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Evaluation of derived OCL Ecore attributes from Java [message #1791710]

Wed, 04 July 2018 12:30

Matteo MORELLI

Messages: 5
Registered: July 2018

Junior Member

Hello, I'm dealing with a problem with the evaluation of derived Ecore attributes from Java. The derivation rule is annotated in the Ecore metamodel as OCL expression.

My use case matches very well what is described here: https://bugs.eclipse.org/bugs/show_bug.cgi?id=420208 (which comes from a thread here: https://www.eclipse.org/forums/index.php/t/561711/).

It seems that this is not really a bug, but rather bad user initialization. However, I do not understand what to do to workaround the problem.

I made an effort to read about possible solutions. That's what I tried:

make sure that Operation Reflection is true
explicit Use Delegates = true as annotation
Used the following initialization to comply with this statement "SettingDelegateFactory registration must occur before the static initialization of the EMF generated classes" (from https://bugs.eclipse.org/bugs/show_bug.cgi?id=420208)
```
String oclDelegateURI = OCLDelegateDomain.OCL_DELEGATE_URI;
EStructuralFeature.Internal.SettingDelegate.Factory.Registry.INSTANCE.put(oclDelegateURI,
    new OCLSettingDelegateFactory.Global());
```
tried to adopt the solution suggested here https://www.eclipse.org/forums/index.php?t=msg&th=526868&goto=1112295&#msg_1112295 (seems to not be compatible with Oxygen)

You can find here attached (i) a EMF project with a simple metamodel embedding OCL expressions to define derived attributes and (ii) a plugin that shows how I currently do model queries (from Java). The plugin also contains a model instance which conforms to the metamodel (in models/). What I get is, for example, that once I try to access

ca.getModel()

(line 42 in com.test.javaload.dummy.loader.DummyModelLoader) I always get a NPE.

Any suggestion on how to get it working?
Thanks in advance
--
Matteo

Attachment: emf_project.zip
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Attachment: plugin_model_queries.zip
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