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Posted to ojb-user@db.apache.org by SE...@lohndirekt.de on 2003/12/16 11:39:57 UTC
Making all implementors of IF persistent
Hi,
I want to map a table to an interface.
I have some persistent classes and their according interfaces.
I also have some decorators wich add some aspects to the persistent classes
(e.g. change listening) and also implementing their respective interface.
Now I want to save the decorators directly instead of first unwrapping them.
Since all decorators are implementing the interface, ojb should know how to
save them.
The problem is that ojb doesn't know the decorator so it throws a
ClassNotPersistenceCapableException.
Do you have any ideas how to solve this?
Thanks in advance,
Sven
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Re: Making all implementors of IF persistent
Posted by Justis Peters <ju...@oculan.com>.
Hi Sven,
We have implemented this in our project here, and it works great. Check out the following tutorial:
http://db.apache.org/ojb/tutorial3.html
In particular, check out the sections titled "Extents and Polymorphism" and "Mapping Inheritance Hierarchies":
http://db.apache.org/ojb/tutorial3.html#Extents and Polymorphism
http://db.apache.org/ojb/tutorial3.html#Mapping Inheritance Hierarchies
We are using the mapping technique where each subclass has its own table, and OJB combines them together for you. I've had so much luck with this that we have begun using polymorphic references in most of our classes. Thus, many of my classes contain fields with a type as abstract as "Document", and there are 20 different classes that implement "Document". This has been great, because I can write special handlers in my webapp that can perform operations on any Document, regardless of which subclass it is.
Anyhow, enjoy!
Regards,
Justis Peters
Oculan Corp.
SEfftinge@lohndirekt.de [SEfftinge@lohndirekt.de] wrote:
> Hi,
> I want to map a table to an interface.
> I have some persistent classes and their according interfaces.
> I also have some decorators wich add some aspects to the persistent classes
> (e.g. change listening) and also implementing their respective interface.
> Now I want to save the decorators directly instead of first unwrapping them.
> Since all decorators are implementing the interface, ojb should know how to
> save them.
> The problem is that ojb doesn't know the decorator so it throws a
> ClassNotPersistenceCapableException.
>
> Do you have any ideas how to solve this?
>
> Thanks in advance,
> Sven
>
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> To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
> For additional commands, e-mail: ojb-user-help@db.apache.org
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To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
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Re: Making all implementors of IF persistent
Posted by Thomas Mahler <th...@web.de>.
Mhh, I guess you should add a class-descriptor for each Decorator class
into the reository.
then you have to define a class-descriptor for the IF and add extent
class definitions for all decorator classes.
Thomas
SEfftinge@lohndirekt.de wrote:
> Hi,
> I want to map a table to an interface.
> I have some persistent classes and their according interfaces.
> I also have some decorators wich add some aspects to the persistent classes
> (e.g. change listening) and also implementing their respective interface.
> Now I want to save the decorators directly instead of first unwrapping them.
> Since all decorators are implementing the interface, ojb should know how to
> save them.
> The problem is that ojb doesn't know the decorator so it throws a
> ClassNotPersistenceCapableException.
>
> Do you have any ideas how to solve this?
>
> Thanks in advance,
> Sven
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: ojb-user-unsubscribe@db.apache.org
> For additional commands, e-mail: ojb-user-help@db.apache.org
>
>
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