JAXB unmarshal undefined elements to Map?

Question

I have an XML to unmarshall:

<?xml version="1.0" encoding="UTF-8"?>
<ROW id='1'>
   <MOBILE>9831138683</MOBILE>
   <A>1</A>
   <B>2</B>
</ROW>

I want to map it to a class:

import java.util.*;
import javax.xml.bind.annotation.*;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
import org.eclipse.persistence.oxm.annotations.XmlPath;

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class ROW {

    @XmlPath(".")
    @XmlJavaTypeAdapter(MapAdapter.class)
    private Map<String, Integer> map = new HashMap<String, Integer>();

    @XmlAttribute
    private int id;
    @XmlElement(name = "MOBILE")
    private int mobileNo;

}

For this I tried the bdoughan blog where it uses @XmlVariableNode("key") :

MapAdapter:

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

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

import org.eclipse.persistence.oxm.annotations.XmlVariableNode;

public class MapAdapter extends XmlAdapter<MapAdapter.AdaptedMap, Map<String, String>> {

    public static class AdaptedMap {

        @XmlVariableNode("key")
        List<AdaptedEntry> entries = new ArrayList<AdaptedEntry>();

    }

    public static class AdaptedEntry {

        @XmlTransient
        public String key;

        @XmlValue
        public String value;

    }

    @Override
    public AdaptedMap marshal(Map<String, String> map) throws Exception {
        AdaptedMap adaptedMap = new AdaptedMap();
        for(Entry<String, String> entry : map.entrySet()) {
            AdaptedEntry adaptedEntry = new AdaptedEntry();
            adaptedEntry.key = entry.getKey();
            adaptedEntry.value = entry.getValue();
            adaptedMap.entries.add(adaptedEntry);
        }
        return adaptedMap;
    }

    @Override
    public Map<String, String> unmarshal(AdaptedMap adaptedMap) throws Exception {
        List<AdaptedEntry> adaptedEntries = adaptedMap.entries;
        Map<String, String> map = new HashMap<String, String>(adaptedEntries.size());
        for(AdaptedEntry adaptedEntry : adaptedEntries) {
            map.put(adaptedEntry.key, adaptedEntry.value);
        }
        return map;
    }

}

Using this approach all the keys(MOBILE, id, A, B) are mapped inside the Map. I want to unmarshall such that all defined attributes the id, MOBILE are mapped to their attributes in POJO and rest all are mapped to Map.

How can this be achieved ?

Answer 1

I have a solution for you, but slightly different than what you try above.

Let's take the root class:

@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "ROW")
public class Row {

    @XmlAttribute
    private int id;
    @XmlElement(name = "MOBILE")
    private int mobileNo;

    @XmlMixed
    @XmlAnyElement
    @XmlJavaTypeAdapter(MyMapAdapter.class)
    private Map<String, String> otherElements;
}

And the adapter for turning the uknown values into a map:

import org.w3c.dom.Document;
import org.w3c.dom.Element;

import javax.xml.bind.annotation.adapters.XmlAdapter;
import javax.xml.parsers.DocumentBuilderFactory;
import java.util.HashMap;
import java.util.Map;

public class MyMapAdapter extends XmlAdapter<Element, Map<String, String>> {

    private Map<String, String> hashMap = new HashMap<>();

    @Override
    public Element marshal(Map<String, String> map) throws Exception {
        // expensive, but keeps the example simpler
        Document document = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();

        Element root = document.createElement("dynamic-elements");

        for(Map.Entry<String, String> entry : map.entrySet()) {
            Element element = document.createElement(entry.getKey());
            element.setTextContent(entry.getValue());
            root.appendChild(element);

        }

        return root;
    }


    @Override
    public Map<String, String> unmarshal(Element element) {
        String tagName = element.getTagName();
        String elementValue = element.getChildNodes().item(0).getNodeValue();
        hashMap.put(tagName, elementValue);

        return hashMap;
    }
}

This will put id and mobile number in the fields, and the rest, the uknown into a map.

The marshalling will not be exactly as the xml you showed. It puts a wrapper around the dynamic values and looks like this:

<ROW id="1">
    <MOBILE>1241204091</MOBILE>
    <dynamic-elements>
        <A>1</A>
        <B>2</B>
    </dynamic-elements>
</ROW>