ADF FACES: af:column sortProperty not working on EL expression

Question

If you use an EL expression as a sortProperty on an af:column element, the column is not actually made sortable.
For example, if you have this:
<af:column sortProperty="#{row.phys.name.firstName}" sortable="true">
<f:facet name="header">
<af:outputText value="First Name"/>
</f:facet>
<af:outputText value="#{row.phys.name.firstName}"/>
</af:column>
The data is properly represented in the table, but the column is not sortable. If you create a "firstName" property directly on the objects in the table data and use a specification like what's shown below, then the column is sortable.
<af:column sortProperty="firstName" sortable="true">
Why this difference in behavior? It's very common to have complex object trees and only allowing direct properties to be sortable is a significant limitation.
So, is this a bug, or is it working as designed?

Answer 1

My data model is fairly deep, with subordinate objects for things like Names and Addresses. So, a Physician object contains numerous sub-objects that can be accessed using simple methods GetName() and getAddress().
Given an af:table in which I'm trying to display information on a physician, I'd like to be able to reference the nested data directly and still have it be sortable. Thus, I would like to be able to specify sortProperty="phys.name.lastName" and have the column sort on the value of that nested property.
Is that enough of an explanation? If not, I'd be happy to expand on it.
Also, given that you say it is working as designed, I'm assuming that it was designed to be a simple property name directly accessible on the bound variable, correct?
Thanks.