XOM API for Processing XML with Java

[Elliotte Rusty Harold <elharo AT metalab.unc.edu>]

At 10:33 AM +0200 9/19/02, Laurent Bihanic wrote:


>  - Automatic detach: Having to call detach when moving nodes from 
> one place to another is realy cumbersome. A typical example is 
> sorting a list of children. Why not support an automatic-detach mode 
> so that programmer can move nodes freely?


It doesn't strike me as a huge burden on the programmer to have to 
detach a node first. I think two XOM principles are at issue here:

1. There's exactly one way to do it: since we need a detach method 
for non-moves, we should not duplicate it as part of insert.

2. Least surprise: would a developer be more surprised to find out 
that a node had been automatically detached when they forgot it had a 
parent and got the exception? Or would it be more surprising to later 
discover that a node had been detached? I'm not sure.

My thinking is that moves from one part of the tree to another are a 
relatively rare operation, so I'm not too concerned with optimizing 
them for the client. Calling detach() and then inserting is not that 
much harder than just inserting. I am worried about someone 
accidentally inserting something they didn't mean to detach. I've 
made this mistake myself more than once, and personally I prefer to 
get the exception so I see  my error up front.
--

+-----------------------+------------------------+-------------------+
| Elliotte Rusty Harold | elharo AT metalab.unc.edu | Writer/Programmer |
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|          XML in a  Nutshell, 2nd Edition (O'Reilly, 2002)          |
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