Dean wrote:
> This seems like a maintenance nightmare though. Every
> time someone
> regenerates new classes, he has to remember to go add
> the class and
> descriptor to the Resolver.
I agree.
Dean wrote this, too:
> I have no way of
> knowing if new ones appear, so I will have to diff the
> new with the old.
If new one unexpectedly appears, then
you probably won't have any code that uses the new unmarshalled class.
Dean also wrote:
> Maybe a subclass of ClassDescriptorResolverImpl should
> be generated for
> generated source code.
I like this idea; it will work well for app's that use a single schema file.
I'd like to hear Keith and Arnaud's $.02 on this.
There would be one small performance caveat -- Castor only needs you to invoke
_cdr.resolve()
for the top level classes. You'll get a touch of a performance hit
because the generator won't know which ones are the top level classes --
it will have to generate a _cdr.resolve() line for all classes or
rely on some implicit (read 'often forgotten') rule,
like "All global elements are top level classes".
If you have multiple schema files (like I do), this idea will require more work.
The generator will have to manage
the chaining of multiple subclasses of ClassDescriptorResolverImpl, one
for each schema file. You'll need some meta-data to keep the list of all these
subclasses.
> -----Original Message-----
> From: Dean Hiller [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, December 05, 2002 9:47 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [castor-dev] unmarshalling unkown xml with
> generated code
>
>
> I instead did the following but I am wondering if there
> is a cleaner
> solution. The ones I saw you write look like they
> require alot of
> maintenance too.
>
> _cdr = new ClassDescriptorResolverImpl();
> _cdr.associate(ButtonPress.class, new ButtonPressDescripto());
> _cdr.associate(Device.class, new DeviceDescriptor());
> .......25 more of these
> _cdr.associate(Something.class, new SomethingDescriptor());
>
> This seems like a maintenance nightmare though. Every
> time someone
> regenerates new classes, he has to remember to go add
> the class and
> descriptor to the Resolver. Is there a cleaner way?
>
> Maybe a subclass of ClassDescriptorResolverImpl should
> be generated for
> generated source code. If users have non-generated
> classes also, there
> could be a heirarchy of these resolvers just like
> ClassLoaders and
> ResourceBundles.
>
> Our plan is to keep to the CSTA schema standard, which
> means we will
> regenerate these classes and new ones might appear. I
> have no way of
> knowing if new ones appear, so I will have to diff the
> new with the old.
> Maybe I will write something to generate a
> ClasDescriptorResolver that
> auto adds all the generated classes and can have the
> normal Resolver as
> it's parent.
> I will have to think about this some more. If you have
> any ideas, let
> me know please,
> thanks for the suggestions below
> Dean
>
> [EMAIL PROTECTED] wrote:
>
> >You have a few options at this point.
> >First, be sure you've compiled the generated
> *Descriptor.java files
> >and they're in the cp.
> >
> >1)
> > _cdr = new ClassDescriptorResolverImpl();
> >
> > _cdr.resolve(/* one option for top level class */);
> > _cdr.resolve(/* a different option for top
> level class */);
> > _cdr.resolve(/* yet a third option for top
> level class */);
> >
> > _myUnmarshaller = new Unmarshaller((Class)null);
> > _myUnmarshaller.setResolver(_cdr);
> > //Now you can safely unmarshall.
> >
> >2) In the instance document, add an xsi:type attribute
> > on the node that you'll pass to the unmarshaller.
> > You don't need to specify it for the child nodes, b/c
> > this info is code generated into the
> *Descriptor.java files.
> > Here is an example:
> >
> ><?xml version="1.0" encoding="UTF-8"?>
> ><Wrapper>
> > <Aclass xsi:type="java:pollux.AxClass"
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";>
> > <sString>string23</sString>
> > <xInt>23</xInt>
> > </Aclass>
> ></Wrapper>
> >
> >
> >
> >3) Instead of using xsi:type, you can specify a namespace.
> > This option is nice because you can easily change
> > your package structure without breaking the client.
> >
> > See this post for an example:
> http://www.mail-archive.com/[email protected]/msg09658.html
> >
> >Hope this help,
> >
> >--Erik
> >
> > > -----Original Message-----
> > > From: Dean Hiller [mailto:[EMAIL PROTECTED]]
> > > Sent: Thursday, December 05, 2002 7:42 AM
> > > To: [EMAIL PROTECTED]
> > > Subject: Re: [castor-dev] unmarshalling unkown
> xml with
> > > generated code
> > >
> > >
> > > That didnt' seem to work, throws an exception saying
> > > "The class for the
> > > root element 'ButtonPress' could not be found from the
> > > UnmarshalHandler.
> > > I am looking at the UnmarshalHandler and the
> classDesc
> > > returned from
> > > _cdResolver.resolveByXMLName(name, namespace,
> null); is
> > > null. Because
> > > of this, the exception is thrown. _cdResolver is a
> > > ClassDescriptorResolverImpl, so I am now looking at
> > > that. It loads from
> > > the mapping first(which I don't have as I read this is
> > > for non-generated
> > > source code). It then goes through the cached
> > > elements. The cache size
> > > is 0. There are no elements in the cache. Am I
> > > missing something?
> > > thanks very much for your help,
> > > Dean
> > >
> > > [EMAIL PROTECTED] wrote:
> > >
> > > >Use this:
> > > >
> > > > _myUnmarshaller = new
> Unmarshaller((Class)null);
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Dean Hiller [mailto:[EMAIL PROTECTED]]
> > > > > Sent: Wednesday, December 04, 2002 3:56 PM
> > > > > To: [EMAIL PROTECTED]
> > > > > Subject: [castor-dev] unmarshalling
> unkown xml with
> > > > > generated code
> > > > >
> > > > >
> > > > > I am sorry, the mail archives seem to
> be down, so I
> > > > > could not search
> > > > > them yet.
> > > > >
> > > > > I see Mapping is supposed to be used
> for non-generated
> > > > > code from what I
> > > > > read so far. How do I unmarshal
> objects where I don't
> > > > > know what the xml
> > > > > is ahead of time. I can't seem to
> just do this
> > > > >
> > > > > UnMarshaller u = new UnMarshaller();
> > > > > Object o = u.unmarshal(myStream);
> > > > > if(o instanceof Device).......
> > > > > else if(o instanceof System).....
> > > > >
> > > > > I am sure castor can handle this. I
> am just not sure
> > > > > how to do it.
> > > > > thanks for any help in this,
> > > > > Dean
> > > > >
> > > > >
> > >
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