xml-dev - RE: String interning (WAS: SAX2/Java: Towards a final form)

[Miles Sabin <msabin@cromwellmedia.co.uk>]

David Brownell wrote,
> Literals are already interned.  It's in the language 
> spec. Look at the javadoc for java.lang.String.intern () 

Good point ... and one which I'd <blush>unaccountably
overlooked</blush>.

I don't think this materially affects my argument tho',
because the only time where the performance difference
between,

  foo == "literal"

and,

  foo.equals("literal")

is going to be significant is where there are long chains
of comparisons, ie.,

  if(foo == "elem1")
    // do stuff for elem1
  else if(foo == "elem2")
    // do stuff for elem2
  
  // ... repeat many times ...

  else if (foo == "elemn")
    // do stuff for elemn

where it'd be a far better idea (both from performance and 
software design POVs) to do something like,

  ElementHandler handler =
    (ElementHandler)someTable.lookup(foo);

  handler.doStuffForElement();

Cheers,


Miles

-- 
Miles Sabin                       Cromwell Media
Internet Systems Architect        5/6 Glenthorne Mews
+44 (0)20 8817 4030               London, W6 0LJ, England
msabin@cromwellmedia.com          http://www.cromwellmedia.com/

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