POJO for Node with mixed items

[Madhan Raj]

<Root ref="abc">
    <Page ref="p1">
        <Object ref="o1"></Object>
        <ObjectGroup ref="o2">
            <Object ref="o1"></Object>
            <Object ref="o2"></Object>
        </ObjectGroup>
        <Object ref="o3"></Object>
        <Object ref="o4"></Object>
    </Page>
</Root>

I want to wite a POJO for the above xml. Asked a question is StackOverFlow

The root will have n Page and Page will have n Object as well as n ObjectGroup and ObjectGroup will have n Object. where n >= 0

I looked into Polymorphic de serialization as well. But How to handle this situation

[Hugo Vandeputte]

Hello,
You could use the following classes :
A base class Element  mapping the ref string:

public class Element {
    @JacksonXmlProperty(isAttribute = true)
    private String ref;
   
    public String getRef() {
        return ref;
    }
}

A Root class:

public class Root extends Element{
    @JsonProperty(value="Page")
    @JacksonXmlElementWrapper(useWrapping = false)
    List<Page> page;
   
    public List<Page> getPage() {
        return page;
    }
}

A page class

public class Page {
    @JacksonXmlProperty(isAttribute = true)
    private String ref;
   
    @JsonProperty(value="Object")
    @JacksonXmlElementWrapper(useWrapping = false)
    List<Element> pageObject;
   
    @JsonProperty(value="ObjectGroup")
    ObjectGroup objectGroup;

}

And an ObjectGroup class

public class ObjectGroup extends Element{
    @JsonProperty(value="Object")
    @JacksonXmlElementWrapper(useWrapping = false)
    List<Element> elementList;
   
    public List<Element> getElementList() {
        return elementList;
    }
}

And as main testing method:

public static void main(String[] args) throws JsonParseException, JsonMappingException, IOException {
        // TODO Auto-generated method stub
        String xmlString="<Root ref=\"abc\">\n" +
                "    <Page ref=\"p1\">\n" +
                "        <Object ref=\"o1\"></Object>\n" +
                "        <ObjectGroup ref=\"o2\">\n" +
                "            <Object ref=\"o1\"></Object>\n" +
                "            <Object ref=\"o2\"></Object>\n" +
                "        </ObjectGroup>\n" +
                "        <Object ref=\"o3\"></Object>\n" +
                "        <Object ref=\"o4\"></Object>\n" +
                "    </Page>\n" +
                "</Root>";
        ObjectMapper xmlMapper=new XmlMapper();
        Root root=xmlMapper.readValue(xmlString, Root.class);
    }