Is it possible to use JAXB to map from schema to a java.util.Map?

Question

I have an existing XML schema that contains a type that I would like to map to a Java Map of some sort using JAXB. My build process takes the schema and creates the beans. I would like to customize this process by having one of the complexTypes in my schema map to a java.util.Map. I've read somewhere that JAXB "can't do interfaces." I'm not sure if that applies in this case, but if so I'd be fine with it mapping to a HashMap. Also, it doesn't necessarily have to be the complexType that maps to a Map, it could be an element if that's what's required.

I control my JAXB generation using a .xjb file, so I'm looking for some <jaxb:bindings> to put in there. I've tried the following, but it does not work:

<jaxb:bindings schemaLocation="myschema.xsd" node="/xs:schema">
    <jaxb:globalBindings>
        <jaxb:serializable uid="1"/>
    </jaxb:globalBindings>
    <jaxb:schemaBindings>
        <jaxb:package name="com.myschema.client.types"/>
    </jaxb:schemaBindings>
    <jaxb:bindings node="//xs:complexType[@name='MapType']">
            <jaxb:javaType name="java.util.HashMap"
            parseMethod="com.myschema.common.MapConverter.parseObjectToMap"
            printMethod="com.myschema.common.MapConverter.printMapToObject" />
    </jaxb:bindings>
</jaxb:bindings>

Edit: I've added more detail on the above binding that I've already tried. It generates the following error during schema compile:

[jaxb] [ERROR] compiler was unable to honor this javaType customization. It is attached to a wrong place, or its inconsistent with other bindings.

---

<jaxb:javaType> will not work because it can only be used for mapping between XML Schema primitives and Java types . Since I want to map between a complex type and a Java type, I cannot use this.

Answer 1

Your XJC file is using the "standard" javaType directive, which I believe is limited to converting String values to and from a representative java type. As such, it's only suitable for converting simple element and attribute content.

The XJC tool provides an enhanced version of javaType , which in theory should be able to handle more complex structures. Unfortunately, this has yet to be implemented:

https://java.net/jira/browse/JAXB-209 (unresolved)

For instance, being able to map a schema type to a HashMap might be a likely requirement for those using model driven design/implementation. AFAICS, this is not possible today. Therefore, one must manually edit the generated code.

Looks like you're out of luck.

Answer 2

Have you looked at example here (Customized mapping of HashMap): http://java.sun.com/javase/6/docs/api/javax/xml/bind/annotation/adapters/XmlAdapter.html

Need to create custom XmlAdapter I'm afraid.