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[Edapt] BackwardConverter causes NP upon feature removal [message #1714342]

Wed, 11 November 2015 22:36

Thorsten Schlathölter

Messages: 312
Registered: February 2012
Location: Düsseldorf

Senior Member

Hi,
I experience problems with the reconstruction of a model in case of an attribute removal. I have simply removed an attribute from my meta-model.

Now when I reconstruct a model from a prior version I get a NP exception:

java.lang.NullPointerException
	at org.eclipse.emf.ecore.impl.EClassImpl.getFeatureID(EClassImpl.java:1500)
	at org.eclipse.emf.ecore.impl.MinimalEStoreEObjectImpl.eDerivedStructuralFeatureID(MinimalEStoreEObjectImpl.java:264)
	at org.eclipse.emf.ecore.impl.BasicEObjectImpl.eSet(BasicEObjectImpl.java:1068)
	at org.eclipse.emf.edapt.internal.migration.internal.BackwardConverter.initProperties(BackwardConverter.java:148)
	at org.eclipse.emf.edapt.internal.migration.internal.BackwardConverter.initProperties(BackwardConverter.java:117)
	at org.eclipse.emf.edapt.internal.migration.internal.BackwardConverter.convert(BackwardConverter.java:61)

And the reason is that the resolveFeature call in the code below (BackwardConverter) here does not find an attribute. And the call

eObject.eSet(targetFeature, element.get(sourceFeature));

gets executed on a null targetFeature. I have the feeling that it should be OK to find no feature in the target if it was removed for the target version.

final EStructuralFeature sourceFeature = slot.getEFeature();
			final EStructuralFeature targetFeature = resolveFeature(sourceFeature);
			if (ignore(sourceFeature)) {
				continue;
			}
			if (slot instanceof AttributeSlot) {
				if (sourceFeature.getEType() instanceof EEnum) {
					final AttributeSlot attributeSlot = (AttributeSlot) slot;
					if (sourceFeature.isMany()) {
						final EList values = (EList) eObject.eGet(targetFeature);
						for (final Object value : attributeSlot.getValues()) {
							values.add(resolveLiteral((EEnumLiteral) value));
						}
					} else {
						if (!attributeSlot.getValues().isEmpty()) {
							eObject.eSet(targetFeature,
								resolveLiteral((EEnumLiteral) attributeSlot
									.getValues().get(0)));
						}
					}
				} else {
					eObject.eSet(targetFeature, element.get(sourceFeature));
				}
			}

Could this be a bug or might I be doing something wrong?

Regards,
Thorsten

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Re: [Edapt] BackwardConverter causes NP upon feature removal [message #1714388 is a reply to message #1714342]

Thu, 12 November 2015 10:29

Thorsten Schlathölter

Messages: 312
Registered: February 2012
Location: Düsseldorf

Senior Member

The above error occurs if I do not release the latest change. If I release, I get a DiagnosticException saying that the feature that I have removed is not a valid feature of the class. Which is actually true because it was removed. Does anybody have positive experience with removing features from a model?

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Re: [Edapt] BackwardConverter causes NP upon feature removal [message #1714393 is a reply to message #1714388]

Thu, 12 November 2015 10:55

Johannes Faltermeier

Messages: 101
Registered: December 2013

Senior Member

Hi Thorsten,

Try using the "Delete Feature" operation from the Edapt "Operation Browser" View. This should work.
If you are simply deleting it using the ecore editor only the metamodel can be updated correctly by Edapt. The model-instances still have values for the deleted feature, so they do not conform to the updated metamodel anymore. The Delete Feature operation also includes the required migration code for model-instances to remove the values.

Cheers
Johannes

Johannes Faltermeier

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