CODEWITHSUNDEEP
javaxmljaxb
misco
misco

Reputation: 1952

How to unmarshall XML to this class?

I would like to unmarshall XML using JAXB unmarshaller to the object of this type.

public class Pair<T1,T2> implements Serializable {
    private T1 first;

    private T2 second;

    public Pair(T1 first, T2 second) {
        this.first = first;
        this.second = second;
    }

    public T1 getFirst() {
        return first;
    }

    public void setFirst(T1 first) {
        this.first = first;
    }

    public T2 getSecond() {
        return second;
    }

    public void setSecond(T2 second) {
        this.second = second;
    }
}


public class TripPair<T1,T2> extends Pair<T1,T2> {

    public TripPair(T1 first, T2 second) {
        super(first, second);
    }
}

public class Fare extends Pricing implements Comparable<Fare> {

    private List<TripPair<Integer,Integer>> trips = new LinkedList<>();
}

XML file 

<fareGroups>
    <trips>
        <second>37</second>
        <first>0</first>
    </trips>
</fareGroups>

XML file have also other data and it is unmarshalled, unfortunately data from elements first and second are not unmarshalled. I tried to add @XmlElement annotations on these fields to Pair class, but without sucesss.

Using XmlAdapter

public class PairAdapter extends XmlAdapter<String, Integer> {

    public String marshal(Integer val) throws Exception {
        return val.toString();
    }

    public Integer unmarshal(String val) throws Exception {
        return Integer.valueOf(val);
    }
}

public class Pair<T1,T2> implements Serializable {
    @XmlJavaTypeAdapter(PairAdapter.class)
    private T1 first;

    @XmlJavaTypeAdapter(PairAdapter.class)
    private T2 second;
}

Upvotes: 2

Views: 97

Answers (1)

bdoughan
bdoughan

Reputation: 148977

You will need to add a zero-arg constructor, or create an XmlAdapter for the Pair class to get it to unmarshal correctly (see: http://blog.bdoughan.com/2010/12/jaxb-and-immutable-objects.html).

UPDATE

I'm using JAXB marshaller for it and when I made a debugging of non-marshalled element, it has wrong type. ElementNSImpl instead of Integer.

As far as JAXB is concerned first and second will be treated as type Object, since it derives metadata at the class level Pair instenad of the type level Pair<Integer, Integer>. Because of this the XML will need to qualify the XML elements with the necessary type information. This is done using the xsi:type attribute. 

public class Pair<T1,T2> implements Serializable {
    private T1 first;

    private T2 second;

Try populating your object model with the data you want and then marshalling it and you will see what the XML should look like for the unmarshal operation.

Upvotes: 3

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