XStream, Aliasing and "DuplicateFieldException"

Question

I'm trying to write an app so that it is able to read this kind of XML and create an entire object based on it;

<actor id="id273211" PGFVersion="0.19" GSCVersion="0.10.4">
  <attributes>
    <text id="name">Actor 1b</text>
    <point id="position">
      <real id="x">0</real>
      <real id="y">0</real>
    </point>
  </attributes>
</actor>

My problem is I'm aliasing members of the class Point as "real" and it gives an exception.

What I have now is;

@XStreamAlias("actor")
public class Actor {

    @XStreamAsAttribute
    String id = "",PGFVersion = "", GSCVersion = "";
    Attributes attributes = new Attributes();
}


public class Attributes {

    public Text text = new Text("name", "Actor 1");
    public Point point = new Point();

}


@XStreamConverter(value=ToAttributedValueConverter.class, strings={"value"})
@XStreamAlias("text")
public class Text {

    @XStreamAsAttribute
    String id;

    String value;

    public Text(String text, String value) {
        this.id = text;
        this.value = value;
    }


public class Point {
     @XStreamAlias("real")
     public Real x = new Real("x", "11");
     @XStreamAlias("real") 
     public Real y = new Real("y", "21");
     @XStreamAsAttribute
     public String id = "position";

}

And my Test.java:

public static void main(String[] args) throws Exception {

    XStream xstream = new XStream();

    Actor actor2 = new Actor();

    xstream.processAnnotations(Text.class);
    xstream.processAnnotations(Real.class);
    xstream.processAnnotations(Point.class);
    xstream.processAnnotations(Actor.class);

    String xml = xstream.toXML(actor2);

    System.out.println(xml);

}

This outputs XML perfectly, as follows:

<actor id="" PGFVersion="" GSCVersion="">
  <attributes>
    <text id="name">Actor 1</text>
    <point id="position">
      <real id="x">11</real>
      <real id="y">21</real>
    </point>
  </attributes>
</actor>

But when I try to import it using:

String xml = xstream.toXML(actor2);

Actor actorNew = (Actor)xstream.fromXML(xml);
System.out.println(xml);

It gives an exception:

Exception in thread "main" com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter$DuplicateFieldException: Duplicate field y ---- Debugging information ---- field : y class : projectmerger1.Point required-type : projectmerger1.Point converter-type : com.thoughtworks.xstream.converters.reflection.ReflectionConverter path : /projectmerger1.Actor/attributes/point/real[2] line number : 6 class[1] : projectmerger1.Attributes class[2] : projectmerger1.Actor

version : 1.4.6

Is this a wrong setup as a whole or can I continue using it with some tweaks?

Answer 1

I solved it by changing in Point class;

public class Point {
    /*
     @XStreamAlias("real")
     @XStreamAlias("real2") 
     public Real y = new Real("y", "21");
     @XStreamAsAttribute
     public String id = "position";
     */

    @XStreamImplicit
     public List xy = new ArrayList();


     public void add(Real entry) {
                xy.add(entry);
        }

}

and adding this to my Test.java:

    actor2.attributes.point.add(new Real("x","0"));
    actor2.attributes.point.add(new Real("y","0"));

I'll keep experimenting with this. Thanks for the support.