Description Blaise Doughan 2010-12-16 09:19:13 EST

The following example throws an error that ClassA does not have a no-arg constructor.  Since ClassA is abstract it doesn't need one.

import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.adapters.XmlAdapter;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

public class JaxbTest {

    public static abstract class ClassA {
        public ClassA(String id) {
        }
    }

    @XmlRootElement
    @XmlJavaTypeAdapter(MyAdapter.class) // does not have an effect
    public static class ClassB extends ClassA {

        public String text;

        public ClassB() {
            super("");
        }
    }

    public static class ValB {
        public String text;
    }

    public static class MyAdapter extends XmlAdapter<ValB, ClassB> {

        @Override
        public ClassB unmarshal(ValB v) throws Exception {
            ClassB b = new ClassB();
            b.text = v.text;
            return b;
        }

        @Override
        public ValB marshal(ClassB v) throws Exception {
            ValB b = new ValB();
            b.text = v.text;
            return b;
        }

    }

    public static void main(String[] args) {
        try {
            JAXBContext context = JAXBContext.newInstance(ClassB.class);
            Unmarshaller unmarshaller = context.createUnmarshaller();
            unmarshaller.setAdapter(new MyAdapter()); // does not have an effect
            ClassA a = (ClassA) unmarshaller.unmarshal(new File("test.xml"));
            // do somthing with a
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}