BAEL-2435 Switch domain around

Change the domain from 'Messages' to 'Order' as that domain is better
suited for an example project like this. The Query Model would be better
 suited to revolve around the OrderedProducts rather than just printing
 out a line of text. To that end, add a OrderedProduct model with the
 OrderStatus, which is updated in the (renamed)
 OrderedProductsEventHandler upon all the events

axon/src/main/java/com/baeldung/axon/coreapi/queries/OrderStatus.java

@@ -0,0 +1,7 @@
+package com.baeldung.axon.coreapi.queries;
+
+public enum OrderStatus {
+
+    PLACED, CONFIRMED, SHIPPED
+
+}

axon/src/main/java/com/baeldung/axon/coreapi/queries/OrderedProduct.java

@@ -0,0 +1,55 @@
+package com.baeldung.axon.coreapi.queries;
+
+import java.util.Objects;
+
+public class OrderedProduct {
+
+    private final String orderId;
+    private final String product;
+    private OrderStatus orderStatus;
+
+    public OrderedProduct(String orderId, String product) {
+        this.orderId = orderId;
+        this.product = product;
+        orderStatus = OrderStatus.PLACED;
+    }
+
+    public String getOrderId() {
+        return orderId;
+    }
+
+    public String getProduct() {
+        return product;
+    }
+
+    public OrderStatus getOrderStatus() {
+        return orderStatus;
+    }
+
+    public void setOrderConfirmed() {
+        this.orderStatus = OrderStatus.CONFIRMED;
+    }
+
+    public void setOrderShipped() {
+        this.orderStatus = OrderStatus.SHIPPED;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(orderId, product, orderStatus);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final OrderedProduct other = (OrderedProduct) obj;
+        return Objects.equals(this.orderId, other.orderId)
+                && Objects.equals(this.product, other.product)
+                && Objects.equals(this.orderStatus, other.orderStatus);
+    }
+}

axon/src/main/java/com/baeldung/axon/querymodel/MessagesEventHandler.java

@@ -1,21 +0,0 @@
-package com.baeldung.axon.querymodel;
-
-import org.axonframework.eventhandling.EventHandler;
-import org.springframework.stereotype.Service;
-
-import com.baeldung.axon.coreapi.events.MessageCreatedEvent;
-import com.baeldung.axon.coreapi.events.MessageReadEvent;
-
-@Service
-public class MessagesEventHandler {
-
-    @EventHandler
-    public void handle(MessageCreatedEvent event) {
-        System.out.println("Message received: " + event.getText() + " (" + event.getId() + ")");
-    }
-
-    @EventHandler
-    public void handle(MessageReadEvent event) {
-        System.out.println("Message read: " + event.getId());
-    }
-}

axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java

@@ -0,0 +1,42 @@
+package com.baeldung.axon.querymodel;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.axonframework.eventhandling.EventHandler;
+import org.springframework.stereotype.Service;
+
+import com.baeldung.axon.coreapi.queries.OrderedProduct;
+import com.baeldung.axon.coreapi.events.OrderConfirmedEvent;
+import com.baeldung.axon.coreapi.events.OrderPlacedEvent;
+import com.baeldung.axon.coreapi.events.OrderShippedEvent;
+
+@Service
+public class OrderedProductsEventHandler {
+
+    private final Map<String, OrderedProduct> orderedProducts = new HashMap<>();
+
+    @EventHandler
+    public void on(OrderPlacedEvent event) {
+        String orderId = event.getOrderId();
+        orderedProducts.put(orderId, new OrderedProduct(orderId, event.getProduct()));
+
+    }
+
+    @EventHandler
+    public void on(OrderShippedEvent event) {
+        orderedProducts.computeIfPresent(event.getOrderId(), (orderId, orderedProduct) -> {
+            orderedProduct.setOrderShipped();
+            return orderedProduct;
+        });
+    }
+
+    @EventHandler
+    public void on(OrderConfirmedEvent event) {
+        orderedProducts.computeIfPresent(event.getOrderId(), (orderId, orderedProduct) -> {
+            orderedProduct.setOrderConfirmed();
+            return orderedProduct;
+        });
+    }
+
+}