Ability to configure a XStream subclass on XStreamMarshaller [SPR-6037]

[spring-projects-issues]

Karthik Gurumurthy opened SPR-6037 and commented

This is about XStreamMarshaller.

http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/oxm/xstream/XStreamMarshaller.html

XStream allows you to customize XStream by specifying a MapperWrapper like so -

class MyXStream extends XStream {

    @Override
    protected MapperWrapper wrapMapper(MapperWrapper next) {
        // TODO Auto-generated method stub
        return new MyClassMapper(next);
    }

}

But Spring 3.x XStreamMarshaller instantiates a XStream instance by default.
So I'm not sure how we can supply our MapperWrapper .

I was wondering if Spring 3.x can provide a hook method that allows one to return their own custom XStream instance.
Or an option to specify our XStream subclass class. (XStreamMarsheller.setXStreamClass(Class xstreamClass);
You can probably use XStream.class by default.
I guess you guys know best how to achieve this.

I see that a method

protected void customizeXStream(com.thoughtworks.xstream.XStream xstream)

exists on XStreamMarshaller. But what I was looking for is a hook that allows us to specify our own XStream custom subclass.

Since Spring 3.x is not final yet, I was wondering if this hook can be added.

thanks!

---

Affects: 3.0 M4

Referenced from: commits 5c2d637

[spring-projects-issues]

Arjen Poutsma commented

I've made the getXstream method non-final, so that you can override that and return your own custom XStream instance.

[spring-projects-issues]

Erez Mazor commented

Since the proposed XStream implementation for Mapperwrapper is to extend XStream overriding the wrapMapper method) to implement the solution above you'd have to extend XStreamMarshaller and keep another instance of XStream in the extending class (overriding the getXStream method to supply the second instance).

This will in effect cause two instances of XStream to be created. Why not move the XStream private member instantiation to an overridable method createXStream

private final XStream xstream = createXStream();

protected XStream createXStream() {
	return new XStream();
}

This would allow extending the marshaller and control of the XStream instantiation. This blog shows an alternate method to control XStream mapping of specific classes with spring but it would be nice to be able to use XStream's global mapping intervention feature.