JAX-B - How to map a schema element to an existing Java class

Question

Possible Duplicate:
jaxb xjc mapping to existing domain objects

I am using JAX-B to generate Java classes from an XML schema.

There is one element in my schema that I would like to bind to a Java class that exists in my project. My binding is done in a .xjb file. I have tried several approaches but can't get anything to work.

Is this possible? If so, how?

Here is a smaller example of my problem:

My Existing Java class:

package com.existing; 

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlType;

@XmlAccessorType(XmlAccessType.FIELD)
public class Existing {
    private String prop; 
    public String getProp() { return prop; }
    public void setProp(String prop) { this.prop = prop; }
}

My Schema:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
     targetNamespace="http://www.baloiselife.com/xpression/policy"
     xmlns="http://www.baloiselife.com/xpression/policy" >

<xs:element name="root_node">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="some_other_propery" type="xs:string"/>
      <!-- I want this element to map onto my existing Java class -->
      <xs:element name="special_element" type="existing_type" minOccurs="0" />
    </xs:sequence>
  </xs:complexType>
</xs:element>

<!-- I want this element to be ignored, and instead my Java class used -->
<xs:complexType name="existing_type">
  <xs:sequence>
    <xs:element name="prop" type="xs:string" minOccurs="0" />
  </xs:sequence>
</xs:complexType>

So any ideas what my binding should be? I tried using the jxb:class setting, but could not get it to work. My end result has two requirements:

1. The ExistingType class is not generated from the Schema
2. The RootNode class has an element of type Existing, which maps to my existing Java class

Answer 1

You can use an external binding file to configure XJC to do what you want.

binding.xjb

<jxb:bindings 
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:jxb="http://java.sun.com/xml/ns/jaxb"
    version="2.1">

    <jxb:bindings schemaLocation="yourSchema.xsd">
        <jxb:bindings node="//xs:complexType[@name='existing_type']">
            <jxb:class ref="com.existing.Existing"/>
        </jxb:bindings>
    </jxb:bindings>
</jxb:bindings>

XJC Call

xjc -d outputDir -b binding.xjb yourSchema.xsd