: Serialization in xtext [message #1257748 is a reply to message #1257700]

Wed, 26 February 2014 14:04

Eclipse User

Hi this should work perfectly but without a reproduce able example it is hard to give any further advice

Re: Serialization in xtext [message #1266506 is a reply to message #1257700]

Fri, 07 March 2014 09:55

Eclipse User

If it helps, the Serialization raising exceptions issue in most cases is due to a ScopeProvider problem (in my limited experience).

Make sure if you designed a custom ScopeProvider that it is registered with bindIScopeProvider (and configureSerializerScopeProvider) in your runtime module.

You can also break under debugger just before the
resource.save(Collections.EMPTY_MAP);
and inspect your model manually under debugger to check the AST node that the exception points to as being in error. The error trace is very long, but right at the top you chould get a pretty precise diagnosis of where to look.

The debugger allows to track issues such as crossrefs pointing to objects in other Resources, or attributes being null due to a forgotten EcoreUtil.copy somewhere etc... as these errors are frequent when building a model programmatically.

gl&hf

yann

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