Struts Validator Message Arguments

[Dan Ludwig]

I think it's great that I can compose validation failure messages using a resource properties file, passing in different resource keys as arguments like so:

<field property="fieldname" depends="required">
<msg name="reqmsg" key="form.add.errors.fieldname.required" />
<arg0 key="form.fieldname.display" />
</field>

..Which has a properties resource that results in the message:

<span class="error-field">Field Name</span> is required.

So, what if I want to use a runtime value as a message argument? Is that possible with the Struts Validator? How is it accomplished? For example, my target message would be something like:

The <span class="error-field">Username</span> <span class="error-value">root</span> is already taken by another user. Please choose a different <span class="error-field">Username</span>.

... The message properties would look something like:

user.add.errors.username.taken=The <span class="error-field">{0}</span> <span class="error-value">{1}</span> is already taken by another user. Please choose a different <span class="error-field">{0}</span>.

But, I can't find any documentation on how to configure validation.xml to pass the argument in from a FormBean property. Am I chasing my tail, or is this possible?

Thanks,

Dan