XOM API for Processing XML with Java

["Bradley S. Huffman" <hip AT cs.okstate.edu>]

Elliotte Harold writes:

> While considering the possibility of allowing Nodes objects to be 
> canonicalized, it occurred to me to wonder whether the items in such a 
> list could be null. Apparently, they can be. This test passes:
> 
>      public void testNull() {
> 
>          Nodes nodes = new Nodes();
>          nodes.append(null);
>          assertEquals(null, nodes.get(0));
> 
>      }
> 
> 
> I'm not sure I ever really thought about this before. If I had, I think 
> I probably would have decided to throw a NullPointerException when 
> someone tried to insert null into the list, but it's not a strong 
> feeling. Now I'm equally weakly inclined to leave it alone; since it's 
> possible changing this now might break someone's code.
> 
> Still, it might be nice to have an absolute guarantee that the items in 
> a Nodes list or never null.
> 
> Would anyone care to argue one way or the other? i.e. that Nodes 
> definitely should or definitely should not allow null values?

I view Nodes as a place holder for results, not slots to be filled or left
empty. When nodes.size() > 0, I think the right thing is to have at least
one actual Node. Throw the exception.

Brad