CODEWITHSUNDEEP
javaxmljaxb
Sotirios Delimanolis
Sotirios Delimanolis

Reputation: 279880

XmlAdapter not called for adapting List to Map

I'm playing around with JAXB, so a lot of the questions I'm asking are just to see what's possible.

I have the following XML:

<bundleMappings>
    <mapping>
        <parameter attr = "value">asdas</parameter>
        <parameter attr = "value2">d123asdsad</parameter>
        <parameter attr = "value3">0</parameter>
    </mapping>
    <mapping>
        <parameter attr = "value">23123s</parameter>
        <parameter attr = "value2">qwerty</parameter>
        <!-- more parameter elements -->
    </mapping>
    <!-- more mapping elements -->
</bundleMappings>

In which I'd want the parameter elements to be in a Map<String, Parameter> instead of a List, where the key is the attr value and the value is the content of the element. I've followed some blog posts and come up with this.

@XmlRootElement(name = "bundleMmappings")
public class BundleMappings { 
    @XmlElement(name = "mapping")
    private List<Mapping> mMappings;

    //getters setters
}

@XmlAccessorType(XmlAccessType.FIELD) 
public class Mapping {
    @XmlElement
    @XmlJavaTypeAdapter(ParameterAdapter.class)
    private HashMap<String, Parameter> mParameterMap;

    //getters setters
}

@XmlAccessorType(XmlAccessType.FIELD)
public class Parameter {
    @XmlAttribute(name = "attr")
    private String mName;

    @XmlValue
    private String mValue;

    //getters setters
} 

@XmlAccessorType(XmlAccessType.FIELD)
public class Parameters {
    @XmlElement(name = "parameters")
    private List<Parameter> parameters = new LinkedList<>();

    //getters setters
}

And the adapter:

public class ParameterAdapter extends XmlAdapter<Parameters, Map<String, Parameter>> {

    @Override
    public Parameters marshal(Map<String, Parameter> map) throws Exception {
        Parameters params = new Parameters();
        params.setParameters(new ArrayList<Parameter>());
        for (String name : map.keySet()) {
            Parameter p = new Parameter();
            p.setName(name);
            p.setValue(map.get(name).getValue());
            params.getParameters().add(p);
        }
        return params;
    }

    @Override
    public Map<String, Parameter> unmarshal(Parameters value) throws Exception {
        Map<String, Parameter> map = new HashMap<>();
        for (Parameter parameter : value.getParameters()) {
            map.put(parameter.getName(), parameter);
        }
        return map;
    }
}

I did a small unmarshalling test with breakpoints in the Adapter unmarshal and it isn't called at all. Why not?

I also tried annotating the Mapping class List with @XmlElement(name = "parameter"). In this case the unmarshall was called but the Parameters parameter passed to it had an empty list.

Edit

If I try to marshal:

<bundleMappings>
    <mapping>
        <mParameterMap>
            <parameter name="HOME_NETWORK_ID">12345</parameter>
        </mParameterMap>
    </mapping>
</bundleMappings>

Upvotes: 2

Views: 1934

Answers (1)

bdoughan
bdoughan

Reputation: 148977

When you specify an XmlAdapter on a collection property it applies to the items in the collection.

public class Mapping {
    @XmlElement
    @XmlJavaTypeAdapter(ParameterAdapter.class)
    private List<Parameter> mParameters;

    //getters setters
}

This means ParameterAdapter would need to look something like, where Foo is what you want to convert Parameter to:

public class ParameterAdapter extends XmlAdapter<Foo, Parameter> {

Map Example

Below is a link to an example from my blog where XmlAdapter is used on a Map property:

Upvotes: 2

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