Java – what should JAXB return from the ‘beforemarshal (marshaler)’ method?

First of all, I'm not talking about Marshall #listener

Anyone can tell me what should be returned from the Boolean before Marshal (marshaler) method?

/**
 * Where is apidocs for this method?
 * What should I return for this?
 */
boolean beforeMarshal(Marshaller marshaller);

Anyway, I mean to use this method to convert JPA's long @ ID to JAXB's string @ xmlid, jaxb-ri and Moxy

[Edit] a void version seems to work Is this just a documentation problem?

Solution

Brief answer

Boolean return type is a document error The return type should be invalid

The answer is long

You can use eclipse link JAXB (Moxy) because it has no restriction that the field / property annotated with @ xmlid is of type string

You can use the xmladapter to map the use cases that support you:

IDAdapter

This xmladapter converts a long value to a string value to meet the requirements of the @ xmlid annotation

package forum9629948;

import javax.xml.bind.DatatypeConverter;
import javax.xml.bind.annotation.adapters.XmlAdapter;

public class IDAdapter extends XmlAdapter<String,Long> {

    @Override
    public Long unmarshal(String string) throws Exception {
        return DatatypeConverter.parseLong(string);
    }

    @Override
    public String marshal(Long value) throws Exception {
        return DatatypeConverter.printLong(value);
    }

}

B

@The xmljavatypeadapter annotation specifies the xmladapter:

package forum9629948;

import javax.xml.bind.annotation.*;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

@XmlAccessorType(XmlAccessType.FIELD)
public class B {

    @XmlAttribute
    @XmlID
    @XmlJavaTypeAdapter(IDAdapter.class)
    private Long id;

}

One

package forum9629948;

import javax.xml.bind.annotation.*;

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

    private B b;
    private C c;

}

C

package forum9629948;

import javax.xml.bind.annotation.*;

@XmlAccessorType(XmlAccessType.FIELD)public class C {

    @XmlAttribute
    @XmlIDREF
    private B b;

}

demonstration

package forum9629948;

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

public class Demo {

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

        File xml = new File("src/forum9629948/input.xml");
        Unmarshaller unmarshaller = jc.createUnmarshaller();
        A a = (A) unmarshaller.unmarshal(xml);

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

}

Input and output

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<a>
    <b id="123"/>
    <c b="123"/>
</a>