Question regarding the rule engine about rules HOT 3 CLOSED

Hi @richiesgr ,

For your problem, I would do something like this:

1. add rules to engine
2. for each input, run it against the engine to retrieve the matching rules.
3. map each matching rule to a score
4. sum the scores - that is the result for a single input
5. repeat 2-4 for each input
6. take the input which had the best result.

Code might look something like this:

static final Map<Rule, Integer> SCORES = new HashMap<>();
SCORES.put(rule1, 30);
SCORES.put(rule2, 50);
//etc...

int bestScore = Integer.MINIMUM;
Input bestInput = null;
for(Input i : inputs){
    List<Rule> matchingRules = engine.getMatchingRules(i);
    int score = matchingRules.toStream().map(r -> SCORES.get(r).sum();
    if(score > bestScore){
        bestScore = score;
        bestInput = i;
    }
}

//now use bestInput...

Would that satisfy your requirements?

from rules.

Of course it seems to be ok

my first question : it is not heavy to process like this ? I want to use it in low latency application based on Akka
Second question: is it thread safe at the engine level and MEVL itself? ( do I need to instanciate each time a new engine ?)

Thanks

from rules.

See DefaultEngineTest.testMultithreadingAndPerformance() (https://github.com/maxant/rules/blob/master/rules/src/test/java/ch/maxant/rules/blackbox/DefaultEngineTest.java) => yes it is threadsafe and fast using MVEL. You do NOT need to instantiate several engines - just create one, as in the test.

from rules.