Why doesn't OjbectConverter getObject call this.newInstance method ?

[Dan Connelly <ds...@adelphia.net>]

All:

I do a pm.save on the root of my model objects.   Then I want to fetch 
the object model back using some code like:

    RootClass root = (RootClass) pm.getObject("/test.root");

This fails because my model uses a factory class, not constructors, to 
instantiate model objects, including instances of the RootClass.

This pm is constructed using my custom MyObjectConverterImpl, which is a 
subclass of ObjectConverterImpl.   I expected that this would give me a 
way to control object creation.    It seems that I was wrong (unless I 
copy major portions of ObjectConverterImpl).

ObjectConverterImpl, if I delegate getObject to it, attempts to get a 
root object using this code:

       Object root = 
ReflectionUtils.newInstance(classDescriptor.getClassName());

That causes the failure.   ReflectionUtils is out of my control.   
ObjectConverterImpl does not invoke *this.newInstance* so that 
MyObjectConverterImpl can get control back for the construction in my 
objects (using my factory class).

What are the plans, if any, are there to accommodate object models which 
use a factory class for construction of its objects?

       -- Dan

Re: Why doesn't OjbectConverter getObject call this.newInstance method ?

[Christophe Lombart <ch...@gmail.com>]

Thanks - I will review it when it will be in Jira.

br
Christophe


On 9/13/06, Dan Connelly <ds...@adelphia.net> wrote:
> All:
>
> I implemented a simple change in ObjectConverterImpl.   It solves the
> problem I reported.
>
> I added the following method:
>
>     protected Object newInstance(String className) {
>         return ReflectionUtils.newInstance(className);
>     }
>
>
> Elsewhere in ObjectConverterImpl, it will now invoke
>
>             this.newInstance(classDescriptor.getClassName());
>
> where previously the invocation had been
>
>             ReflectionUtils.newInstance(classDescriptor.getClassName());
>
> Now I can over-ride the newInstance in MyObjectConverterImpl (which
> subclasses ObjectConverterImpl).   This allows me to construct objects
> for my model using its factory class.
>
> I will submit an enhancement Jira tomorrow to get this change into
> ObjectConvertImpl.
>
>          -- Dan
>
>
>
>
>
>
> Dan Connelly wrote:
>
> > All:
> >
> > I do a pm.save on the root of my model objects.   Then I want to fetch
> > the object model back using some code like:
> >
> >    RootClass root = (RootClass) pm.getObject("/test.root");
> >
> > This fails because my model uses a factory class, not constructors, to
> > instantiate model objects, including instances of the RootClass.
> >
> > This pm is constructed using my custom MyObjectConverterImpl, which is
> > a subclass of ObjectConverterImpl.   I expected that this would give
> > me a way to control object creation.    It seems that I was wrong
> > (unless I copy major portions of ObjectConverterImpl).
> >
> > ObjectConverterImpl, if I delegate getObject to it, attempts to get a
> > root object using this code:
> >
> >       Object root =
> > ReflectionUtils.newInstance(classDescriptor.getClassName());
> >
> > That causes the failure.   ReflectionUtils is out of my control.
> > ObjectConverterImpl does not invoke *this.newInstance* so that
> > MyObjectConverterImpl can get control back for the construction in my
> > objects (using my factory class).
> >
> > What are the plans, if any, are there to accommodate object models
> > which use a factory class for construction of its objects?
> >
> >       -- Dan
> >
> >
> >
> >
>
>


-- 
Best regards,

Christophe

Re: Why doesn't OjbectConverter getObject call this.newInstance method ?

[Dan Connelly <ds...@adelphia.net>]

All:

I implemented a simple change in ObjectConverterImpl.   It solves the 
problem I reported.

I added the following method:

    protected Object newInstance(String className) {
        return ReflectionUtils.newInstance(className);
    }


Elsewhere in ObjectConverterImpl, it will now invoke

            this.newInstance(classDescriptor.getClassName());

where previously the invocation had been

            ReflectionUtils.newInstance(classDescriptor.getClassName());

Now I can over-ride the newInstance in MyObjectConverterImpl (which 
subclasses ObjectConverterImpl).   This allows me to construct objects 
for my model using its factory class.

I will submit an enhancement Jira tomorrow to get this change into 
ObjectConvertImpl.

         -- Dan






Dan Connelly wrote:

> All:
>
> I do a pm.save on the root of my model objects.   Then I want to fetch 
> the object model back using some code like:
>
>    RootClass root = (RootClass) pm.getObject("/test.root");
>
> This fails because my model uses a factory class, not constructors, to 
> instantiate model objects, including instances of the RootClass.
>
> This pm is constructed using my custom MyObjectConverterImpl, which is 
> a subclass of ObjectConverterImpl.   I expected that this would give 
> me a way to control object creation.    It seems that I was wrong 
> (unless I copy major portions of ObjectConverterImpl).
>
> ObjectConverterImpl, if I delegate getObject to it, attempts to get a 
> root object using this code:
>
>       Object root = 
> ReflectionUtils.newInstance(classDescriptor.getClassName());
>
> That causes the failure.   ReflectionUtils is out of my control.   
> ObjectConverterImpl does not invoke *this.newInstance* so that 
> MyObjectConverterImpl can get control back for the construction in my 
> objects (using my factory class).
>
> What are the plans, if any, are there to accommodate object models 
> which use a factory class for construction of its objects?
>
>       -- Dan
>
>
>
>