Home » Modeling » EMF » [Teneo][Hibernate] ClassCastException: HibernatePersistableEList cannot be cast to BasicEList
| [Teneo][Hibernate] ClassCastException: HibernatePersistableEList cannot be cast to BasicEList [message #875388] |
Tue, 22 May 2012 16:43  |
 Markus Gulden
Messages: 5
Registered: May 2012 |
Junior Member |
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Hi there,
I have a simple EMF model, consisting of two types, Type1 and Type2. Type1 has a 1-*-reference called list on Type2.
In the generated code, normally, I would get a getter like
public EList getList() {
if (list == null) {
list = new EObjectResolvingEList(Type2.class, this, Root_packagePackage.TYPE1__LIST);
}
return list;
}
Since I need a non-generic field for an XTend based code generator, I changed the Array Accessors property in my GenModel to "true", and now I have a getter like
public Type2[] getList() {
if (list == null || list.isEmpty()) return LIST_EEMPTY_ARRAY;
BasicEList list = (BasicEList)list;
list.shrink();
return (Type2[])list.data();
}
For my generator, this works fine, but when I query a persisted object of Type1 via Teneo and Hibernate and access the Type2 field, in line
BasicEList list = (BasicEList)list;
I get the exception
java.lang.ClassCastException: org.eclipse.emf.teneo.hibernate.mapping.elist.HibernatePersistableEList cannot be cast to org.eclipse.emf.common.util.BasicEList
If I would change the BasicEList manually to EList, it works, but I think, this is not a real option.
Does anybody have an idea to solve this problem of incompatible types?
[Updated on: Tue, 22 May 2012 17:15] Report message to a moderator |
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| Re: [Teneo][Hibernate] [message #875420 is a reply to message #875388] |
Tue, 22 May 2012 18:11  |
Martin Taal
Messages: 5468
Registered: July 2009 |
Senior Member |
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He Markus,
Why is it not an option to cast to EList?
It is not so easy to change this the persistableelist inherits from the DelegatingEcoreElist not from BasicElist.
gr. Martin
On 05/22/2012 06:43 PM, Markus Gulden wrote:
> Hi there,
>
> I have a simple EMF model, consisting of two types, Type1 and Type2. Type1 has a 1-*-reference called list on Type2.
>
> In the generated code, normally, I would get a getter like
>
> public EList getList() {
> if (list == null) {
> list = new EObjectResolvingEList(Type2.class, this, Root_packagePackage.TYPE1__LIST);
> }
> return list;
> }
>
> Since I need a non-generic field for an XTend based code generator, I changed the Array Accessors property in my
> GenModel to "true", and now I have a getter like
>
> public Type2[] getList() {
> if (list == null || list.isEmpty()) return LIST_EEMPTY_ARRAY;
> BasicEList list = (BasicEList)list;
> list.shrink();
> return (Type2[])list.data();
> }
>
> For my generator, this works fine, but when I query a persisted object of Type1 via Teneo and Hibernate and access the
> Type2 field, in line
>
> BasicEList list = (BasicEList)list;
> I get the exception
>
> java.lang.ClassCastException: org.eclipse.emf.teneo.hibernate.mapping.elist.HibernatePersistableEList cannot be cast to
> org.eclipse.emf.common.util.BasicEList
>
> If I change the BasicEList manually to EList, it works, but I think, this is not a real option.
>
> Does anybody have an idea to solve this problem?
--
With Regards, Martin Taal
Springsite/Elver.org
Office: Hardwareweg 4, 3821 BV Amersfoort
Postal: Nassaulaan 7, 3941 EC Doorn
The Netherlands
Cell: +31 (0)6 288 48 943
Tel: +31 (0)84 420 2397
Fax: +31 (0)84 225 9307
Mail: mtaal@xxxxxxxx - mtaal@xxxxxxxx
Web: www.springsite.com - www.elver.org
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| Re: [Teneo][Hibernate] [message #875746 is a reply to message #875709] |
Wed, 23 May 2012 09:08 |
Martin Taal
Messages: 5468
Registered: July 2009 |
Senior Member |
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Hi Markus,
Ha sorry you are right this is EMF generated code... The reality is that I have not encountered anyone using this array
feature with Teneo, so it was never taken into account... It will be quite difficult to support this, as Teneo's EList
use the DelegatingEcoreList. So I am afraid that you can't use this Teneo in this scenario.
gr. Martin
On 05/23/2012 09:59 AM, Tom Schindl wrote:
> Because EList doesn't have the shrink() method which is called so that
> data() returns the correct result.
>
> I guess the reason not to use List.toArray() is performance. The code
> trys to avoid the copying - what worries me about the generated method
> is that data returns the internal data structure so one could modify a
> BasicEList without any event getting triggered but maybe that's
> intentional behavior?
>
> Maybe the code generator could be changed to something like this:
>
> public Type2[] getList() {
> if (list == null || list.isEmpty()) return LIST_EEMPTY_ARRAY;
> if( list instanceof BasicEList) {
> BasicEList list = (BasicEList)list;
> list.shrink();
> return (Type2[])list.data();
> } else {
> return list.toArray(new Type2[0]);
> }
> }
>
> This would still give you some overhead because of the instance of check
> and the potential that once you get the internal datastructure you can
> modify (if it is an BasicEList) and a copy of its not an BasicEList.
>
> I'm still not sure why you need to have Type2[] because when generating
> Java5 sourcecode you'd get the correct type signature EList<Type2>.
>
> Tom
>
> Am 23.05.12 09:34, schrieb Markus Gulden:
>> Hi Martin,
>>
>> thanks for your reply.
>>
>> Doesn't MDD with code generation aim to make manual coding needless, at
>> least at such basic features like getters?
>>
>> The getters are generated by EMF, forgot to mention that, but I thought
>> that would be clear.
>>
>> I don't know, what of both is the problem, that EMF doesn't use the root
>> type EList, or that the Teneo list doesn't inheritate the BasicEList?
>
--
With Regards, Martin Taal
Springsite/Elver.org
Office: Hardwareweg 4, 3821 BV Amersfoort
Postal: Nassaulaan 7, 3941 EC Doorn
The Netherlands
Cell: +31 (0)6 288 48 943
Tel: +31 (0)84 420 2397
Fax: +31 (0)84 225 9307
Mail: mtaal@xxxxxxxx - mtaal@xxxxxxxx
Web: www.springsite.com - www.elver.org
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