Question about inheritance...

[Ben Douglas]

Hello,

Does anyone have a sample of using xstream in inherited classes using 
converters?  Essentially I have an object that's inherited through about 
5 other classes, I'd like to put the correct converters in the correct 
class, so the end class may only have one, even though there may be 10 
total converters.

Sample:

Class A {
    String foobar;

    public Object clone() {
         // use xstream converter on variable foobar
    }

}

Class B extends A {
    String helloworld;

    public Object clone() {
         // use xstream converter on variable helloworld
         // but also call a super.clone() or something so the converter
         // on foobar is also called
    }

}

[Jörg Schaible-2]

Hi Ben,

Ben Douglas wrote:

> Hello,
>
> Does anyone have a sample of using xstream in inherited classes using
> converters?  Essentially I have an object that's inherited through about
> 5 other classes, I'd like to put the correct converters in the correct
> class, so the end class may only have one, even though there may be 10
> total converters.
>
> Sample:
>
> Class A {
>      String foobar;
>
>      public Object clone() {
>           // use xstream converter on variable foobar
>      }
>
> }
>
> Class B extends A {
>      String helloworld;
>
>      public Object clone() {
>           // use xstream converter on variable helloworld
>           // but also call a super.clone() or something so the converter
>           // on foobar is also called
>      }
>
> }

If you use XStream for cloning, why do you create any custom converter at
all?

- Jörg


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[Ben Douglas]

Hi Jörg,

I have some singleton objects that the objects I'm cloning point to.  In
order to save time / risk duplicate singletons, I just write a string to
the xml instead of the entire object (some are rather large).  So class
A may have singleton Singleton_1 and class B may have Singleton_2.  I
can put the converter for both in B, but thought it would make sense to
put singleton_1 in A, and singleton_2 in b.  I just used Strings as a
more basic example.

Thanks,
Ben

On 10/29/2009 11:00 AM, Jörg Schaible wrote:

> Hi Ben,
>
> Ben Douglas wrote:
>
>    
>> Hello,
>>
>> Does anyone have a sample of using xstream in inherited classes using
>> converters?  Essentially I have an object that's inherited through about
>> 5 other classes, I'd like to put the correct converters in the correct
>> class, so the end class may only have one, even though there may be 10
>> total converters.
>>
>> Sample:
>>
>> Class A {
>>       String foobar;
>>
>>       public Object clone() {
>>            // use xstream converter on variable foobar
>>       }
>>
>> }
>>
>> Class B extends A {
>>       String helloworld;
>>
>>       public Object clone() {
>>            // use xstream converter on variable helloworld
>>            // but also call a super.clone() or something so the converter
>>            // on foobar is also called
>>       }
>>
>> }
>>      
> If you use XStream for cloning, why do you create any custom converter at
> all?
>
> - Jörg
>
>
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>
>
>    

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[Jörg Schaible-2]

Hi Ben,

Ben Douglas wrote:

> Hi Jörg,
>
> I have some singleton objects that the objects I'm cloning point to.  In
> order to save time / risk duplicate singletons, I just write a string to
> the xml instead of the entire object (some are rather large).  So class
> A may have singleton Singleton_1 and class B may have Singleton_2.  I
> can put the converter for both in B, but thought it would make sense to
> put singleton_1 in A, and singleton_2 in b.  I just used Strings as a
> more basic example.

Why don't you simply write a converter for the singleton's type (even if the
individual instances are different types of a class hierarchy)? If you can
represent it by a String that can be used to refer the proper singleton at
deserialization time, it's all you need (and the proper condition in the
canConvert method).


- Jörg


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[Ben Douglas]

Yes -- I actually have converters for the singletons I need.  The
question is if I have class A that uses singleton 1, and class B that
uses singleton 2, and class A inherits class B, I'd like class B to take
care of the singleton 2 converter (since the writer of A may not even
use singleton 2 that class B uses).  So really it'd be great to be able
to write a "clone" for A and B -- each of which takes care of any
converters they need.  So A would only do a converter for '1', but
inherit the use of the converter for singleton '2'.  Let me know if a
better example would work.

Thanks,
Ben

On 11/03/2009 06:49 PM, Jörg Schaible wrote:

> Hi Ben,
>
> Ben Douglas wrote:
>
>    
>> Hi Jörg,
>>
>> I have some singleton objects that the objects I'm cloning point to.  In
>> order to save time / risk duplicate singletons, I just write a string to
>> the xml instead of the entire object (some are rather large).  So class
>> A may have singleton Singleton_1 and class B may have Singleton_2.  I
>> can put the converter for both in B, but thought it would make sense to
>> put singleton_1 in A, and singleton_2 in b.  I just used Strings as a
>> more basic example.
>>      
> Why don't you simply write a converter for the singleton's type (even if the
> individual instances are different types of a class hierarchy)? If you can
> represent it by a String that can be used to refer the proper singleton at
> deserialization time, it's all you need (and the proper condition in the
> canConvert method).
>
>
> - Jörg
>
>
> ---------------------------------------------------------------------
> To unsubscribe from this list, please visit:
>
>      http://xircles.codehaus.org/manage_email
>
>
>
>    

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[Jörg Schaible-2]

Hi Ben,

Ben Douglas wrote:

> Yes -- I actually have converters for the singletons I need.  The
> question is if I have class A that uses singleton 1, and class B that
> uses singleton 2, and class A inherits class B, I'd like class B to take
> care of the singleton 2 converter (since the writer of A may not even
> use singleton 2 that class B uses).  So really it'd be great to be able
> to write a "clone" for A and B -- each of which takes care of any
> converters they need.  So A would only do a converter for '1', but
> inherit the use of the converter for singleton '2'.

Even with the example in your first posting I am still not understanding
what you really try to do, sorry.

> Let me know if a
> better example would work.

Definitely.

- Jörg


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