Annotation @XmlElement write only?

Question

I'm new to java XML binding.

This is my class

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

/**
 * @author Martin Burchard
 * 
 */
@XmlRootElement(name = "user")
    public class User {
    private String id;
    private String nickname;
    private String email;
    private String password;

    @XmlElement(name = "id")
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    @XmlElement(name = "nickname")
    public String getNickName() {
        return nickname;
    }

    public void setNickName(String nickname) {
        this.nickname = nickname;
    }

    @XmlElement(name = "email")
    public String getEMail() {
        return email;
    }

    public void setEMail(String email) {
        this.email = email;
    }

    @XmlElement(name = "password")
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

During creation/registration of a user the password must be given, but later, when asking for userinformation, the XML should not contain the password element. Is it possible to define an Element as writeonly?

Answer 1

Note: I'm the EclipseLink JAXB (MOXy) lead and a member of the JAXB 2 (JSR-222) expert group.

MOXy has an @XmlReadOnly extension. The field/property annotated with @XmlReadOnly will be populated during an unmarshal (read), but will not be written during a marshal.

User

package forum10208143;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import org.eclipse.persistence.oxm.annotations.XmlReadOnly;

/**
 * @author Martin Burchard
 * 
 */
@XmlRootElement(name = "user")
public class User {
    private String id;
    private String nickname;
    private String email;
    private String password;

    @XmlElement(name = "id")
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    @XmlElement(name = "nickname")
    public String getNickName() {
        return nickname;
    }

    public void setNickName(String nickname) {
        this.nickname = nickname;
    }

    @XmlElement(name = "email")
    public String getEMail() {
        return email;
    }

    public void setEMail(String email) {
        this.email = email;
    }

    @XmlElement(name = "password")
    @XmlReadOnly
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

jaxb.properites

To specify MOXy as your JAXB provider you need to add a file called jaxb.properties in the same package as your domain model with the following entry:

javax.xml.bind.context.factory = org.eclipse.persistence.jaxb.JAXBContextFactory

Demo

package forum10208143;

import java.io.File;
import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(User.class);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum10208143/input.xml");
        User user = (User) unmarshaller.unmarshal(xml);

        System.out.println(user.getPassword());

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(user, System.out);
    }

}

input.xml

<?xml version="1.0" encoding="UTF-8"?>
<user>
    <id>jdoe</id>
    <nickname>Jane</nickname>
    <email>[email protected]</email>
    <password>secret</password>
</user>

Output

secret
<?xml version="1.0" encoding="UTF-8"?>
<user>
   <email>[email protected]</email>
   <id>jdoe</id>
   <nickname>Jane</nickname>
</user>