JAXB Marshalling and Generics

Question

I am trying to use JAXB\'s introspection to marshall and unmashall some existing domain objects marked up with JAXB annotations. Most things work as expected, but I am havin

Answer 1

You could write a custom adapter (not using JAXB's XmlAdapter) by doing the following:

1) declare a class which accepts all kinds of elements and has JAXB annotations and handles them as you wish (in my example I convert everything to String)

@YourJAXBAnnotationsGoHere
public class MyAdapter{

  @XmlElement // or @XmlAttribute if you wish
  private String content;

  public MyAdapter(Object input){
    if(input instanceof String){
      content = (String)input;
    }else if(input instanceof YourFavoriteClass){
      content = ((YourFavoriteClass)input).convertSomehowToString();
    }else if(input instanceof .....){
      content = ((.....)input).convertSomehowToString();
    // and so on
    }else{
      content = input.toString();
    }
  }
}

// I would suggest to use a Map,IMyObjToStringConverter> ...
// to avoid nasty if-else-instanceof things

2) use this class instead of E in your to-be-marshalled class

NOTES

• Of course this would not work for complex (nested) data structures.
• You have to think how to unmarshall this back again, could be more tricky. If it's too tricky, wait for a better proposal than mine ;)