How do I duplicate a hibernate object?

wildleaf · **Joined:** Sun May 15, 2005 1:24 pm **Posts:** 11

Hi,

What is the easiest way to duplicate a hibernate object including all of its childrens and update it into the database?

THanks a lot.
Henry

max · **Posted:** Fri Jun 10, 2005 1:32 am

replicate?

wildleaf · **Joined:** Sun May 15, 2005 1:24 pm **Posts:** 11

max wrote:

replicate?

Thanks for reply.

It is not replicate. What I need is to make a new hibernate object with a different "id"(primary key), but all other properties are copied from the orignial.

max · **Posted:** Fri Jun 10, 2005 5:24 am

session.replicate() and then nuke the version info manually

zdila · **Posted:** Fri Jun 10, 2005 6:19 am

hi

I have the same problem and I can't solve it using replicate. BTW why to use replicate? Replicate is for making detached object persistent, isn't it?

Code:

Foo foo = session.get(Foo.class, fooId);
// here I'd like to read all properties of the lazy object (what method does that?)
session.evict(foo);
foo.setId(null);
session.save(foo);

this throws an exception:

Code:

ERROR AssertionFailure - an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session)
org.hibernate.AssertionFailure: null identifier
   at org.hibernate.engine.EntityKey.<init>(EntityKey.java:33)
   at org.hibernate.engine.PersistenceContext.reassociateProxy(PersistenceContext.java:518)
   at org.hibernate.engine.PersistenceContext.unproxyAndReassociate(PersistenceContext.java:565)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:65)
   at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:468)
   at org.hibernate.engine.Cascades$5.cascade(Cascades.java:154)
   at org.hibernate.engine.Cascades.cascadeAssociation(Cascades.java:771)
   at org.hibernate.engine.Cascades.cascade(Cascades.java:720)
   at org.hibernate.engine.Cascades.cascade(Cascades.java:847)
   at org.hibernate.event.def.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:332)
   at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:214)
   at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:160)
   at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:108)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:184)
   at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:173)
   at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:69)
   at org.hibernate.impl.SessionImpl.save(SessionImpl.java:481)
   at org.hibernate.impl.SessionImpl.save(SessionImpl.java:476)
essionImpl.java:476)

Please provide a simple example how to clone a persistent object under a new (generated) id.

Thanks in advance
Martin

max · **Posted:** Fri Jun 10, 2005 6:39 am

sorry yes - my bad. wrong usage of replicate.

Don't have any good solutions at hand then...

-max

kennedyk78 · **Joined:** Wed Mar 02, 2005 11:14 am **Posts:** 4

max,

Would be possible to generate the POJOs with Velocity that implement Cloneable?

If so has anybody written these templates as I'd love to get them too!

Otherwise I have to modify the POJOs by hand but they get over written when I generate the code and the code generated classes can't form part of my build.

Regards,
Kevin

hanson.char · **Joined:** Tue Jun 21, 2005 8:38 am **Posts:** 37

zdila wrote:

hi

I have the same problem and I can't solve it using replicate. BTW why to use replicate? Replicate is for making detached object persistent, isn't it?

Code:

Foo foo = session.get(Foo.class, fooId);
// here I'd like to read all properties of the lazy object (what method does that?)
session.evict(foo);
foo.setId(null);
session.save(foo);

this throws an exception:
...

Please provide a simple example how to clone a persistent object under a new (generated) id.

You many want to check out:
http://hansonchar.blogspot.com/2005/06/ ... rnate.html

Using beanlib, you can do something like:

Code:

Foo foo2 = HibernateBeanReplicator.dupEntityBean(foo);
foo2.setId(null);
session.save(foo2);

MarcF1 · **Posted:** Tue Jun 28, 2005 8:19 am

zdila wrote:

hi

I have the same problem and I can't solve it using replicate. BTW why to use replicate? Replicate is for making detached object persistent, isn't it?

Code:

Foo foo = session.get(Foo.class, fooId);
// here I'd like to read all properties of the lazy object (what method does that?)
session.evict(foo);
foo.setId(null);
session.save(foo);

Instead, if you do

Code:

session.update(foo);

the object should get saved with a new id. This is not really cloning though, the "same" object is saved to the database twice.

IvanLatysh · **Posted:** Mon Jul 04, 2005 12:38 pm

It is easy to do with org.apache.commons.beanutils

It looks something like that:

import static org.apache.commons.beanutils.PropertyUtils.*;

....
// retrieve an object
Foo persistedFoo = session.get(Foo.class, myFooId);
// create a new instance
Foo newFoo = new Foo();
// copy properties from persisted object to a new one
copyProperties(newFoo, persistedFoo);
...

antmarmo · **Joined:** Tue Jul 01, 2008 6:59 am **Posts:** 1

Hello

You can't use BeanUtils.copyproperties because the result is a reference (a new a pointer) to first object, so you have two references (or pointers) that are pointing to the same thing. This is a common issue of java language. If you change a property using a pointer, other pointer can see the changes of these property.

We need duplicate properties but the properties have to be new objects themselves: same content but diferent identity! (equals and hashcode issue)

Thanx!

msj4u · **Joined:** Wed Apr 25, 2007 11:44 pm **Posts:** 59

be advised do analyze that u need a deep copy or a shallow copy of the pojo/persistent object

Cameron McKenzie · **Posted:** Fri Jul 04, 2008 11:01 am

Indeed, make sure that when you do a session.replicate() , you are properly copying all associated proerties, including ones that might potentially be loaded in a Lazy fashion.