Question

I’m trying to use MOXy to generate a specifically formatted response for a front end client to make it easier for them to determine specific relationships. This is a bit of a contrived example, but I’m trying to do something like the following…

public class Person {
    private Integer id;

    private String name;

    private Address address;
}

public class Address {
    private String street;

    private String locality;

    private String state;

    private String zip;
}

public class PersonCollectionResponse {
    private Set<Person> people;

    public Set<Person> getPeople() {
        return this.people;
    }

    private int getCount() {
        return this.people.size();
    }
}

…and would like to end up with a result like…

{
    "meta": {
        "count": 2
    },

    "people": [{
        "id": 1,
        "name": "Danny Parker",
        "contact": {
            "locality": "Zoo York",
            "state": "New York"
        },
    }, {
        "id": 2,
        "name": "Oscar the Grouch",
        "contact": {
            "locality": "San Francisco",
            "state": "California"
        }

    }],

    "mappings": [{
        "person": 1,
        "zip": 10014
    }, {
        "person": 2,
        "zip": 94102
    }]
}

Now the “people” set isn’t very hard, but I’m stuck on how to get the mappings to work when writing the EclipseLink OXM metadata. I’m looking for a way to redefine how people get listed so that I can get my mapping.

<xml-element java-attribute="people">
    <xml-element java-attribute="id" xml-path="@id" />
    <xml-element java-attribute="zip" xml-path="@zip" />
</xml-element>

Not I get that might now be possible. So I created a getMappings on the PersonCollectionResponse that returns a List> that it generates from the people. Now this isn’t ideal, but there are worse things. But when it is written out, the map objects are strings like so…

"mappings": ["{person: 1, zip: 10014}", "{person: 2, zip: 94102}"]

So I guess my questions are one of these…

1. How can I display an element a second time but with a different output?
2. How can I output maps without them being quoted as strings?

Worst case scenario I guess is I make my set of generic maps into a new class objects and provide a schema for them too, but that is something I’d like to avoid.

Answer 1

Currently MOXy does not allow you to split the representation of a single instance into multiple locations within a JSON (or XML) tree. Please enter an enhancement request for the type of support you would like to see:

• https://bugs.eclipse.org/bugs/enter_bug.cgi?product=EclipseLink

Below I’ll demonstrate how to map portions of your JSON message.

PARTIAL ANSWER #1

Below I’ll describe how to map your model to the following JSON message:

{
   "meta" : {
      "count" : 2
   },
   "people" : [ {
      "id" : 1,
      "name" : "Danny Parker",
      "contact" : {
         "locality" : "Zoo York",
         "state" : "New York"
      }
   }, {
      "id" : 2,
      "name" : "Oscar the Grouch",
      "contact" : {
         "locality" : "San Francisco",
         "state" : "California"
      }
   } ]
}

oxm.xml

<?xml version="1.0"?>
<xml-bindings
    xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
    package-name="forum11870107">
    <java-types>
        <java-type name="PersonCollectionResponse">
            <java-attributes>
                <xml-element java-attribute="count" xml-path="meta/count/text()"/>
            </java-attributes>
        </java-type>
        <java-type name="Person">
            <xml-type prop-order="id name address"/>
            <java-attributes>
                <xml-element java-attribute="address" name="contact"/>
            </java-attributes>
        </java-type>
        <java-type name="Address">
            <java-attributes>
                <xml-transient java-attribute="zip"/>
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>

---

PARTIAL ANSWER #2

Now I’ll describe how to map your model to the following JSON message:

{
   "meta" : {
      "count" : 2
   },
   "mappings" : [ {
      "person" : 2,
      "zip" : "94102"
   }, {
      "person" : 1,
      "zip" : "10014"
   } ]
}

oxm.xml

<?xml version="1.0"?>
<xml-bindings
    xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
    package-name="forum11870107">
    <java-types>
        <java-type name="PersonCollectionResponse">
            <java-attributes>
                <xml-element java-attribute="count" xml-path="meta/count/text()"/>
                <xml-element java-attribute="people" name="mappings"/>
            </java-attributes>
        </java-type>
        <java-type name="Person">
            <xml-type prop-order="id address"/>
            <java-attributes>
                <xml-element java-attribute="id" name="person"/>
                <xml-transient java-attribute="name"/>
                <xml-element java-attribute="address" xml-path="."/>
            </java-attributes>
        </java-type>
        <java-type name="Address" xml-accessor-type="NONE">
            <java-attributes>
                <xml-element java-attribute="zip"/>
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>

---

DEMO CODE

The same demo code can be used with both partial solutions:

package forum11870107;

import java.util.*;
import javax.xml.bind.*;

import org.eclipse.persistence.jaxb.JAXBContextProperties;

public class Demo {

    public static void main(String[] args) throws Exception {
        Map<String, Object> properties = new HashMap<String, Object>(1);
        properties.put(JAXBContextProperties.OXM_METADATA_SOURCE, "forum11870107/oxm.xml");
        properties.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
        properties.put(JAXBContextProperties.JSON_INCLUDE_ROOT, false);
        JAXBContext jc = JAXBContext.newInstance(new Class[] {PersonCollectionResponse.class}, properties);

        PersonCollectionResponse pcr = new PersonCollectionResponse();

        Person person1 = new Person();
        person1.setId(1);
        person1.setName("Danny Parker");
        pcr.getPeople().add(person1);
        Address address1 = new Address();
        address1.setLocality("Zoo York");
        address1.setState("New York");
        address1.setZip("10014");
        person1.setAddress(address1);

        Person person2 = new Person();
        person2.setId(2);
        person2.setName("Oscar the Grouch");
        pcr.getPeople().add(person2);
        Address address2 = new Address();
        address2.setLocality("San Francisco");
        address2.setState("California");
        address2.setZip("94102");
        person2.setAddress(address2);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(pcr, System.out);
    }

}

---

DOMAIN MODEL

Below is the domain model that was used for both partial solutions:

PersonCollectionResponse

package forum11870107;

import java.util.*;

public class PersonCollectionResponse {
    private Set<Person> people = new HashSet<Person>();

    public Set<Person> getPeople() {
        return this.people;
    }

    public void setPeople(Set<Person> people) {
        this.people = people;
    }

    public int getCount() {
        return this.people.size();
    }

}

Person

package forum11870107;

public class Person {
    private Integer id;

    private String name;

    private Address address;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

}

Address

package forum11870107;

public class Address {

    private String street;
    private String locality;
    private String state;
    private String zip;

    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    public String getLocality() {
        return locality;
    }

    public void setLocality(String locality) {
        this.locality = locality;
    }

    public String getState() {
        return state;
    }

    public void setState(String state) {
        this.state = state;
    }

    public String getZip() {
        return zip;
    }

    public void setZip(String zip) {
        this.zip = zip;
    }

}

jaxb.properties

To specify MOXy as your JAXB provider you need to include a file called jaxb.properties in the same package as your domain model with the following entry (see: http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html.

javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory