Question

I am trying to map the below interface using Moxy’s XML Metadata extension. But when I try to load it, I am getting the below error. I can’t add a public constructor to the AddressType as it is an enum.

My question is: Why is Moxy impl looking at AddressType even though I didn’t specify in the xml metadata?

public interface TokenizedUnitedStatesAddress
{
    class AddressType extends Enum
    {
        public static final AddressType STREET = new AddressType("street");    
        public static final AddressType PO_BOX = new AddressType("poBox");    
        public static final AddressType RURAL_ROUTE = new AddressType("ruralRoute");

        public static AddressType getEnum(final String type)
        {
            return (AddressType) getEnum(AddressType.class, type);
        }

        protected AddressType(final String name)
        {
            super(name);
        }
    }

    String getApartmentNumber();

    //removed other getters for brevity
}

---

<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.eclipse.org/eclipselink/xsds/persistence/oxm http://www.eclipse.org/eclipselink/xsds/eclipselink_oxm_2_4.xsd"
   version="2.4" package-name="com.abc.ic.domain.country.us">
   <java-types>
      <java-type name="TokenizedUnitedStatesAddress">
         <xml-root-element />
         <xml-type
            prop-order="StreetPreDirection StreetNumber StreetName StreetType StreetPostDirection UnitDesignator UnitNumber AddressLine1 AddressLine2 City State PostalCode CarrierRoute LengthAtAddress OwnershipStatus" />
         <java-attributes>
            <xml-element name="StreetPreDirection" java-attribute="preDirectional" />
            <xml-element name="StreetNumber" java-attribute="houseNumber" />
            <xml-element name="StreetName" java-attribute="streetName" />
            <xml-element name="StreetType" java-attribute="streetType" />
            <xml-element name="StreetPostDirection" java-attribute="postDirection" />
            <xml-element name="UnitNumber" java-attribute="apartmentNumber" />
            <xml-element name="AddressLine1" java-attribute="primaryAddress" />
            <xml-element name="AddressLine2" java-attribute="secondaryAddress" />
            <xml-element name="City" java-attribute="cityName" />
            <xml-element name="State" java-attribute="stateAbbreviation" />
            <xml-element name="PostalCode" java-attribute="zipCode" />
         </java-attributes>
      </java-type>
   </java-types>
</xml-bindings>

---

javax.xml.bind.JAXBException: 
Exception Description: The class com.abc.ic.domain.country.us.TokenizedUnitedStatesAddress$AddressType requires a zero argument constructor or a specified factory method.  Note that non-static inner classes do not have zero argument constructors and are not supported.
 - with linked exception:
[Exception [EclipseLink-50001] (Eclipse Persistence Services - 2.4.0.v20120608-r11652): org.eclipse.persistence.exceptions.JAXBException
Exception Description: The class com.abc.ic.domain.country.us.TokenizedUnitedStatesAddress$AddressType requires a zero argument constructor or a specified factory method.  Note that non-static inner classes do not have zero argument constructors and are not supported.]
    at org.eclipse.persistence.jaxb.JAXBContext$TypeMappingInfoInput.createContextState(JAXBContext.java:908)
    at org.eclipse.persistence.jaxb.JAXBContext.<init>(JAXBContext.java:157)
    at org.eclipse.persistence.jaxb.JAXBContextFactory.createContext(JAXBContextFactory.java:170)
    at org.eclipse.persistence.jaxb.JAXBContextFactory.createContext(JAXBContextFactory.java:157)
    at org.eclipse.persistence.jaxb.JAXBContextFactory.createContext(JAXBContextFactory.java:117)
    at org.eclipse.persistence.jaxb.JAXBContextFactory.createContext(JAXBContextFactory.java:107)

Answer 1

I am a developer on the EclipseLink MOXy team, and I’ve been looking at this issue. You are correct as to why the AddressType class was introspected, and I see that you have a workaround.

Another solution would be to create an XmlAdapter that can convert between Apache Enum classes and their XML (string) representation, as follows:

import javax.xml.bind.annotation.adapters.XmlAdapter;

import org.apache.commons.lang.enums.Enum;

import enumbindings.TokenizedUnitedStatesAddress.AddressType;

public class ApacheEnumAdapter extends XmlAdapter<String, Enum> {

    public ApacheEnumAdapter() {
    }

    @Override
    public Enum unmarshal(String s) throws Exception {
        return AddressType.getEnum(s);
    }

    @Override
    public String marshal(Enum e) throws Exception {
        if (null == e) {
            return null;
        }
        return e.getName();
    }

}

And then hook up the adapter in your bindings file like this:

...
<xml-element name="StreetType" java-attribute="streetType">
    <xml-java-type-adapter value="enumbindings.ApacheEnumAdapter" />
</xml-element>
...

As far as the bug you entered, EclipseLink is actually behaving correctly in this situation, we do not do any special handling of Apache Commons classes and so a default no-arg constructor (or some other handling mechanism) is still required. However I will update your bug and change it to an enhancement request to support Apache Enums out of the box, and we will evaluate it.

Thanks,

Rick