Ok, I could use relationships instead of inheritance. From what I understand
Project would have to be defined as a dynamic virtual entity because a virtual
entity can't link to static entities.
When I talk about adding a static entity, I was wondering if it would be
possible to have your Project as an existing entity (either static or
dynamic) and instead of using inheritance, manage extension through a
relationship to other objects.
e.g. Project could have a 1-1 relationship to a class that represented the
extra attributes in SubProject (or MiniProject, TempProject etc) and then
you would add some logic to Project to make determining what kind of project
you were in easy and some logic to make it transparent when you try to
access attributes.
-Tom
On Mon, Dec 10, 2012 at 3:49 PM, Harpreet Singh <hsingh9@xxxxxxxxx
<mailto:hsingh9@xxxxxxxxx>> wrote:
Tom,
Users would be adding SubProject. SubProject may include additional
attributes that do not exist in Project. Users may add multiple children
under Project: SubProject, MiniProject, TempProject, etc...
Could you please explain how to "create a static entity that has a
One-to-One with the dynamic entity and hide relationship in your getters and
setters"? From what I can see dynamic entities can only have relationships
to other dynamic entities.
Hi Harpreet,
Would would your users be adding in SubProject? How would it be
different
from a Project with some virtual attributes?
-Tom
On Tue, Nov 13, 2012 at 3:14 PM, Harpreet Singh <hsingh9@xxxxxxxxx
<mailto:hsingh9@xxxxxxxxx>> wrote:
Tom, thanks for all your help. Can you expand on what you mean by create
a static entity with a one-to-one with the dynamic entity? How would
that work?
Hi Harpreet,
Currently Dynamic entities are implemented using weaving and the
weaving support will not take into account a parent class other than
DynamicEntityImpl. As a result, I'm afraid you won't be able to
create a dynamic entity that is a subclass of an existing entity.
Please feel free to add an enhancement request.
Perhaps you can, instead create a static entity that has a
One-to-One with the dynamic entity and hide relationship in your
getters and setters.
-Tom
On Mon, Nov 12, 2012 at 12:00 PM, Harpreet Singh <hsingh9@xxxxxxxxx
<mailto:hsingh9@xxxxxxxxx>> wrote:
Hi Tom,
I'm looking for both. In my project I have a entity called
Project, which is extensible and uses VirtualAccessMethods. Using
this and XMLMetaDataSource I allow my user to add new attributes to
the project entity. Now I want to go further and allow the user to
create a SubProject entity for example. This new dynamic entity
created by the user would extend entities that I ship, e.g. Project.
I thought I could use DynamicEntities to achieve this. However, it
seems Project would have to extend DynamicEntityImpl and implement
the fetchPropertiesManager method, which I'm not sure how to do. Is
this the only way to do this in eclipselink?
Hi Harpreet,
Are you looking for a dynamic entity, or just an extensible
entity?
DynamicEntities must extend DynamicEntityImpl. Any entity
can be extensible.
See:
http://wiki.eclipse.org/EclipseLink/Examples/JPA/Extensibility
<http://wiki.eclipse.org/EclipseLink/Examples/JPA/Extensibility>
-Tom
On Thu, Nov 8, 2012 at 2:38 PM, Harpreet Singh <hsingh9@xxxxxxxxx
<mailto:hsingh9@xxxxxxxxx>> wrote:
Tom,
I get a little further with the latest 2.4.2 milestone. Now I
get the error below. I guess this means that my user definable
dynamic entity cannot extend something I ship in the product. Is
there any other way to achieve this inheritance? I want the
dynamic entity to extend the entity I ship with the product,
which is not a dynamic entity.
Caused by: java.lang.IllegalArgumentException:
DynamicClassLoader: com.foo.Project not compatible with parent
class org.eclipse.persistence.internal.dynamic.DynamicEntityImpl
at
org.eclipse.persistence.dynamic.DynamicClassLoader.checkAssignable(DynamicClassLoader.java:174)
at
org.eclipse.persistence.dynamic.DynamicClassLoader.createDynamicClass(DynamicClassLoader.java:167)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProject.createDynamicClass(MetadataProject.java:844)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProject.createDynamicClass(MetadataProject.java:838)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProject.createDynamicClass(MetadataProject.java:838)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProject.createDynamicClasses(MetadataProject.java:865)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProcessor.createDynamicClasses(MetadataProcessor.java:153)
at
org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:469)
... 60 more
On Tue, Nov 6, 2012 at 5:30 PM, Harpreet Singh
<hsingh9@xxxxxxxxx <mailto:hsingh9@xxxxxxxxx>> wrote:
In my project I need to be able to create a dynamic entity
which extends a regular entity. The dynamic/virtual entity
definition is loaded at startup from a configuration
database (not using eclipselink). For this I've created a
XMLMetadataSource which provides eclipselink with the
dynamic entity definition, however startup fails b/c
eclipselink is using the real classloader instead of the
dynamic classloader. I'm using EclipseLink 2.4.0.
Code from Metadatasource:
EntityAccessor accessor = new EntityAccessor();
accessor.setName("SubProject");
//dynamic entity
accessor.setClassName("com.foo.SubProject");
//regular entity, see com/foo/Project.java
accessor.setParentClassName("com.foo.Project");
accessor.setAccess("VIRTUAL");
accessor.setDiscriminatorValue("SP");
List<SecondaryTableMetadata> secondaryTables = new
ArrayList<SecondaryTableMetadata>();
SecondaryTableMetadata table = new
SecondaryTableMetadata();
table.setName("pln_sub_project");
secondaryTables.add(table);
accessor.setSecondaryTables(secondaryTables);
//based on Metadatasource example
addExtension(accessor, new
Extension("com.foo.SubProject", "java.lang.String", "foo"));
mappings.getEntities().add(accessor);
The problem seems to be here in
EntityManagerSetupImpl#deploy(Classloader, Map)
processor.setClassLoader(realClassLoader);
processor.createDynamicClasses();
The processor ends up using the realClassLoader instead of
the dynamic class loader supplied in PersistenceUnit
properties resulting in the following error:
Caused by: Exception [EclipseLink-28019] (Eclipse
Persistence Services - 2.4.0.v20120608-r11652):
org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Deployment of PersistenceUnit [p]
failed. Close all factories for this PersistenceUnit.
Internal Exception: Exception [EclipseLink-7328] (Eclipse
Persistence Services - 2.4.0.v20120608-r11652):
org.eclipse.persistence.exceptions.ValidationException
Exception Description: When using VIRTUAL access a
DynamicClassLoader must be provided when creating the entity
manager factory using the eclipselink property
[eclipselink.classloader]. That is,
createEntityManagerFactory(String persistenceUnitName, Map
properties) and add a new DynamicClassLoader() to the Map
properties.
at
org.eclipse.persistence.exceptions.EntityManagerSetupException.deployFailed(EntityManagerSetupException.java:229)
... 62 more
Caused by: Exception [EclipseLink-7328] (Eclipse Persistence
Services - 2.4.0.v20120608-r11652):
org.eclipse.persistence.exceptions.ValidationException
Exception Description: When using VIRTUAL access a
DynamicClassLoader must be provided when creating the entity
manager factory using the eclipselink property
[eclipselink.classloader]. That is,
createEntityManagerFactory(String persistenceUnitName, Map
properties) and add a new DynamicClassLoader() to the Map
properties.
at
org.eclipse.persistence.exceptions.ValidationException.invalidClassLoaderForDynamicPersistence(ValidationException.java:1070)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProject.createDynamicClasses(MetadataProject.java:861)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProcessor.createDynamicClasses(MetadataProcessor.java:153)
at
org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:463)
... 60 more
[EL Severe]: ejb: 2012-11-06
17:17:42.19--ServerSession(29272897)--Thread(Thread[http-bio-8080-exec-3,5,main])--Local
Exception Stack:
Exception [EclipseLink-7328] (Eclipse Persistence Services -
2.4.0.v20120608-r11652):
org.eclipse.persistence.exceptions.ValidationException
Exception Description: When using VIRTUAL access a
DynamicClassLoader must be provided when creating the entity
manager factory using the eclipselink property
[eclipselink.classloader]. That is,
createEntityManagerFactory(String persistenceUnitName, Map
properties) and add a new DynamicClassLoader() to the Map
properties.
at
org.eclipse.persistence.exceptions.ValidationException.invalidClassLoaderForDynamicPersistence(ValidationException.java:1070)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProject.createDynamicClasses(MetadataProject.java:861)
at
org.eclipse.persistence.internal.jpa.metadata.MetadataProcessor.createDynamicClasses(MetadataProcessor.java:153)
at
org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:463)
at
org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getDatabaseSession(EntityManagerFactoryDelegate.java:186)
at
org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getMetamodel(EntityManagerFactoryDelegate.java:602)
at
org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getMetamodel(EntityManagerFactoryImpl.java:516)
_______________________________________________
eclipselink-users mailing list
eclipselink-users@xxxxxxxxxxx
https://dev.eclipse.org/mailman/listinfo/eclipselink-users
