FINERACT-1694: Reworked bulk external events

fineract-provider/src/main/java/org/apache/fineract/infrastructure/event/business/service/BusinessEventNotifierService.java

@@ -47,4 +47,7 @@ public interface BusinessEventNotifierService {
      */
     <T extends BusinessEvent<?>> void addPostBusinessEventListener(Class<T> eventType, BusinessEventListener<T> listener);
 
+    void startExternalEventRecording();
+
+    void stopExternalEventRecording();
 }

fineract-provider/src/main/java/org/apache/fineract/infrastructure/event/business/service/BusinessEventNotifierServiceImpl.java

@@ -26,6 +26,7 @@ import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.fineract.infrastructure.core.config.FineractProperties;
 import org.apache.fineract.infrastructure.event.business.BusinessEventListener;
+import org.apache.fineract.infrastructure.event.business.domain.BulkBusinessEvent;
 import org.apache.fineract.infrastructure.event.business.domain.BusinessEvent;
 import org.apache.fineract.infrastructure.event.external.service.ExternalEventService;
 import org.springframework.beans.factory.InitializingBean;
@@ -40,6 +41,9 @@ public class BusinessEventNotifierServiceImpl implements BusinessEventNotifierSe
     private final Map<Class, List<BusinessEventListener>> preListeners = new HashMap<>();
     private final Map<Class, List<BusinessEventListener>> postListeners = new HashMap<>();
 
+    private final ThreadLocal<Boolean> eventRecordingEnabled = ThreadLocal.withInitial(() -> false);
+    private final ThreadLocal<List<BusinessEvent<?>>> recordedEvents = ThreadLocal.withInitial(ArrayList::new);
+
     private final ExternalEventService externalEventService;
     private final FineractProperties fineractProperties;
 
@@ -54,6 +58,7 @@ public class BusinessEventNotifierServiceImpl implements BusinessEventNotifierSe
 
     @Override
     public void notifyPreBusinessEvent(BusinessEvent<?> businessEvent) {
+        throwExceptionIfBulkEvent(businessEvent);
         List<BusinessEventListener> businessEventListeners = preListeners.get(businessEvent.getClass());
         if (businessEventListeners != null) {
             for (BusinessEventListener eventListener : businessEventListeners) {
@@ -74,6 +79,7 @@ public class BusinessEventNotifierServiceImpl implements BusinessEventNotifierSe
 
     @Override
     public void notifyPostBusinessEvent(BusinessEvent<?> businessEvent) {
+        throwExceptionIfBulkEvent(businessEvent);
         List<BusinessEventListener> businessEventListeners = postListeners.get(businessEvent.getClass());
         if (businessEventListeners != null) {
             for (BusinessEventListener eventListener : businessEventListeners) {
@@ -82,14 +88,14 @@ public class BusinessEventNotifierServiceImpl implements BusinessEventNotifierSe
         }
         if (isExternalEventPostingEnabled()) {
             // we only want to create external events for operations that were successful, hence the post listener
-            externalEventService.postEvent(businessEvent);
+            if (isExternalEventRecordingEnabled()) {
+                recordedEvents.get().add(businessEvent);
+            } else {
+                externalEventService.postEvent(businessEvent);
+            }
         }
     }
 
-    private boolean isExternalEventPostingEnabled() {
-        return fineractProperties.getEvents().getExternal().isEnabled();
-    }
-
     @Override
     public <T extends BusinessEvent<?>> void addPostBusinessEventListener(Class<T> eventType, BusinessEventListener<T> listener) {
         List<BusinessEventListener> businessEventListeners = postListeners.get(eventType);
@@ -99,4 +105,37 @@ public class BusinessEventNotifierServiceImpl implements BusinessEventNotifierSe
         }
         businessEventListeners.add(listener);
     }
+
+    private boolean isExternalEventRecordingEnabled() {
+        return eventRecordingEnabled.get();
+    }
+
+    private boolean isExternalEventPostingEnabled() {
+        return fineractProperties.getEvents().getExternal().isEnabled();
+    }
+
+    private void throwExceptionIfBulkEvent(BusinessEvent<?> businessEvent) {
+        if (businessEvent instanceof BulkBusinessEvent) {
+            throw new IllegalArgumentException("BulkBusinessEvent cannot be raised directly");
+        }
+    }
+
+    @Override
+    public void startExternalEventRecording() {
+        eventRecordingEnabled.set(true);
+    }
+
+    @Override
+    public void stopExternalEventRecording() {
+        eventRecordingEnabled.set(false);
+        try {
+            List<BusinessEvent<?>> recordedBusinessEvents = recordedEvents.get();
+            if (isExternalEventPostingEnabled()) {
+                log.debug("Posting the BulkBusinessEvent for the recorded {} events", recordedBusinessEvents.size());
+                externalEventService.postEvent(new BulkBusinessEvent(recordedBusinessEvents));
+            }
+        } finally {
+            recordedEvents.remove();
+        }
+    }
 }

fineract-provider/src/main/java/org/apache/fineract/infrastructure/event/external/service/DelayedExternalEventService.java

@@ -1,64 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. The ASF licenses this file
- * to you 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.apache.fineract.infrastructure.event.external.service;
-
-import java.util.ArrayList;
-import java.util.List;
-import lombok.RequiredArgsConstructor;
-import org.apache.fineract.infrastructure.event.business.domain.BulkBusinessEvent;
-import org.apache.fineract.infrastructure.event.business.domain.BusinessEvent;
-import org.springframework.stereotype.Service;
-
-@Service
-@RequiredArgsConstructor
-public class DelayedExternalEventService {
-
-    private final ThreadLocal<List<BusinessEvent<?>>> localEventStorage = ThreadLocal.withInitial(ArrayList::new);
-
-    private final ExternalEventService delegate;
-
-    public <T> void enqueueEvent(BusinessEvent<T> event) {
-        if (event == null) {
-            throw new IllegalArgumentException("event cannot be null");
-        }
-
-        localEventStorage.get().add(event);
-    }
-
-    public boolean hasEnqueuedEvents() {
-        return !localEventStorage.get().isEmpty();
-    }
-
-    public void clearEnqueuedEvents() {
-        localEventStorage.get().clear();
-    }
-
-    public List<BusinessEvent<?>> getEnqueuedEvents() {
-        return List.copyOf(localEventStorage.get());
-    }
-
-    public void postEnqueuedEvents() {
-        List<BusinessEvent<?>> enqueuedEvents = localEventStorage.get();
-        if (enqueuedEvents.isEmpty()) {
-            throw new IllegalStateException("No events have been enqueued");
-        }
-
-        delegate.postEvent(new BulkBusinessEvent(enqueuedEvents));
-    }
-}