JAXB polymorphism

Question

Hi,
I am using jaxb 1.0.4 and my shemas are as follows.,.
document.xsd
<xs:schema>
     <xs:element name="document" type="documentType"/>
     <xs:complexType name="documentType">
          <xs:sequence>
               <xs:element name="instance" type="xs:string"/>
               <xs:element name="version" type="xs:string"/>
               <xs:element name="event" type="EventType"/>
          </xs:sequence>
     </xs:complexType>
     <xs:complexType name="EventType" abstract="true">
          <xs:sequence>
               <xs:element name="event_type" type="xs:string"/>
          </xs:sequence>
     </xs:complexType>
</xs:schema>
<xs:schema>
     <xs:complexType name="AmendmentEventType">
          <xs:complexContent>
               <xs:extension base="EventType">
                    <xs:sequence>
                         <xs:element name="amendedBy" type="xs:string"/>
                         <xs:element name="book" type="BookType"/>
                    </xs:sequence>
               </xs:extension>
          </xs:complexContent>
     </xs:complexType>
     <xs:element name="amendmentEvent" type="AmendmentEventType"/>
</xs:schema>
In my java class I want to use something like this..
          Document document = objFactory.createDocument();
          AmendmentEventType amendmentEvent = objFactory.createAmendmentEventType();
          //set the fields in AmendmentEventType
          document.setEvent(amendmentEvent);
When I marshall the document object I get the following exception.
Location: obj: DocumentImpl@406199
com.sun.xml.bind.serializer.AbortSerializationException: tag name "AmendmentEventType" is not allowed. Pos
sible tag names are: <EventType>
Is this polymorphism not allowed in Jaxb?

Answer 1

hi Matt,
I think your expected output may be wrong, and the actual output be correct eg consider this code:
import java.util.*;
class Person {
     String name;
     public String toString() { return "Person("+name+")"; } }
class Employee extends Person {
     String title;
     public String toString() { return "Employee("+name+", "+title+")"; } }
public class JBTest {
     public static void main(String[]arg) {
          List l = new ArrayList();
          Person p = new Person();
          p.name="Joe Sample";
          Employee q = new Employee();
          q.name="Jane Sample Employee";
          q.title="Engineer";
          l.add(p);
          l.add(q);
          System.out.println(l);
which outputs
     [Person(Joe Sample), Employee(Jane Sample Employee, Engineer)]
So although the List is untyped (am not keeping up with generics..
sorry!) in the above code, even if it were a Person list it would still be legitimate to add an Employee to the list (since an Employee is-a
Person)
saying that, am not sure how you could achieve what you are trying? are you hoping for the object tree you construct not to be validated?
thanks,
asjf