[rules-users] Better ways to write left hand sides

Greetings fellow Droolers, I've just begun using Drools and am very happy with it so far as it seems to be a great fit for what we want to do. My left hand sides are not quite beautiful enough, however, and I wondered if anyone could suggest improvements. 1) One of my facts' properties is a set of strings. The goal is to "grep" them for some search string. The most convenient syntax I've come up with so far is to give the fact a method anyTextContains which loops over the set and calls contains(searchString) on each member, and then use fact: Fact() eval(fact.anyTextContains("searchString")) in my LHS. It's compact enough, but I wondered whether it could be done without a custom method or eval. "from" seems not to be a possibility since the collection is of strings, not objects. Any suggestions? 2) Another of my facts' properties, "attributes", is a Map of Map of String. Unfortunately the second level of keys is sparse. If the attribute I want is present, Fact(attributes.KeyOne.KeyTwo == 42) looks and works great. If KeyTwo is absent, however, I get org.drools.RuntimeDroolsException: Exception executing predicate attributes.KeyOne.KeyTwo == 42 [...] Caused by: [Error: unable to resolve method: java.util.HashMap.KeyTwo() [arglength=0]] [Near : {... Unknown ....}] The best syntax I've found which is null-safe is Fact(attributes.KeyOne["KeyTwo"] == 42) which works but hurts the eyes somewhat. I'm not clear whether MVEL-style null-safe traversal should work here; my experiments suggest it does not. Again, any suggestions? Thanks, -- | Dave Schweisguth http://schweisguth.org/~dave/ | | Home: dave at schweisguth.org Work: http://www.nileguide.com/ | | For compliance with the NJ Right to Know Act: Contents partially unknown |