Eclipse Community Forums: TMF (Xtext)

Home » Modeling » TMF (Xtext) » xtext parser node

Thu, 11 November 2010 12:33

Eclipse User

I have an ASTNode that has been loaded from a resource using a standalone setup.

After that, I have code that modifies the ASTNode in memory. (adding some model elements etc.)
I am trying to get the NodeAdapter for the modified ASTNode to obtain some parser node information.
But using the NodeUtil.getNodeAdapter(..) on the modified ASTNode, returns a null.

Is there anyway, I can reconstitute the parser composite node or obtain the node adapter of the modified ASTNode.

I have also tried to use SerializerUtil to serialize the modified ASTNode, but it throws some NPE.

Any ideas?
Thanks!

Re: xtext parser node [message #638705 is a reply to message #638592]

Fri, 12 November 2010 04:39

Eclipse User

Hi,

you should not modify the node model directly but the semantic model
(which can be obtained by means of resource.getContents()). Afterwards
just call resource.save() and the serializer will jump in and recreate a
concrete syntax representation for your model.

Regards,
Sebastian
--
Need professional support for Eclipse Modeling?
Go visit: http://xtext.itemis.com

Am 11.11.10 18:33, schrieb sungam:
> I have an ASTNode that has been loaded from a resource using a
> standalone setup.
>
> After that, I have code that modifies the ASTNode in memory. (adding
> some model elements etc.)
> I am trying to get the NodeAdapter for the modified ASTNode to obtain
> some parser node information.
> But using the NodeUtil.getNodeAdapter(..) on the modified ASTNode,
> returns a null.
>
> Is there anyway, I can reconstitute the parser composite node or obtain
> the node adapter of the modified ASTNode.
>
> I have also tried to use SerializerUtil to serialize the modified
> ASTNode, but it throws some NPE.
>
> Any ideas?
> Thanks!

Re: xtext parser node [message #638782 is a reply to message #638705]

Fri, 12 November 2010 10:06

Eclipse User

So what I do is

1. resource.load(...)
2. result=resource.getParseResult
3. result.getRootASTElement

This EObject is then modified and sometimes even a new EObject is created by merging couple of others using the appropriate factory and ECoreUtil methods.

So essentially its the semantic model getting updated.

(i have also tried to replace the above code, to update on the resource.getContents(), which still has the same error)

Because sometimes a new EObject is created merging from few others, the getResource on the EObject returns a null.

So the have the below code instead, to invoke the serializer:
XtextResource resource = injector.getInstance(XtextResource.class);
String finalDsl = resource.getSerializer().serialize(eObject);

which fails with an exception:

Caused by: java.lang.NullPointerException
at org.eclipse.xtext.scoping.impl.DefaultScopeProvider$2.apply( DefaultScopeProvider.java:69)
at org.eclipse.xtext.scoping.impl.DefaultScopeProvider$2.apply( DefaultScopeProvider.java:67)
at org.eclipse.xtext.util.SimpleCache.get(SimpleCache.java:35)
at org.eclipse.xtext.scoping.impl.DefaultScopeProvider.getScope (DefaultScopeProvider.java:98)
at org.eclipse.xtext.scoping.impl.AbstractDeclarativeScopeProvi der$2.handle(AbstractDeclarativeScopeProvider.java:81)
at org.eclipse.xtext.scoping.impl.AbstractDeclarativeScopeProvi der$2.handle(AbstractDeclarativeScopeProvider.java:71)

Re: xtext parser node [message #639176 is a reply to message #638782]

Mon, 15 November 2010 09:31

Eclipse User

Is this usecase out of scope for current xtext support?

Re: xtext parser node [message #639207 is a reply to message #639176]

Mon, 15 November 2010 10:41

Eclipse User

Hi Sungam,

this usecase is on the scope of the Xtext project. However, you should
not try to use an XtextResource without a ResourceSet. Please have a
look at the FAQ to learn how to use Xtext in a standalone environment.

Regards,
Sebastian
--
Need professional support for Eclipse Modeling?
Go visit: http://xtext.itemis.com

Am 15.11.10 15:31, schrieb sungam:
> Is this usecase out of scope for current xtext support?

Re: xtext parser node [message #639271 is a reply to message #639207]

Mon, 15 November 2010 14:43

Eclipse User

My code for loading the resource is:

XtextResourceSet resourceSet = injector.getInstance(XtextResourceSet.class);
resourceSet.addLoadOption(XtextResource.OPTION_RESOLVE_ALL, true);
Resource resource = resourceSet.createResource(URI.createURI("foo:/dummy.mydsl"));
resource.load(inputStream, resourceSet.getLoadOptions());

which is inline with the Xtext FAQ.

But after that, I recreate a new EObject node from the generated factories merging content from the loaded resource model.

1. MyModel myModelElement = (MyModel)resourceSet.getContents().get(0);
2. MyModel newModelElement = factory.MyDslFactory.eINSTANCE.createMyModel();
3. //here i add content to the 'newModelElement', using values from 'myModelElement'

How can I serialize it back, from the 'newModelElement'?

Re: xtext parser node [message #639375 is a reply to message #639271]

Tue, 16 November 2010 05:09

Eclipse User

Have a look at
http://koehnlein.blogspot.com/2010/06/semantic-model-access- in-xtext.html
Am 15.11.10 20:43, schrieb sungam:
> My code for loading the resource is:
>
> XtextResourceSet resourceSet =
> injector.getInstance(XtextResourceSet.class);
> resourceSet.addLoadOption(XtextResource.OPTION_RESOLVE_ALL, true);
> Resource resource =
> resourceSet.createResource(URI.createURI("foo:/dummy.mydsl"));
> resource.load(inputStream, resourceSet.getLoadOptions());
>
> which is inline with the Xtext FAQ.
>
> But after that, I recreate a new EObject node from the generated
> factories merging content from the loaded resource model.
>
> 1. MyModel myModelElement = (MyModel)resourceSet.getContents().get(0);
> 2. MyModel newModelElement =
> factory.MyDslFactory.eINSTANCE.createMyModel();
> 3. //here i add content to the 'newModelElement', using values from
> 'myModelElement'
>
> How can I serialize it back, from the 'newModelElement'?
>
>

--
Need professional support for Eclipse Modeling?
Go visit: http://xtext.itemis.com

Re: xtext parser node [message #639462 is a reply to message #639375]

Tue, 16 November 2010 11:28

Eclipse User

Thanks for the pointer.

I do not update the model from the editor/ui module, but rather to do some code generation.

What I really need is, if sometimes there are missing links, for elements modeled as cross-references,I need a way to determine what the ID of the missing cross reference is.
Well theres the NodeUtil to get the node adapter that leads me to the composite node.
But having recreated a new EObject, that is no longer accessible.

Re: xtext parser node [message #639872 is a reply to message #639462]

Thu, 18 November 2010 03:42

Eclipse User

The node model is created by the (partial) parser only, So you have to
serialize and reparse after the the model change. For your convenience,
this functionality is bundled in the IDocumentEditor.

Am 16.11.10 17:28, schrieb sungam:
> Thanks for the pointer.
>
> I do not update the model from the editor/ui module, but rather to do
> some code generation.
>
> What I really need is, if sometimes there are missing links, for
> elements modeled as cross-references,I need a way to determine what the
> ID of the missing cross reference is.
> Well theres the NodeUtil to get the node adapter that leads me to the
> composite node. But having recreated a new EObject, that is no longer
> accessible.

--
Need professional support for Eclipse Modeling?
Go visit: http://xtext.itemis.com

Previous Topic:	Cross References & Strings
Next Topic:	"Decision can match input such as "')'" using multiple alternatives: 1, 2"

Goto Forum:

-=] Back to Top [=-

Current Time: Tue Jul 01 02:45:56 EDT 2025

.:: Contact :: Home ::.

Breadcrumbs

Sign up to our Newsletter