import javax.xml.bind.*;
import a.JustAType;
import com.sun.xml.bind.marshaller.NamespacePrefixMapper;

public class JAXBSample {

    public static void main(String args[]) throws javax.xml.bind.JAXBException{
        try {
            JAXBContext jc = JAXBContext.newInstance("a");            
            a.ObjectFactory aObj = new a.ObjectFactory();
            JustAType t = aObj.createJustAType();
            t.setFoo(true);
            JAXBElement<JustAType> e = aObj.createJustAnElement(t);

            marshal(jc, e, null);

            NamespacePrefixMapper m = new PreferredMapper();
            marshal(jc, e, m);

            m = new DeclareOnTopMapper();
            marshal(jc, e, m);
            
            m = new PreDeclaredMapper();
            marshal(jc, e, m);
            
        } catch(javax.xml.bind.JAXBException e) {
            e.printStackTrace();
        }
    }

    public static void marshal(JAXBContext jc, Object toMarshall, NamespacePrefixMapper mapper) {
        System.out.println("Mapper: " + ((mapper == null) ? " not set. " : (mapper.getClass().getSimpleName())));
        try {
            Marshaller m = jc.createMarshaller();
            m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
            if (mapper != null) {
                m.setProperty("com.sun.xml.bind.namespacePrefixMapper", mapper);
            }
            m.marshal(toMarshall, System.out);
            System.out.println("-----------------------");
        } catch(Exception e) {
            e.printStackTrace();
        }
    }

    public static class PreferredMapper extends NamespacePrefixMapper {
        @Override
        public String getPreferredPrefix(String namespaceUri, String suggestion, boolean requirePrefix) {
            return "mappedNamespace" + namespaceUri;
        }
    }

    public static class DeclareOnTopMapper extends PreferredMapper {
        @Override
        public String[] getPreDeclaredNamespaceUris() {
            return new String[] {"a", "b"};
        }
    }

    public static class PreDeclaredMapper extends PreferredMapper {
        @Override
        public String[] getContextualNamespaceDecls() {
            return new String[] {"a", "mappedNamespacea"};
        }
    }

}