Thats mighty fair. I expect to do this for 20 or so classes, so I
might not bother writing descriptors.
Thanks.
Rick
-----Original Message-----
From: Keith Visco [mailto:[EMAIL PROTECTED]
Sent: Thursday, July 15, 2004 12:57 PM
To: [EMAIL PROTECTED]
Subject: Re: [castor-user] [XML] Inheritance and mapping the base class.
Hi Rick,
One workaround, which you could probably implement today, is to write
the ClassDescriptor for your sub classes:
So in this case, if you have a com.acme.Something class , that extends
com.acme.Base class, you can write a com.acme.SomethingDescriptor class
which extends XMLClassDescriptorImpl and returns com.acme.Base.class:
package com.acme;
public class SomethingDescriptor extends XMLClassDescriptorImpl {
...
/**
*
* @return Class
*/
public java.lang.Class getJavaClass()
{
return com.acme.Base.class;
} //-- java.lang.Class getJavaClass()
...
}
It's a bit of work to write a Descriptor by hand, but it should work.
Usually if I have to write a descriptor by hand, I use an XML Schema and
have Castor generate me a descriptor fairly close to what I'm trying to
write and then I tweak it.
As for writing the enhancement, it won't come right away, as I have some
prior commitments on a few bugs (right Jeremy? :-) that I need to fix
before I even have a chance to look into this further.
--Keith
Rick Ross wrote:
>
> That would be magnificent!
>
> Believe me, I'm very happy with the way Castor handles things by
> default. I just ran into a situation where there was no easy way to
> marshall what I need to.
>
> So.. Tomorrow? :-)
>
> Rick
>
> -----Original Message-----
> From: Keith Visco [mailto:[EMAIL PROTECTED]
> Sent: Thursday, July 15, 2004 10:38 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [castor-user] [XML] Inheritance and mapping the base
> class.
>
> Hi Rick,
>
> It sounds like we need a new feature in the mapping file, something
> like:
>
> <class name="Something" extends="com.acme.MyBase">
> <bind-xml marshalAs="com.acme.MyBase"/>
>
> ...
> </class>
>
> The reason Castor marshals as Something, rather than MyBase today is
> that it tries as hard as it can to preserve what is being marshalled,
> so that when you unmarshal you get back an object model similar to
> that which you started with.
>
> Also, many base classes are abstract, so saving the concrete class
> helps to prevent unmarshal errors in the future.
>
> Based on what you're trying to do, it seems like we simply need a way
> for one to say a particular class should be "handled" as a instance of
> one of it's base class (or an ancestor class) or interfaces. In a
> sense, a "virtual" cast.
>
> --Keith
>
> Rick Ross wrote:
> >
> > That's correct, except that I would be perfectly happy (ecstatic
> > really) to have the class attribute be set to the base class name as
> > well.
> >
> > R
> >
> > -----Original Message-----
> > From: Jay Goldman [mailto:[EMAIL PROTECTED]
> > Sent: Thursday, July 15, 2004 7:54 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: [castor-user] [XML] Inheritance and mapping the base
> > class.
> >
> > Using transient and/or setting the auto-complete will eliminate any
> > unwanted properties; however, won't the top level element still be
> > 'something' or 'some-other-thing'?. I understood Rick's question as
> > wanting a way to marshall a 'Something' and get xml that has a top
> > level element of 'base' without a 'class' attribute. Jay
> >
> > -----Original Message-----
> > From: Benoit Maisonny [mailto:[EMAIL PROTECTED]
> > Sent: Wednesday, July 14, 2004 3:23 PM
> > To: [EMAIL PROTECTED]
> > Subject: Re: [castor-user] [XML] Inheritance and mapping the base
> > class.
> >
> > You can tell Castor to marshall only what you want from your
> > classes. One way is by setting the transient attribute to true on
> > the field element in your mapping. Another way is by setting the
> > auto-complete attribute to false on the class element and specifying
> > each field that
>
> > you want to marshall. I guess you can do it in yet another way using
> > FieldHandlers. Read the documentation to decide what's best for you.
> >
> > Benoit
> >
> > Rick Ross wrote:
> >
> > > Sure, I recognize that java is behaving as expected. But surely
> > > this is not the first time this has come up.
> > >
> > > I would have imagined many people want to do this, and for us,
> > > we'd rather avoid clone/copy because we expect to do it a lot.
> > >
> > > Thanks.
> > >
> > > R
> > >
> > > -----Original Message----- From: Jay Goldman
> > > [mailto:[EMAIL PROTECTED] Sent: Wednesday, July 14, 2004 5:46
> > > AM
> > > To: [EMAIL PROTECTED] Subject: Re: [castor-user] [XML]
> > > Inheritance and mapping the base class.
> > >
> > >
> > > Since java objects (unlike c++ objects) do not change their type
> > > when
> >
> > > they are 'cast' the castor behavior is correct. In fact, the cast
> > > is
>
> > > essentially meaningless - at runtime you have a Something or a
> > > SomeOtherThing not simply a Base. You could obviously create a
> > > Base instance using the object you have (via clone or copy
> > > constructor on
> > > Base) and then marshall this instance.
> > >
> > > Jay
> > >
> > > -----Original Message----- From: Rick Ross
> > > [mailto:[EMAIL PROTECTED]
> >
> > > Sent: Wednesday, July 14, 2004 1:11 AM
> > > To: [EMAIL PROTECTED] Subject: [castor-user] [XML]
> > > Inheritance and mapping the base class.
> > >
> > >
> > >
> > > Hi. I have some base classes I use for a group of classes.
> > > Something
> > > like:
> > >
> > > public class Base { // a bunch of bean style getters and setters.
> > > }
> > >
> > > public class Something extends Base { // different getters and
> > > setters
> >
> > > }
> > >
> > > public class SomeOtherThing extends Base { // you get the
> > > picture...
>
> > > }
> > >
> > > When objects are instantiated, they are always instantiated as
> > > Something or SomeOtherThing objects. When I go to marshall them,
> > > I always cast them into Base objects because that is all I want
> > > marshalled. However, I always get the fields from Something and
> > > SomeOtherThing.
> > >
> > > In fact, in the xml output, the class attribute is always the
> > > fully qualified class name of the instantiated class, not the base
> > > class.
> > >
> > > I have tried a mapping and using the "extends" attribute, but that
> > > did
> >
> > > not work either. In that case, the output had something like
> > > some-other-thing as the class name, which I seem to recall is a
> > > castor
> >
> > > name mangling convention.
> > >
> > > I thought I could do this in the mapping :
> > >
> > > <class name="SomeOtherThing" extends="Base" /> <class name="Base">
> > > ... all of my mapping for the base class fields here. </class>
> > >
> > > Can anyone offer a bit of insight? Am I just missing the concept
> or
> > > missing a setting?
> > >
> > > Thanks
> > >
> > > Rick
> > >
> > >
> > >
> > >
> > > ------------------------------------------------------------------
> > > --
> > > --
> > > --
> > >
> > >
> > > ----------------------------------------------------------- If you
> > > wish to unsubscribe from this mailing, send mail to
> > > [EMAIL PROTECTED] with a subject of: unsubscribe castor-user
> > >
> > >
> >
> > -----------------------------------------------------------
> > If you wish to unsubscribe from this mailing, send mail to
> > [EMAIL PROTECTED] with a subject of:
> > unsubscribe castor-user
> >
> > -----------------------------------------------------------
> > If you wish to unsubscribe from this mailing, send mail to
> > [EMAIL PROTECTED] with a subject of:
> > unsubscribe castor-user
> >
> >
> >
> ----------------------------------------------------------------------
> --
> > -----------------------------------------------------------
> > If you wish to unsubscribe from this mailing, send mail to
> > [EMAIL PROTECTED] with a subject of:
> > unsubscribe castor-user
>
> -----------------------------------------------------------
> If you wish to unsubscribe from this mailing, send mail to
> [EMAIL PROTECTED] with a subject of:
> unsubscribe castor-user
>
>
>
------------------------------------------------------------------------
> -----------------------------------------------------------
> If you wish to unsubscribe from this mailing, send mail to
> [EMAIL PROTECTED] with a subject of:
> unsubscribe castor-user
-----------------------------------------------------------
If you wish to unsubscribe from this mailing, send mail to
[EMAIL PROTECTED] with a subject of:
unsubscribe castor-user
-----------------------------------------------------------
If you wish to unsubscribe from this mailing, send mail to
[EMAIL PROTECTED] with a subject of:
unsubscribe castor-user
