Drools- how to find out which all rules were matched?

Question

I\'ve one .DRL file which has say 10 rules. Once I insert a fact, some rules may be matched- how do I find out which rules were matched programmatically?

Answer 1

Steve's answer is solid, but the major changes brought in drools 6 make the code obsolete. I am posting below a rewrite of Steve's code which takes into account the new api:

package your.preferred.package;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.drools.core.event.DefaultAgendaEventListener;
import org.kie.api.definition.rule.Rule;
import org.kie.api.event.rule.AfterMatchFiredEvent;
import org.kie.api.runtime.rule.Match;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A listener that will track all rule firings in a session.
 * 
 * @author Stephen Masters, Isaac Martin
 */
public class TrackingAgendaEventListener extends DefaultAgendaEventListener  {

    private static Logger log = LoggerFactory.getLogger(TrackingAgendaEventListener.class);

    private List matchList = new ArrayList();

    @Override
    public void afterMatchFired(AfterMatchFiredEvent event) {
        Rule rule = event.getMatch().getRule();

        String ruleName = rule.getName();
        Map ruleMetaDataMap = rule.getMetaData();

        matchList.add(event.getMatch());
        StringBuilder sb = new StringBuilder("Rule fired: " + ruleName);

        if (ruleMetaDataMap.size() > 0) {
            sb.append("\n  With [" + ruleMetaDataMap.size() + "] meta-data:");
            for (String key : ruleMetaDataMap.keySet()) {
                sb.append("\n    key=" + key + ", value="
                        + ruleMetaDataMap.get(key));
            }
        }

        log.debug(sb.toString());
    }

    public boolean isRuleFired(String ruleName) {
        for (Match a : matchList) {
            if (a.getRule().getName().equals(ruleName)) {
                return true;
            }
        }
        return false;
    }

    public void reset() {
        matchList.clear();
    }

    public final List getMatchList() {
        return matchList;
    }

    public String matchsToString() {
        if (matchList.size() == 0) {
            return "No matchs occurred.";
        } else {
            StringBuilder sb = new StringBuilder("Matchs: ");
            for (Match match : matchList) {
                sb.append("\n  rule: ").append(match.getRule().getName());
            }
            return sb.toString();
        }
    }

}