How do you create a POJO containing a list that the container has attributes?

Question

How do you create a POJO containing a list that the container has attributes?

Typically when creating a POJO of a list you do it the following way:

To represent the following XML structure:

<folder>
    <messages>
        <message>
            <subject>XXXX</subject>
            ...
        </message>
        <message>
            <subject>XXXX</subject>
            ...
        </message>
    </messages>
</folder>

@XmlRootElement(name = "folder")
public class Folder {
    @XmlElement
    private List<Message> messages;
    ...
}

@XmlRootElement(name = "message")
public class Message {
    @XmlElement
    private String subject;
    ...
}

But how do you represent a POJO when there are attributes at the messages tag? i.e.

<folder>
    <messages total="45" start="3">
        <message>
            <subject>XXXX</subject>
            ...
        </message>
        <message>
            <subject>XXXX</subject>
            ...
        </message>
    </messages>
</folder>

Do you create a POJO specifically for messages and then map a List of Message with an annotation of @XmlValue or something along those lines?

Thanks for your help guys.

Answer 1

The following approach could be used with any JAXB (JSR-222) implementation.

Messages

Using just the standard JAXB (JSR-222) APIs you will need to introduce a Messages class to your model.

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

public class Messages {

    @XmlElement(name="message")
    private List<Message> messages;

    @XmlAttribute
    private int start;

    @XmlAttribute
    public int getTotal() {
        if(null == messages) {
            return 0;
        } else {
            return messages.size();
        }
    }

}

Folder

Then you will need to modify your Folder class to reference the new Messages class.

import javax.xml.bind.annotation.*;

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

    private Messages messages;
}

Message

import javax.xml.bind.annotation.*;

@XmlAccessorType(XmlAccessType.FIELD)
public class Message {

    private String subject;

}