Strange behaviour of: --session.get(class,id)

HibRookie · **Joined:** Mon Mar 26, 2007 4:22 am **Posts:** 4

Hibernate version: 3.2

Hallo,

I asked this question before, but unfortunately nobody could provide me any hint on this. I think this is an error, since Hibernate shows different behaviour depending on 2nd-level-cache on or off.

Any help would be greatly appreciated!
Andreas
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I have the following mapping file:

Code:

<hibernate-mapping package="com.demo.pojos">
   <class name="com.demo.pojos.Produkt"
      dynamic-update="true">

      <cache usage="read-only" region="ProduktCache"/>

      <id name="id">
         <column name="ID_TXT" sql-type="CHAR(16)" />
      </id>

        <... several properties ...>


      <union-subclass
         name="com.demo.pojos.ElementarProdukt"
         table="QD01V171">
            <... several properties ...>
      </union-subclass>

      <union-subclass
         name="com.demo.pojos.KombiProdukt"
         table="QD01V151">
            <... several properties ...>
      </union-subclass>

   </class>
</hibernate-mapping>

When I'm not using EHCache the following code runs as expected:

Code:

   IPojo kpPojo = session.get( KombiProdukt.class, produktId );
   IPojo epPojo = session.get( ElementarProdukt.class, produktId );

   if ( kpPojo != null ) {
        // do something with KombiProdukt

   } else if ( epPojo != null ) {
        // do something with ElementarProdukt

   }

(I know this is not very clever code from OO-Perspective but I'm porting an existing project and dont want to change more than necessary).

So when my ID (which is unique across all tables) finds a KombiProdukt or an ElementarProdukt, everything works fine.

BUT:
When I activate EHCache (without changing anything else) it occurs, that sometimes an object of type ElementarProdukt is found by
session.get( KombiProdukt.class, produktId )

In my understanding, the class-Argument in get(Class,Serializable) should prevent exactly this, shouldn't it?

The Onlinehelp says:
"Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. (If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance.) "

It would be great if someone could explain this to me.
Thanks in advance.

rahul dongre · **Posted:** Mon Jun 04, 2007 5:41 pm

Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. (If the instance, or a proxy for the instance, is already associated with the session, return that instance or proxy.

As javadocs about the session.get() method says above.

So if your cache is enable and you try to get the data from the session.get() method with the specific id and id persists in the session. Will hit the cache first and return the same.