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Home » Modeling » EMF "Technology" (Ecore Tools, EMFatic, etc)  » [Teneo] Abstract classes in top entities
[Teneo] Abstract classes in top entities [message #113043] Sat, 23 February 2008 11:38 Go to next message
André Lahs is currently offline André LahsFriend
Messages: 4
Registered: July 2009
Junior Member
Hi,

I am currently investigating Teneo with Hibernate. Especially the lazy
loading possibilities are very interesting for me.

My meta model is quite simple. There is a model class which contains
packages and packages can also contain packages. Both model and package
classes extend an abstract class namedElement. On resource loading I
expected the containment references to be lazily loaded.

While testing I noticed that all objects (model and packages) were loaded
on initial resource loading. First, I thought it was an configuration
issue. But it wasn't. I debugged the HibernateResource and found out, that
it loads all "topEntities" at once. The problem is, that all objects of
type namedElement where recognized as topEntities, since namedElements are
not contained by any other class. For this reason all packages where
loaded immediately.

After changing the computeTopEntities() method of HbDataStore class, it
worked the expected way.

protected String[] computeTopEntities() {
final ArrayList<String> result = new ArrayList<String>();
for (Iterator<?> pcs = getClassMappings(); pcs.hasNext();) {
final PersistentClass pc = (PersistentClass) pcs.next();
...
if (topEntity && !pc.isAbstract()) { // added not abstract condition
result.add(getMappedName(pc));
}
}
return result.toArray(new String[result.size()]);
}

Is there another possibility to control the topEntities computation?

Are there any drawbacks with the solution above? Otherwise I would
suggest, that this becomes the default behavior.

With regards, André
Re: [Teneo] Abstract classes in top entities [message #113064 is a reply to message #113043] Sun, 24 February 2008 10:02 Go to previous message
Martin Taal is currently offline Martin TaalFriend
Messages: 5468
Registered: July 2009
Senior Member
Hi André,
I see your point. The problem is effectively a bit larger, in fact any superclass which is
non-contained which has contained-sub-classes will result in instances of contained-sub-classes to
be loaded in the resource. However this more general issue is hard to solve and the
hibernateresource load behavior can be customized
( http://www.elver.org/hibernate/hibernateresources.html#Custo mizing+load+behavior).

But for the case you mention (abstract superclasses) I agree that the topentities computation should
not consider abstract superclasses as topentities. It should just look at concrete subclasses.
Can you enter a bugzilla for this with just a copy of your post in it? Then I will incorporate this
in the next build (within a few weeks from now).

gr. Martin

André Lahs wrote:
> Hi,
>
> I am currently investigating Teneo with Hibernate. Especially the lazy
> loading possibilities are very interesting for me.
>
> My meta model is quite simple. There is a model class which contains
> packages and packages can also contain packages. Both model and package
> classes extend an abstract class namedElement. On resource loading I
> expected the containment references to be lazily loaded.
>
> While testing I noticed that all objects (model and packages) were
> loaded on initial resource loading. First, I thought it was an
> configuration issue. But it wasn't. I debugged the HibernateResource and
> found out, that it loads all "topEntities" at once. The problem is, that
> all objects of type namedElement where recognized as topEntities, since
> namedElements are not contained by any other class. For this reason all
> packages where loaded immediately.
> After changing the computeTopEntities() method of HbDataStore class, it
> worked the expected way.
>
> protected String[] computeTopEntities() {
> final ArrayList<String> result = new ArrayList<String>();
> for (Iterator<?> pcs = getClassMappings(); pcs.hasNext();) {
> final PersistentClass pc = (PersistentClass) pcs.next();
> ...
> if (topEntity && !pc.isAbstract()) { // added not abstract condition
> result.add(getMappedName(pc));
> }
> }
> return result.toArray(new String[result.size()]);
> }
>
> Is there another possibility to control the topEntities computation?
>
> Are there any drawbacks with the solution above? Otherwise I would
> suggest, that this becomes the default behavior.
>
> With regards, André
>


--

With Regards, Martin Taal

Springsite/Elver.org
Office: Hardwareweg 4, 3821 BV Amersfoort
Postal: Nassaulaan 7, 3941 EC Doorn
The Netherlands
Tel: +31 (0)84 420 2397
Fax: +31 (0)84 225 9307
Mail: mtaal@springsite.com - mtaal@elver.org
Web: www.springsite.com - www.elver.org
Re: [Teneo] Abstract classes in top entities [message #615547 is a reply to message #113043] Sun, 24 February 2008 10:02 Go to previous message
Martin Taal is currently offline Martin TaalFriend
Messages: 5468
Registered: July 2009
Senior Member
Hi André,
I see your point. The problem is effectively a bit larger, in fact any superclass which is
non-contained which has contained-sub-classes will result in instances of contained-sub-classes to
be loaded in the resource. However this more general issue is hard to solve and the
hibernateresource load behavior can be customized
( http://www.elver.org/hibernate/hibernateresources.html#Custo mizing+load+behavior).

But for the case you mention (abstract superclasses) I agree that the topentities computation should
not consider abstract superclasses as topentities. It should just look at concrete subclasses.
Can you enter a bugzilla for this with just a copy of your post in it? Then I will incorporate this
in the next build (within a few weeks from now).

gr. Martin

André Lahs wrote:
> Hi,
>
> I am currently investigating Teneo with Hibernate. Especially the lazy
> loading possibilities are very interesting for me.
>
> My meta model is quite simple. There is a model class which contains
> packages and packages can also contain packages. Both model and package
> classes extend an abstract class namedElement. On resource loading I
> expected the containment references to be lazily loaded.
>
> While testing I noticed that all objects (model and packages) were
> loaded on initial resource loading. First, I thought it was an
> configuration issue. But it wasn't. I debugged the HibernateResource and
> found out, that it loads all "topEntities" at once. The problem is, that
> all objects of type namedElement where recognized as topEntities, since
> namedElements are not contained by any other class. For this reason all
> packages where loaded immediately.
> After changing the computeTopEntities() method of HbDataStore class, it
> worked the expected way.
>
> protected String[] computeTopEntities() {
> final ArrayList<String> result = new ArrayList<String>();
> for (Iterator<?> pcs = getClassMappings(); pcs.hasNext();) {
> final PersistentClass pc = (PersistentClass) pcs.next();
> ...
> if (topEntity && !pc.isAbstract()) { // added not abstract condition
> result.add(getMappedName(pc));
> }
> }
> return result.toArray(new String[result.size()]);
> }
>
> Is there another possibility to control the topEntities computation?
>
> Are there any drawbacks with the solution above? Otherwise I would
> suggest, that this becomes the default behavior.
>
> With regards, André
>


--

With Regards, Martin Taal

Springsite/Elver.org
Office: Hardwareweg 4, 3821 BV Amersfoort
Postal: Nassaulaan 7, 3941 EC Doorn
The Netherlands
Tel: +31 (0)84 420 2397
Fax: +31 (0)84 225 9307
Mail: mtaal@springsite.com - mtaal@elver.org
Web: www.springsite.com - www.elver.org
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