XOM API for Processing XML with Java

[Wolfgang Hoschek <whoschek AT lbl.gov>]

Elliotte Rusty Harold wrote:
> > Here are some cosmetic patches against d24.
> > The first two avoid some code duplication, and the third makes it a 
> > bit more efficient.
>
> Have you measured this to prove it makes the code more efficient?

The first two patches make the code more readable and better structured, 
and performance difference should be negligible.

I presume you mean the third patch about iteration vs. recursion.
Nope, i haven't measured it. But what i gathered from CS studies and 
benchmarks years ago is that iteration is always faster than recursion 
because it avoids function calls, stack allocations and deallocations, 
processor register state switching, allows better compiler optimizations 
because it increases optimization scope, better register allocation, 
etc. So the bottom line is it is faster (but i don't know how much) and 
it certainly isn't slower. I've heard mails a while ago on the list that 
sounded a bit uneasy about the potential performance hit of extensive 
tree walking for correctness checking, so I thought that patch would 
help and certainly can't hurt, given that the proposed code is just as 
clean, concise and understandable as the old one.

If you believe isAncestor() is unlikely to ever be a hotspot, the 
discussion is moot of course.

Wolfgang.