Re: [rules-users] Re: Help with MatchesEvaluatorsDefinition that caches compiled regular expression patterns

Edson Tirelli <tirelli <at> post.com> writes: > > > Jared, Your idea is actually interesting. Although, we would need to take care of a few edge scenarios:* The actual evaluator instance is supposed to be a "fly weight" implementation, and as so, it might be used by multiple threads. So, first thing, the cache map implementation must be thread safe. * We had problems in the past when using static caches like that in JEE/Spring/OSGi environments where you have multiple modules being loaded by different classloaders etc. So, I think best would be to have a non-static map for each: the StringMatchesEvaluator and the StringNotMatchesEvaluator inner classes.* We need a way to clean up the cache for no-longer used expressions. Easiest way would probably be to use an LRU map as cache. The size of the cache would probably have to be a configuration on the KnowledgeBaseConfiguration, with a given default value. This would avoid memory leaks. Wanna try providing a patch for that? Thanks, Edson 2009/5/4 Jared Davis <sunray <at> davisprogramming.com>I need some help placing a cache of compiled regular expressions using the > MatchesEvaluatorsDefinition as a starting point. > Just for a test I placed a static map in the class: > static Map<String,Pattern> uglyHack = new HashMap<String,Pattern>(); > Then in each of the evaluators I have different versions of: > Pattern p = uglyHack.get(value2); > if (p == null ) { > p = Pattern.compile(value2); > uglyHack.put(value2, p); > } > Matcher m = p.matcher(value1); > return m.matches(); > instead of > return value1.matches( value2 ); > The time elapsed to inserting objects into the workspace has been cut in half. > .4 seconds -> .2 > Has someone already done this "optimization?" Where should the cache be stored? > _______________________________________________ <snip> Edson, One persons memory leak is another's optimization.<g> I'll give it a shot. Is there a drools preferred thread safe LRUCache implementation? Seems like hours/days could be spent on the cache algorithm. Jared _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users