[AFP-37] ✨ getting item data (Items ordered) from each order [@dbhuller]

src/main/java/com/afp/ordermanagement/controller/OrderController.java

 package com.afp.ordermanagement.controller;
 
+import com.afp.ordermanagement.model.Item;
 import com.afp.ordermanagement.model.Order;
 import com.afp.ordermanagement.reactivekafkaservice.Sender;
 import com.afp.ordermanagement.service.OrderService;
@@ -10,6 +11,8 @@ import org.springframework.web.bind.annotation.*;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import java.util.List;
+
 @RestController
 @RequestMapping("/api")
 @CrossOrigin
@@ -60,5 +63,9 @@ public class OrderController {
                 .defaultIfEmpty(ResponseEntity.notFound().build());
     }
 
+    @GetMapping("/items")
+    public Mono<List<Item>> getItems() {
+        return orderService.getItems();
+    }
 
 }

src/main/java/com/afp/ordermanagement/service/OrderService.java

 package com.afp.ordermanagement.service;
 
+import com.afp.ordermanagement.model.Item;
 import com.afp.ordermanagement.model.Order;
 import com.afp.ordermanagement.model.OrderStatus;
 import com.afp.ordermanagement.repository.OrderRepository;
@@ -8,6 +9,9 @@ import org.springframework.stereotype.Service;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
+import java.util.List;
+import java.util.stream.Collectors;
+
 @Service
 public class OrderService {
 
@@ -50,4 +54,19 @@ public class OrderService {
                     return orderRepository.save(existingOrder);
                 });
     }
+
+    public Mono<List<Item>> getItems() {
+        Flux<Order> orderFlux = orderRepository.findAll();
+        Mono<List<Item>> itemsMono = orderFlux.collectList().map(ordersList -> {
+            List<List<Item>> itemList =
+                    ordersList.stream()
+                            .filter(order -> order.getOrderItems() != null)
+                            .map(order -> order.getOrderItems())
+                            .collect(
+                            Collectors.toList());
+            List<Item> items = itemList.stream().flatMap(List::stream).collect(Collectors.toList());
+            return items;
+        });
+        return itemsMono;
+    }
 }