Added simple CascadeSave email for User

spring-data-mongodb/src/main/java/org/baeldung/config/MongoConfig.java

@@ -5,6 +5,7 @@
 
 import org.baeldung.converter.UserWriterConverter;
 import org.baeldung.event.CascadeSaveMongoEventListener;
+import org.baeldung.event.UserCascadeSaveMongoEventListener;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.mongodb.config.AbstractMongoConfiguration;
@@ -36,6 +37,11 @@ public String getMappingBasePackage() {
         return "org.baeldung";
     }
 
+    @Bean
+    public UserCascadeSaveMongoEventListener userCascadingMongoEventListener() {
+        return new UserCascadeSaveMongoEventListener();
+    }
+
     @Bean
     public CascadeSaveMongoEventListener cascadingMongoEventListener() {
         return new CascadeSaveMongoEventListener();

spring-data-mongodb/src/main/java/org/baeldung/event/CascadeCallback.java

@@ -8,10 +8,10 @@
 import org.springframework.util.ReflectionUtils;
 
 public class CascadeCallback implements ReflectionUtils.FieldCallback {
-    
+
     private Object source;
     private MongoOperations mongoOperations;
-    
+
     public CascadeCallback(final Object source, final MongoOperations mongoOperations) {
         this.source = source;
         this.setMongoOperations(mongoOperations);

spring-data-mongodb/src/main/java/org/baeldung/event/CascadeSaveMongoEventListener.java

@@ -6,10 +6,10 @@
 import org.springframework.util.ReflectionUtils;
 
 public class CascadeSaveMongoEventListener extends AbstractMongoEventListener<Object> {
-    
+
     @Autowired
     private MongoOperations mongoOperations;
-  
+
     @Override
     public void onBeforeConvert(final Object source) {
         ReflectionUtils.doWithFields(source.getClass(), new CascadeCallback(source, mongoOperations));

spring-data-mongodb/src/main/java/org/baeldung/event/UserCascadeSaveMongoEventListener.java

@@ -0,0 +1,18 @@
+package org.baeldung.event;
+
+import org.baeldung.model.User;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.mongodb.core.MongoOperations;
+import org.springframework.data.mongodb.core.mapping.event.AbstractMongoEventListener;
+
+public class UserCascadeSaveMongoEventListener extends AbstractMongoEventListener<Object> {
+    @Autowired
+    private MongoOperations mongoOperations;
+
+    @Override
+    public void onBeforeConvert(final Object source) {
+        if (source instanceof User && ((User) source).getEmailAddress() != null) {
+            mongoOperations.save(((User) source).getEmailAddress());
+        }
+    }
+}