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From Alfred Nathaniel <anathan...@apache.org>
Subject Re: WildcardMatcherHelper caching issue
Date Sat, 06 Jan 2007 00:03:23 GMT
On Fri, 2007-01-05 at 13:45 +0100, Bruno Dumon wrote:
> Hi,
> 
> I noticed the new WildcardMatcherHelper class holds an internal static
> map for caching. In the older solution, it was up to the caller to cache
> the compiled pattern (similar to how regexp libraries work). This had
> the advantage that the caller itself can decide whether the pattern
> should be cached. It also avoids a potential memory leak if this code is
> used to evaluate always-changing patterns, and avoids the need to do
> hashmap lookups.
> 
> So I'm wondering if anyone would mind if I change it back so that caller
> caches the pattern?
> 
> Thanks for any input.

The integrated cache is a convenience for the many client who repeated
match the same pattern and gain performance without having to code their
own cache management.

If you have an application where you will be matching a lot of one-shot
patterns, you could add

   public static Map match(String pat, String str, Map cache)

which can be called with a null Map to by-pass caching.  The old
signature then becomes simply

   public static Map match(String pat, String str) {
       return match(pat, str, cache);
   }

The built-in cache could also use a WeakHashMap to avoid ever-increasing
memory consumption.

Cheers, Alfred.


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