Eclipse Community Forums: TMF (Xtext) » Re: Could not serialize EObject via backtracking.

Help

Home

Home » Modeling » TMF (Xtext) » Re: Could not serialize EObject via backtracking.

Show: Today's Messages :: Show Polls :: Message Navigator

Re: Could not serialize EObject via backtracking. [message #721272]

Thu, 01 September 2011 09:53

Moritz Eysholdt

Messages: 161
Registered: July 2009
Location: Kiel, Germany

Senior Member

Hi Steven,

long time no see. Hope you're doing fine.

You object "EntityModel" can not be matched by the constraint
---
module=[Module|QualifiedName] version=STRING entities+=Entity+
---

you can understand the constraint in the same way as an Xtext grammar.

The error message does not say (yet) why exactly the object can not be
matched. Possible reasons are:
- the cross reference can not be serialized
- the cross reference is not set
- entities is empty
- value conversion for version STRING fails.

Could you dump your model using EmfFormatter.objToStr() before you
serialize it?

regards,
Moritz

On 01.09.11 11:40, steven reinisch wrote:
> hi,
>
> based on the following grammar:
>
>
> EntityModel returns system::EntityModel:
> 'entities for module' module = [system::Module | QualifiedName]
> 'version' version = STRING (entities += Entity)+
> ;
>
> Entity returns modulob::Entity:
> (annotations+=Annotation)*
> (isAbstract?='abstract')? 'entity' name=ID (':'
> super=[modulob::Entity])?'{'
> (features+=Feature)*
> '}'
> ;
>
>
> I am manipulating (changing the 'version') this model in memory:
>
>
> entities for module iPhoneApp.Reporting version "1.0"
>
> entity AnEntity {
>
> }
>
>
> and then trying to serialize the in-memory representation. But the
> serialization fails with this exception:
>
>
> java.lang.RuntimeException: Could not serialize EObject via backtracking.
> Constraint: (null) module=[Module|QualifiedName] version=STRING
> entities+=Entity+ (null)
> Semantic Object: EntityModel
> Context: EntityModel
> at
> org.eclipse.xtext.serializer.diagnostic.ISerializationDiagnostic$ExceptionThrowingAcceptor.accept(ISerializationDiagnostic.java:66)
>
> at
> org.eclipse.xtext.serializer.sequencer.BacktrackingSemanticSequencer.createSequence(BacktrackingSemanticSequencer.java:418)
>
> at
> de.dubmas.modulob.serializer.AbstractDataDslSemanticSequencer.sequence_EntityModel(AbstractDataDslSemanticSequencer.java:176)
>
> at
> de.dubmas.modulob.serializer.AbstractDataDslSemanticSequencer.createSequence(AbstractDataDslSemanticSequencer.java:107)
>
> at
> org.eclipse.xtext.serializer.impl.Serializer.serialize(Serializer.java:76)
> at
> org.eclipse.xtext.serializer.impl.Serializer.serialize(Serializer.java:84)
> at
> org.eclipse.xtext.serializer.impl.Serializer.serialize(Serializer.java:106)
> at
> org.eclipse.xtext.resource.XtextResource.doSave(XtextResource.java:286)
>
>
> I have no clue how to fix this. Does anyone have a suggestion?
>
> regards,
>
> steven

Report message to a moderator

Re: Could not serialize EObject via backtracking. [message #721332 is a reply to message #721272]

Thu, 01 September 2011 13:44

steven reinisch

Messages: 33
Registered: July 2009

Member

hi moritz,

as long as I can work with xtext I'm fine Smile

.

I can dump my object with EmfFormatter.objToStr():

EntityModel {
    attr EString version '1.0'
    cref Entity entities [
        0: Entity {
            attr EString name 'AnEntity'
        }
    ]
    ref Module module ref: Module@platform:/resource/iPhoneApp/src/iPhoneApp/iPhoneApp.mosys#//@modules.0
}

The cross reference is set and 'entities' is not empty.

How can check if value conversion for version STRING fails or the cross reference cannot be serialized?

regards,

steven

Report message to a moderator

Re: Could not serialize EObject via backtracking. [message #721391 is a reply to message #721332]

Thu, 01 September 2011 15:53

Moritz Eysholdt

Messages: 161
Registered: July 2009
Location: Kiel, Germany

Senior Member

Hi Steven,

for the backtracking algorithm, you can check in the debugger whether
org.eclipse.xtext.serializer.sequencer.BacktrackingSemanticSequencer.TraceItem.cloneAndConsume(ISemState)
returns null for an assignment that should actually be serialized.
This also covers the value conversion scenario.

Another possible cause is that your TransientValueService determines a
value to be transient even though it's needed by the grammar.

regards,
Moritz

On 01.09.11 15:44, steven reinisch wrote:
> hi moritz,
>
> as long as I can work with xtext I'm fine :) .
>
> I can dump my object with EmfFormatter.objToStr():
>
>
> EntityModel {
> attr EString version '1.0'
> cref Entity entities [
> 0: Entity {
> attr EString name 'AnEntity'
> }
> ]
> ref Module module ref:
> Module@platform:/resource/iPhoneApp/src/iPhoneApp/iPhoneApp.mosys#//@modules.0
>
> }
>
>
> The cross reference is set and 'entities' is not empty.
>
> How can check if value conversion for version STRING fails or the cross
> reference cannot be serialized?
>
> regards,
>
> steven
>

Report message to a moderator

Re: Could not serialize EObject via backtracking. [message #721566 is a reply to message #721391]

Fri, 02 September 2011 06:35

steven reinisch

Messages: 33
Registered: July 2009

Member

hi moritz,

I checked the debugger and TraceItem.cloneAndConsume(ISemState) returns null for the crossreference to a Module instance:

public TraceItem cloneAndConsume(ISemState state) {
   int index = nextIndex[state.getFeatureID()];
   if (index >= obj.getValueCount(state.getFeatureID()))
      return null;//program exists at this branch

...
}

So, how can I fix this issue?

thx,

steven

Report message to a moderator

Re: Could not serialize EObject via backtracking. [message #721609 is a reply to message #721566]

Fri, 02 September 2011 09:31

Moritz Eysholdt

Messages: 161
Registered: July 2009
Location: Kiel, Germany

Senior Member

hi Steven,

could you check if "obj.getValueCount(state.getFeatureID())" has
returned 0 in the scenario that you have described below?

If that is true, the serializer assumes that no values for "module" are
available because the TransientValueService has marked the EReference as
transient in
org.eclipse.xtext.serializer.sequencer.BacktrackingSemanticSequencer.SerializableObject.SerializableObject(EObject,
INodesForEObjectProvider)

regards,
Moritz

On 02.09.11 08:35, steven reinisch wrote:
> hi moritz,
>
> I checked the debugger and TraceItem.cloneAndConsume(ISemState) returns
> null for the crossreference to a Module instance:
>
>
> public TraceItem cloneAndConsume(ISemState state) {
> int index = nextIndex[state.getFeatureID()];
> if (index >= obj.getValueCount(state.getFeatureID()))
> return null;//program exists at this branch
>
> ..
> }
>
>
> So, how can I fix this issue?
>
> thx,
>
> steven

Report message to a moderator

Re: Could not serialize EObject via backtracking. [message #721615 is a reply to message #721609]

Fri, 02 September 2011 10:26

steven reinisch

Messages: 33
Registered: July 2009

Member

Moritz Eysholdt wrote on Fri, 02 September 2011 05:31

hi Steven,

could you check if "obj.getValueCount(state.getFeatureID())" has
returned 0 in the scenario that you have described below?

If that is true, the serializer assumes that no values for "module" are
available because the TransientValueService has marked the EReference as
transient in
org.eclipse.xtext.serializer.sequencer.BacktrackingSemanticSequencer.SerializableObject.SerializableObject(EObject,
INodesForEObjectProvider)

That was the hint! The EReference 'module' had 'Transient = true' in my .ecore.
Changing it to 'false' lets the serialization run smoothly!

I owe you a beer moritz! .. saved my weekend Smile

regards,

steven

Report message to a moderator

Previous Topic:	[Serializer 2.0] Hidden Tokens?
Next Topic:	[Xtend2] How to integrate a Java Bufferedreader in *.xtend file

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

]

Current Time: Tue Apr 23 14:47:17 GMT 2024

.:: Contact :: Home ::.

Breadcrumbs

Sign up to our Newsletter