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Home » Modeling » EMF "Technology" (Ecore Tools, EMFatic, etc)  » ClassCastException to EList
ClassCastException to EList [message #618077] Tue, 20 May 2008 21:06
Eclipse UserFriend
Originally posted by:


I am currently conducting some research on how to maybe change the
software development workflow and structure in my institute. As I do
not like too suffocating solutions I thought about some modelling
approach through EMF, Teneo and DataNucleus.

So I got myself everything needed, read all guides I could find on, and and started with a basic
model with basic relations. Everything worked so far as that I could
- build the model (the example model from this site orial.html),
- create the genmodel,
- generated the code and even the
- package.jdo.
Everything got enhanced and then I thought I could start persisting
everything... so I thought. All the time I get the error:
java.lang.ClassCastException: org.datanucleus.sco.List cannot be cast
to org.eclipse.emf.common.util.EList

I looked it up, searched the newslists and forums but I couldn't figure
out the solution. I know that there is probably an error about the
implementing SCO for EList and DataNucleus, but I cannot figure out
how to tell him what to use. I found tutorials about extensions and
tried that but maybe I am just to slow for that. I do not really get the

The code is plain simple I think:

PersistenceManagerFactory pmf = JDOHelper.getPersistenceManagerFactory(" ");
PersistenceManager pm = pmf.getPersistenceManager();

Transaction tx = pm.currentTransaction();
try {

DataModel datamodel = DataFactory.eINSTANCE.createDataModel();



} finally {
if(tx.isActive()) {

The tables are created in the database (a test MySQL DB). But
pm.makePersistent(datamodel); kicks him out with the exception.

I tried the creation with

JpoxDataStore jpoxDataStore = JpoxHelper.INSTANCE.createRegisterDataStore("Data");

but that throws errors from the beginning, as I think maybe something
changed from Jpox to DataNucleus. So I tried older versions, before
DataNucleus, so with Jpox directly, then the jpoxDataStore.initialize();
keeps getting errors.

As you can see I am very desperate at the moment and I hope anyone can help me.

Many many thanks in advance and thanks for every response.


PS: I am using Eclipse 3.4M7 (but I have different installations
with different plugins running, for testing purposes),
EMF 2.4.0v200805052017 and Teneo 0.8.0v200804231747 with DataNucleus 1.0.0m1.

The ecore model is following, the rest is generated through the described plugins
plus my Test Class up above:

<?xml version="1.0" encoding="UTF-8"?>
<ecore:EPackage xmi:version="2.0"
xmlns:xmi="" xmlns:xsi=""
xmlns:ecore="" name="data"
nsURI="" nsPrefix="data">
<eClassifiers xsi:type="ecore:EClass" name="DataModel">
<eStructuralFeatures xsi:type="ecore:EAttribute" name="name" eType="ecore:EDataType"/>
<eStructuralFeatures xsi:type="ecore:EReference" name="entity" upperBound="-1"
eType="#//Entity" containment="true"/>
<eClassifiers xsi:type="ecore:EClass" name="Entity">
<eStructuralFeatures xsi:type="ecore:EAttribute" name="name" eType="ecore:EDataType"/>
<eStructuralFeatures xsi:type="ecore:EReference" name="attribute" lowerBound="1"
upperBound="-1" eType="#//Attribute" containment="true"/>
<eStructuralFeatures xsi:type="ecore:EReference" name="reference" upperBound="-1"
eType="#//EntityReference" containment="true"/>
<eClassifiers xsi:type="ecore:EClass" name="Attribute">
<eStructuralFeatures xsi:type="ecore:EAttribute" name="name" eType="ecore:EDataType"/>
<eStructuralFeatures xsi:type="ecore:EAttribute" name="type" eType="ecore:EDataType"/>
<eClassifiers xsi:type="ecore:EClass" name="EntityReference">
<eStructuralFeatures xsi:type="ecore:EAttribute" name="name" eType="ecore:EDataType"/>
<eStructuralFeatures xsi:type="ecore:EAttribute" name="toMany" eType="ecore:EDataType"/>
<eStructuralFeatures xsi:type="ecore:EReference" name="target" lowerBound="1"
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