Validating an ActionForm "conditionnally"

[Sobkowski, Andrej]

Hello,

I've been using the Struts Validator (nightly build of November) with no
problems for a few months (great work!).

Now I need to call the validation method of a specific "nested form" based
on a condition:

ParentForm
+useChild: boolean
+getChildForm:ChildForm

If useChild returns true, I want to call the validate(mapping, request) of
ChildForm (ie the nested form).

I thought that the validator only needed the "mapping.getAttribute()" (name
of the ActionForm) to perform the validation so I tried with the following
(ugly, I know):

if (parentForm.useChild()) {
        ActionMapping newMap = new ActionMapping();
        newMap.setAttribute("childForm"); 
        ActionErrors errors = parentForm.getChildForm().validate(newMap,
request);
}

The configuration is extremely basic:
- In struts-config.xml:
    <form-bean      name="childForm"
                    type="com.company.ChildForm"/>
- In validation.xml:
      <form name="childForm">
                ...
      </form>

I'm getting a NullPointerException in the validator's code.

What am I doing wrong? Is this a good way to handle the problem (I doubt
it...)? Any suggestions?

Thanks.

Andrej