Bael 7912: Find list of matched rules in Drools

drools/src/main/java/com/baeldung/drools/config/DroolsBeanFactory.java

@@ -7,7 +7,6 @@
 import org.kie.api.KieServices;
 import org.kie.api.builder.KieBuilder;
 import org.kie.api.builder.KieFileSystem;
-import org.kie.api.builder.KieModule;
 import org.kie.api.builder.KieRepository;
 import org.kie.api.builder.ReleaseId;
 import org.kie.api.io.Resource;
@@ -25,7 +24,9 @@ public class DroolsBeanFactory {
 
     private KieFileSystem getKieFileSystem() {
         KieFileSystem kieFileSystem = kieServices.newKieFileSystem();
-        List<String> rules = Arrays.asList("com/baeldung/drools/rules/BackwardChaining.drl", "com/baeldung/drools/rules/SuggestApplicant.drl", "com/baeldung/drools/rules/Product_rules.drl.xls");
+        List<String> rules = Arrays.asList("com/baeldung/drools/rules/BackwardChaining.drl", "com/baeldung/drools/rules/SuggestApplicant.drl",
+          "com/baeldung/drools/rules/Product_rules.drl.xls", "com/baeldung/drools/rules/eligibility_rules_event.drl",
+          "com/baeldung/drools/rules/eligibility_rules_context.drl");
         for (String rule : rules) {
             kieFileSystem.write(ResourceFactory.newClassPathResource(rule));
         }

drools/src/main/java/com/baeldung/drools/matched_rules/Person.java

@@ -0,0 +1,49 @@
+package com.baeldung.drools.matched_rules;
+
+public class Person {
+    private String name;
+    private int age;
+    private boolean eligibleToVote;
+    private boolean priorityVoter;
+
+
+    // Constructors
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+        this.eligibleToVote = false;
+        this.priorityVoter = false;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public boolean isEligibleToVote() {
+        return eligibleToVote;
+    }
+
+    public void setEligibleToVote(boolean eligibleToVote) {
+        this.eligibleToVote = eligibleToVote;
+    }
+
+    public boolean isPriorityVoter() {
+        return priorityVoter;
+    }
+
+    public void setPriorityVoter(boolean priorityVoter) {
+        this.priorityVoter = priorityVoter;
+    }
+}

drools/src/main/java/com/baeldung/drools/matched_rules/RuleTracker.java

@@ -0,0 +1,17 @@
+package com.baeldung.drools.matched_rules;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class RuleTracker {
+
+    private final List<String> firedRules = new ArrayList<>();
+
+    public void add(String ruleName) {
+        firedRules.add(ruleName);
+    }
+
+    public List<String> getFiredRules() {
+        return firedRules;
+    }
+}

drools/src/main/java/com/baeldung/drools/matched_rules/RuleUtils.java

@@ -0,0 +1,11 @@
+package com.baeldung.drools.matched_rules;
+
+import org.kie.api.runtime.rule.RuleContext;
+
+public class RuleUtils {
+
+    public static void track(RuleContext ctx, RuleTracker tracker) {
+        String ruleName = ctx.getRule().getName();
+        tracker.add(ruleName);
+    }
+}

drools/src/main/java/com/baeldung/drools/matched_rules/TrackingAgendaEventListener.java

@@ -0,0 +1,26 @@
+package com.baeldung.drools.matched_rules;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.kie.api.event.rule.AfterMatchFiredEvent;
+import org.kie.api.event.rule.DefaultAgendaEventListener;
+import org.kie.api.runtime.rule.Match;
+
+public class TrackingAgendaEventListener extends DefaultAgendaEventListener {
+    private final List<Match> matchList = new ArrayList<>();
+
+    @Override
+    public void afterMatchFired(AfterMatchFiredEvent event) {
+        matchList.add(event.getMatch());
+    }
+
+    public List<String> getFiredRuleNames() {
+        List<String> names = new ArrayList<>();
+        for (Match m : matchList) {
+            names.add(m.getRule().getName());
+        }
+        return names;
+    }
+
+}

drools/src/main/resources/com/baeldung/drools/rules/eligibility_rules_context.drl

@@ -0,0 +1,25 @@
+package com.baeldung.drools.rules
+
+import com.baeldung.drools.matched_rules.Person;
+import com.baeldung.drools.matched_rules.RuleTracker;
+import static com.baeldung.drools.matched_rules.RuleUtils.track;
+
+rule "Check Voting Eligibility"
+    when
+        $person : Person(age >= 18)
+        $tracker : RuleTracker()
+    then
+        track(drools, $tracker);
+        $person.setEligibleToVote(true);
+        update($person);
+end
+
+rule "Senior Priority Voting"
+    when
+        $person : Person(age >= 65)
+        $tracker : RuleTracker()
+    then
+        track(drools, $tracker);
+        $person.setPriorityVoter(true);
+        update($person);
+end

drools/src/main/resources/com/baeldung/drools/rules/eligibility_rules_event.drl

@@ -0,0 +1,19 @@
+package com.baeldung.drools.rules
+
+import com.baeldung.drools.matched_rules.Person;
+
+rule "Check Voting Eligibility Event"
+    when
+        $person : Person(age >= 18)
+    then
+        $person.setEligibleToVote(true);
+        update($person);
+end
+
+rule "Senior Priority Voting Event"
+    when
+        $person : Person(age >= 65)
+    then
+        $person.setPriorityVoter(true);
+        update($person);
+end

drools/src/test/java/com/baeldung/drools/matched_rules/MatchedRulesUnitTest.java

@@ -0,0 +1,65 @@
+package com.baeldung.drools.matched_rules;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.kie.api.runtime.KieSession;
+
+import com.baeldung.drools.config.DroolsBeanFactory;
+
+public class MatchedRulesUnitTest {
+
+    private KieSession kieSession;
+
+    @BeforeEach
+    public void before() {
+        kieSession = new DroolsBeanFactory().getKieSession();
+    }
+
+    @Test
+    public void givenPerson_whenListenerAttached_thenRuleIsTracked() {
+        // Given
+        Person person = new Person("Bob", 65);
+
+        TrackingAgendaEventListener listener = new TrackingAgendaEventListener();
+        kieSession.addEventListener(listener);
+
+        // When
+        kieSession.insert(person);
+        kieSession.fireAllRules();
+        kieSession.dispose();
+
+        // Then
+        assertFalse(listener.getFiredRuleNames().isEmpty());
+        assertTrue(listener.getFiredRuleNames().contains("Check Voting Eligibility Event"));
+        assertTrue(listener.getFiredRuleNames().contains("Senior Priority Voting Event"));
+    }
+
+    @Test
+    public void givenPerson_whenRulesFire_thenContextTracksFiredRules() {
+        // Given
+        Person person = new Person("John", 70);
+        RuleTracker tracker = new RuleTracker();
+
+        // When
+        kieSession.insert(person);
+        kieSession.insert(tracker);
+
+        kieSession.fireAllRules();
+        kieSession.dispose();
+
+        // Then
+        List<String> fired = tracker.getFiredRules();
+
+        assertTrue(fired.contains("Check Voting Eligibility"));
+        assertTrue(fired.contains("Senior Priority Voting"));
+
+        assertTrue(person.isEligibleToVote());
+        assertTrue(person.isPriorityVoter());
+    }
+
+}