Aliasing/CustomConverter to add a field as attribute to another field

[René Brandenburger]

we have been using xstream happily for years, but now we reached a point, where we need to cut down on xml message sizes generated by xstream 1.4.20.

the actual xml generated looks something like this, with about 80 to 100 triplets (generated code)

<Person>

  <firstName>Jonathan</firstName>

  <firstNameHasBeenSet>true</firstNameHasBeenSet>

  <firstNameHasBeenChanged>false</firstNameHasBeenChanged>

  <lastName>Arbuckle</lastName>
  <lastNameHasBeenSet>true</lastNameHasBeenSet>
  <lastNameHasBeenChanged>false</lastNameHasBeenChanged>

  ...

  <fieldname>...</fieldname>

  <fieldnameHasBeenSet>...</fieldnameHasBeenSet>

  <fieldnameHasBeenChanged>...</fieldnameHasBeenChanged>

   ...

</Person>

what we intend to get is

<Person>

  <firstName set="true" changed="false">Jonathan</firstName>

  <lastName set="true" changed="false">Arbuckle</lastName>

  ...

  <fieldname set="..." changed="...">...</fieldname>

   ...

</Person>

i tried with aliasing and attribute aliasing, but i was only able to add the attributes to the Person tag.

Is there a way to achieve this by configuration or extending the existing reflection converters?

Regards

René

[Jörg Schaible]

Hi René

This is not possible for such a data structure as you might have assumed. You
have two options:

1/ Write a custom converter for Person that does what you want. See the
Converter tutorial, it is not too hard.

2/ Restructure your class to something like (assuming you don not access the
fields directly in your code):

class Person {
private StatefulField firstName;
private StatefulField lastName;
...
// getter / setters
}

or with a Map:

class Person {
private EnumMap<FieldName, StatefulField> fields;
// getter / setters
}

In both cases you can configure XStream to process the structure you're looking
for.

Regards,
Jörg

[René Brandenburger]

Hi Jörg,

thanks for the quick reply.

as 2/ is not an option (generated code) i will have a look into custom converters.

Regards

René

[Jörg Schaible]

On Monday, 21. August 2023, 13:34:22 CEST René Brandenburger wrote:
> Hi Jörg,
> thanks for the quick reply.
> as 2/ is not an option (generated code) i will have a look into custom
> converters.

Well, actually you can use reflection in your custom converter as well to
minimize the code to a great extend... ;-)

Regards,
Jörg