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I am trying to create a REST web-service in Java using RestEasy with the design similar to the example classes that I have shown below:

@Path("/rest")
public class TestRestService {
    @GET
    @Path("/test")
    @Produces("application/xml")
    public Response sayTestXml() {
        return getImplementation();
    }

    public Response getImplementation() {
        IInterface refToImpl = TestService.getImplementation(); 
        return Response.status(Status.OK).entity(refToImpl).build();
    }
}

public class TestService {
    public static IInterface getImplementation() {
        IInterface ref = new Implementation();
        return ref;
    }
}

public interface IInterface {
    public long getLong();
    public String getString();
    public boolean getBoolean();
    public List<IRelatedInterface> getRelations();
}

public interface IRelatedInterface {
    public float getFloat();
    public char getChar();
    public byte getByte();  
}

@XmlRootElement(name="interface")
@XmlAccessorType(XmlAccessType.PROPERTY)
public class Implementation implements IInterface {

    @XmlElement(name="tlong",  required=true)
        public long getLong() {
        return 42;
    }

    @XmlElement(name="tstring", required=true)
    public String getString() {
        return "test";
    }

    @XmlElement(name="tboolean", required=true)
    public boolean getBoolean() {
        return false;
    }

    @XmlElementWrapper(name = "relations")
    @XmlElement(name = "relation", required=false)
    public List<IRelatedInterface> getRelations() {

        List<IRelatedInterface> list = new ArrayList<IRelatedInterface>();
        RelatedImplementation impl = new RelatedImplementation();
        list.add(impl);

        return list;
    }
}

@XmlRootElement(name="relatedInterface")
@XmlAccessorType(XmlAccessType.PROPERTY)
public class RelatedImplementation implements IRelatedInterface {

    @XmlElement(name="tfloat",  required=true)
    public float getFloat() {
        return 1.23f;
    }

    @XmlElement(name="tchar",  required=true)
    public char getChar() {
        return 'A';
    }

    @XmlElement(name="tbyte",  required=true)
    public byte getByte() {
        return 'Z';
    }
}

So, when I try this design then JAXB complains as below:

com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 2 counts of IllegalAnnotationExceptions com.intuit.whitespace.IRelatedInterface is an interface, and JAXB can't handle interfaces. this problem is related to the following location: at com.intuit.whitespace.IRelatedInterface at public java.util.List com.intuit.whitespace.Implementation.getRelations() at com.intuit.whitespace.Implementation com.intuit.whitespace.IRelatedInterface does not have a no-arg default constructor. this problem is related to the following location: at com.intuit.whitespace.IRelatedInterface at public java.util.List com.intuit.whitespace.Implementation.getRelations() at com.intuit.whitespace.Implementation

My question is, is there a way to solve this? I have tried some things but none of them have worked. I am considering Spring OXM or a MessageBodyWriter based solution, but I wanted to ask if there were any other suggestions that would help me better?

sinha
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  • I am going to try http://stackoverflow.com/questions/4931960/jersey-rest-jaxb-error-mapping-an-interface as this did not come up when I searched for similar questions. – sinha Mar 02 '12 at 13:32

1 Answers1

0

Okay, I solved it by making the following changes:

Used the type attribute in @XmlElement 

public class Implementation implements IInterface {

    @XmlElementWrapper(name = "relations")
    @XmlElement(name = "relation", required=false, type=RelatedImplementation.class)
    public List<IRelatedInterface> getRelations() {
        ....
    }
}

That is all!

sinha
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