diff --git a/axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java b/axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java
index a37f0111ed..3efd81fd37 100644
--- a/axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java
+++ b/axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java
@@ -1,20 +1,23 @@
 package com.baeldung.axon.querymodel;
 
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
+import com.baeldung.axon.coreapi.events.OrderConfirmedEvent;
+import com.baeldung.axon.coreapi.events.OrderPlacedEvent;
+import com.baeldung.axon.coreapi.events.OrderShippedEvent;
+import com.baeldung.axon.coreapi.events.ProductAddedEvent;
+import com.baeldung.axon.coreapi.events.ProductCountDecrementedEvent;
+import com.baeldung.axon.coreapi.events.ProductCountIncrementedEvent;
+import com.baeldung.axon.coreapi.events.ProductRemovedEvent;
+import com.baeldung.axon.coreapi.queries.FindAllOrderedProductsQuery;
+import com.baeldung.axon.coreapi.queries.OrderedProduct;
 import org.axonframework.config.ProcessingGroup;
 import org.axonframework.eventhandling.EventHandler;
 import org.axonframework.queryhandling.QueryHandler;
 import org.springframework.stereotype.Service;
 
-import com.baeldung.axon.coreapi.events.OrderConfirmedEvent;
-import com.baeldung.axon.coreapi.events.OrderPlacedEvent;
-import com.baeldung.axon.coreapi.events.OrderShippedEvent;
-import com.baeldung.axon.coreapi.queries.FindAllOrderedProductsQuery;
-import com.baeldung.axon.coreapi.queries.OrderedProduct;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 
 @Service
 @ProcessingGroup("ordered-products")
@@ -25,7 +28,39 @@ public class OrderedProductsEventHandler {
     @EventHandler
     public void on(OrderPlacedEvent event) {
         String orderId = event.getOrderId();
-        orderedProducts.put(orderId, new OrderedProduct(orderId, event.getProduct()));
+        orderedProducts.put(orderId, new OrderedProduct(orderId));
+    }
+
+    @EventHandler
+    public void on(ProductAddedEvent event) {
+        orderedProducts.computeIfPresent(event.getOrderId(), (orderId, orderedProduct) -> {
+            orderedProduct.addProduct(event.getProductId());
+            return orderedProduct;
+        });
+    }
+
+    @EventHandler
+    public void on(ProductCountIncrementedEvent event) {
+        orderedProducts.computeIfPresent(event.getOrderId(), (orderId, orderedProduct) -> {
+            orderedProduct.incrementProductInstance(event.getProductId());
+            return orderedProduct;
+        });
+    }
+
+    @EventHandler
+    public void on(ProductCountDecrementedEvent event) {
+        orderedProducts.computeIfPresent(event.getOrderId(), (orderId, orderedProduct) -> {
+            orderedProduct.decrementProductInstance(event.getProductId());
+            return orderedProduct;
+        });
+    }
+
+    @EventHandler
+    public void on(ProductRemovedEvent event) {
+        orderedProducts.computeIfPresent(event.getOrderId(), (orderId, orderedProduct) -> {
+            orderedProduct.removeProduct(event.getProductId());
+            return orderedProduct;
+        });
     }
 
     @EventHandler
@@ -48,5 +83,4 @@ public class OrderedProductsEventHandler {
     public List<OrderedProduct> handle(FindAllOrderedProductsQuery query) {
         return new ArrayList<>(orderedProducts.values());
     }
-
 }
\ No newline at end of file