h:dataTable validation

[Jeff Bowman]

I am using a h ataTable to display a list of items which allow user input. I need to do validation on these items, but the fields are related. So how do I do this?

<h ataTable id="foo"...>
<h:column id="type">
<h:selectOneMenu>
<f:selectItem ...>
...
</h:selectOneMenu>
</h:column>

<h:column id="size">
<h:selectOneMenu> ... </h:selectOneMenu>
</h:column>

<h:column id="sqfeet">
<h utputText .../>
</h:column>
</h ataTable>

So, I need to make sure that for each row, a type is specfied in the type column and either a size or a sqfeet, but not both. I have tried reading the book "core java server faces" from sun without gleaning any help and I have tried to google for htmldatatable validate, which google wants to turn into html data table validate, which doesn't find anything either.

Any help would be appreciated.

Thanks,
Jeff