Attribut change listener

[Klesk <cg...@hotmail.com>]

Hi,

Is there a way to implements an attribute listener ?
My goal is to be notified when an attribute content changed (getting
attribute name, old and new value).
Is is feasible ?


Regards,



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RE: Attribut change listener

[Boblitz John <jo...@bertschi.com>]

In that case, why not just implement notification in the setter for the attribute?

public void setSomeAttribute(Object someNewValue) {
	Object oldValue = attributeValue;
	attibuteValue = someNewValue;
	System.out.println("changed: " + oldValue + " -> " attributeValue);
}

John


> -----Original Message-----
> From: Klesk [mailto:cg85@hotmail.com]
> Sent: Dienstag, 4. Juli 2017 12:11
> To: users@openjpa.apache.org
> Subject: RE: Attribut change listener
> 
> Hello,
> 
> In fact, I need to be notified when an attribute content change ASAP.
> Methods with an event annotation are called when the EntityManager is
> called. That's mhy I don't use annotations ;)
> 
> Regards,
> 
> 
> 
> --
> View this message in context:
> http://openjpa.208410.n2.nabble.com/Attribut-change-listener-
> tp7590226p7590229.html
> Sent from the OpenJPA Users mailing list archive at Nabble.com.

RE: Attribut change listener

[Klesk <cg...@hotmail.com>]

Hello,

In fact, I need to be notified when an attribute content change ASAP.
Methods with an event annotation are called when the EntityManager is
called. That's mhy I don't use annotations ;)

Regards,



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RE: Attribut change listener

[Boblitz John <jo...@bertschi.com>]

Hello,

You can create a method and annotate it with    @PostPersist  @PostUpdate  @PostRemove (also pre) depending on your needs.

Then access the old and new states of the entity with

PersistenceCapable pcCurrentState = (PersistenceCapable) pCurrentState;
StateManagerImpl sm = (StateManagerImpl) pcCurrentState.pcGetStateManager();
PCState state = sm.getPCState();
SaveFieldManager sfm = sm.getSaveFieldManager();
PersistenceCapable pcOldState = sfm.getState();

You then cast the states to your entity

                oldState = (Entity) pcOldState;
                newState = (Entity) pcCurrentState;

I do believe you need to add something to your persistence.xml to allow this to work, but I don't recall for certain.



Hope this helps

John

> -----Original Message-----
> From: Klesk [mailto:cg85@hotmail.com]
> Sent: Dienstag, 4. Juli 2017 11:14
> To: users@openjpa.apache.org
> Subject: Re: Attribut change listener
> 
> My workaround (needs to be deeply tested):
> 
> 
> Klesk wrote
> >     @Test
> >     public void testProxy() throws Exception {
> >         final EntityManager em = factory.createEntityManager();
> >         final SUti entity = em.find(SUti.class, 1);
> >
> >         final ProxyFactory proxiter = new ProxyFactory();
> >         proxiter.setSuperclass(entity.getClass());
> >         proxiter.setHandler((instance, method, wrapper, args) -> {
> >             instance = entity;
> >             wrapper = entity.getClass().getMethod(method.getName(),
> > method.getParameterTypes());
> >             if(method.getName().startsWith("set")) {
> >                 final String methodName = method.getName();
> >                 final Object previous =
> > instance.getClass().getMethod("get" +
> > methodName.substring(3)).invoke(instance);
> >                 System.out.println("changed: " + previous + " -> " +
> > args[0]);
> >             }
> >             return wrapper.invoke(instance, args);
> >         });
> >
> >         final SUti mock = (SUti) proxiter.create(new Class[0], new
> > Object[0]);
> >         assertEquals("AAAA", entity.getUtLibuti());
> >         assertEquals("AAAA", mock.getUtLibuti());
> >         mock.setUtLibuti("test");
> >         assertEquals("test", entity.getUtLibuti());
> >         assertEquals("test", mock.getUtLibuti());
> >     }
> 
> 
> 
> 
> 
> --
> View this message in context:
> http://openjpa.208410.n2.nabble.com/Attribut-change-listener-
> tp7590226p7590227.html
> Sent from the OpenJPA Users mailing list archive at Nabble.com.

Re: Attribut change listener

[Klesk <cg...@hotmail.com>]

My workaround (needs to be deeply tested):


Klesk wrote
>     @Test
>     public void testProxy() throws Exception {
>         final EntityManager em = factory.createEntityManager();
>         final SUti entity = em.find(SUti.class, 1);
> 
>         final ProxyFactory proxiter = new ProxyFactory();
>         proxiter.setSuperclass(entity.getClass());
>         proxiter.setHandler((instance, method, wrapper, args) -> {
>             instance = entity;
>             wrapper = entity.getClass().getMethod(method.getName(),
> method.getParameterTypes());
>             if(method.getName().startsWith("set")) {
>                 final String methodName = method.getName();
>                 final Object previous =
> instance.getClass().getMethod("get" +
> methodName.substring(3)).invoke(instance);
>                 System.out.println("changed: " + previous + " -> " +
> args[0]);
>             }
>             return wrapper.invoke(instance, args);
>         });
> 
>         final SUti mock = (SUti) proxiter.create(new Class[0], new
> Object[0]);
>         assertEquals("AAAA", entity.getUtLibuti());
>         assertEquals("AAAA", mock.getUtLibuti());
>         mock.setUtLibuti("test");
>         assertEquals("test", entity.getUtLibuti());
>         assertEquals("test", mock.getUtLibuti());
>     }





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