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Posted to ojb-user@db.apache.org by St...@zas.admin.ch on 2004/07/08 15:57:05 UTC
Réf. : Re: Mixing OJB objects with non-OJB objects
Thank you for the quick answer. I defined a custom RowReader and it works
almost exactly like I want to.
I would be fully happy if I could cache the object in the
PersistenceBroker's cache. Is there a way to get a reference to the cache
from the RowReader ?
Stefano
|---------+--------------------------->
| | Thomas Dudziak |
| | <tomdz@first.fhg|
| | .de> |
| | |
| | 08.07.2004 09:34|
| | Veuillez |
| | répondre à "OJB |
| | Users List" |
| | |
|---------+--------------------------->
>----------------------------------------------------------------------------------------------------------------------|
| |
| Pour : OJB Users List <oj...@db.apache.org> |
| cc : |
| Objet : Re: Mixing OJB objects with non-OJB objects |
>----------------------------------------------------------------------------------------------------------------------|
Stefano.Juri@zas.admin.ch wrote:
> Hello,
>
> I have two types of persistent objects in my application : objects that
are
> stored in a RDB and objects that are managed from an other application
(for
> instance, in my environment persons and adresses are managed in a legacy
> application developed in Natural/Adabas). The objects of the second type
> are considered as read-only, I don'need to store them back after the
> processing. The objects of both types are mixed in the business model,
the
> business layer of the application does not need to bother where the data
is
> stored.
>
> Example : I have a class Car with has an Owner. Car is stored in my RDB
and
> the table contains the identifier of the owner. Owner is stored in the
> external application. When OJB instantiates aCar it should also
instantiate
> it's Owner.
>
> I tried with the factory-class, but since the factory-method does not
> accept parameters, I don't know how to pass the identifier of the owner
and
> I need that information to call the external application's API. Is there
a
> way to get access to the db-row from the factory-method ? If no, is there
a
> smarter way to do the job ?
Dependiding on whether you want to map the Owner's identifier to a field
of Car, you can use initialization-method (class descriptor) which is
called after OJB has read the object from the database (if I'm not
mistaken), or you can use a custom row-reader implementation to fetch
the additional row from the db:
http://db.apache.org/ojb/docu/guides/advanced-technique.html#Using+Rowreader
Tom
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Re: Mixing OJB objects with non-OJB objects
Posted by Thomas Dudziak <to...@first.fhg.de>.
Stefano.Juri@zas.admin.ch wrote:
>Thank you for the quick answer. I defined a custom RowReader and it works
>almost exactly like I want to.
>
>I would be fully happy if I could cache the object in the
>PersistenceBroker's cache. Is there a way to get a reference to the cache
>from the RowReader ?
>
>
You can get the currently used cache from a PersistenceBroker via the
serviceObjectCache() method.
Tom
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