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From "Michael McCandless" <luc...@mikemccandless.com>
Subject Re: Token termBuffer issues
Date Fri, 20 Jul 2007 00:27:50 GMT
"Yonik Seeley" <yonik@apache.org> wrote:
> I had previously missed the changes to Token that add support for
> using an array (termBuffer):
> 
> +  // For better indexing speed, use termBuffer (and
> +  // termBufferOffset/termBufferLength) instead of termText
> +  // to save new'ing a String per token
> +  char[] termBuffer;
> +  int termBufferOffset;
> +  int termBufferLength;
> 
> While I think this approach would have been best to start off with
> rather than String,
> I'm concerned that it will do little more than add overhead at this
> point, resulting in slower code, not faster.
> 
> - If any tokenizer or token filter tries setting the termBuffer, any
> downstream components would need to check for both.  It could be made
> backward compatible by constructing a string on demand, but that will
> really slow things down, unless the whole chain is converted to only
> using the char[] somehow.

Good point: if your analyzer/tokenizer produces char[] tokens then
your downstream filters would have to accept char[] tokens.

I think on-demand constructing a String (and saving it as termText)
would be an OK solution?  Why would that be slower than having to make
a String in the first place (if we didn't have the char[] API)?  It's
at least graceful degradation.

> - It doesn't look like the indexing code currently pays any attention
> to the char[], right?

It does, in DocumentsWriter.addPosition().

> - What if both the String and char[] are set?  A filter that doesn't
> know better sets the String... this doesn't clear the char[]
> currently, should it?

Currently the char[] wins, but good point: seems like each setter
should null out the other one?

Mike

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