[DROOLS-7416] Invalidate RuleUnit

drools-ruleunits/drools-ruleunits-api/src/main/java/org/drools/ruleunits/api/RuleUnitProvider.java

@@ -61,6 +61,12 @@ default <T extends RuleUnitData> RuleUnitInstance<T> createRuleUnitInstance(T ru
         return ruleUnit.createInstance(ruleUnitData, ruleConfig);
     }
 
+    /**
+     * Invalidates all {@link RuleUnit}s generated from the given class.
+     * @return The number of invalidated ruleunits.
+     */
+    <T extends RuleUnitData> int invalidateRuleUnits(Class<T> ruleUnitDataClass);
+
     /**
      * Creates a new RuleConfig instance.
      */

drools-ruleunits/drools-ruleunits-dsl/src/test/java/org/drools/ruleunits/dsl/DynamicHelloWorldUnit.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2023 Red Hat, Inc. and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.drools.ruleunits.dsl;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.drools.ruleunits.api.DataSource;
+import org.drools.ruleunits.api.DataStore;
+import org.drools.ruleunits.impl.NamedRuleUnitData;
+
+import static org.drools.model.Index.ConstraintType.EQUAL;
+
+public class DynamicHelloWorldUnit implements RuleUnitDefinition {
+
+    private final DataStore<String> strings;
+
+    private final List<String> results = new ArrayList<>();
+
+    private final String expectedMessage; // this is the dynamic part
+
+    public DynamicHelloWorldUnit(String expectedMessage) {
+        this.strings = DataSource.createStore();
+        this.expectedMessage = expectedMessage;
+    }
+
+    public DataStore<String> getStrings() {
+        return strings;
+    }
+
+
+    public List<String> getResults() {
+        return results;
+    }
+
+    @Override
+    public void defineRules(RulesFactory rulesFactory) {
+        // /strings[ this == expectedMessage ]
+        rulesFactory.rule()
+                    .on(strings)
+                    .filter(EQUAL, expectedMessage) // when no extractor is provided "this" is implicit
+                    .execute(results, r -> r.add("it worked!")); // the consequence can ignore the matched facts
+    }
+}

drools-ruleunits/drools-ruleunits-dsl/src/test/java/org/drools/ruleunits/dsl/RuleUnitRebuildTest.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2023 Red Hat, Inc. and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.drools.ruleunits.dsl;
+
+import org.drools.ruleunits.api.RuleUnitInstance;
+import org.drools.ruleunits.api.RuleUnitProvider;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class RuleUnitRebuildTest {
+
+    @Test
+    void dynamicHelloWorld() {
+        DynamicHelloWorldUnit unit = new DynamicHelloWorldUnit("Hello World");
+        unit.getStrings().add("Hello World");
+
+        try (RuleUnitInstance<DynamicHelloWorldUnit> unitInstance = RuleUnitProvider.get().createRuleUnitInstance(unit)) {
+            assertThat(unitInstance.fire()).isEqualTo(1);
+            assertThat(unit.getResults()).containsExactly("it worked!");
+        }
+
+        int invalidated = RuleUnitProvider.get().invalidateRuleUnits(DynamicHelloWorldUnit.class);
+        assertThat(invalidated).as("Invalidate 1 rule unit").isEqualTo(1);
+
+        DynamicHelloWorldUnit newUnit = new DynamicHelloWorldUnit("Goodbye World");
+        newUnit.getStrings().add("Hello World");
+
+        try (RuleUnitInstance<DynamicHelloWorldUnit> newUnitInstance = RuleUnitProvider.get().createRuleUnitInstance(newUnit)) {
+            assertThat(newUnitInstance.fire()).isZero();
+            assertThat(newUnit.getResults()).isEmpty();
+
+            newUnit.getStrings().add("Goodbye World");
+            assertThat(newUnitInstance.fire()).isEqualTo(1);
+            assertThat(newUnit.getResults()).containsExactly("it worked!");
+        }
+    }
+}

drools-ruleunits/drools-ruleunits-impl/src/main/java/org/drools/ruleunits/impl/RuleUnitProviderImpl.java

@@ -233,4 +233,10 @@ public RuleConfig newRuleConfig() {
         return new RuleConfigImpl();
     }
 
+    @Override
+    public <T extends RuleUnitData> int invalidateRuleUnits(Class<T> ruleUnitDataClass) {
+        String ruleUnitName = getRuleUnitName(ruleUnitDataClass);
+        RuleUnit remove = ruleUnitMap.remove(ruleUnitName);
+        return remove == null ? 0 : 1;
+    }
 }