#BAEL-18410 add code sample for reduce with complex objects

core-java-modules/core-java-8/src/main/java/com/baeldung/streamreduce/entities/Rating.java

@@ -0,0 +1,39 @@
+package com.baeldung.streamreduce.entities;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Rating {
+
+    double points;
+    List<Review> reviews = new ArrayList<>();
+
+    public Rating() {}
+
+    public void add(Review review) {
+        reviews.add(review);
+        computeRating();
+    }
+
+    private double computeRating() {
+        double totalPoints = reviews.stream().map(Review::getPoints).reduce(0, Integer::sum);
+        this.points = totalPoints / reviews.size();
+        return this.points;
+    }
+
+    public static Rating average(Rating r1, Rating r2) {
+        Rating combined = new Rating();
+        combined.reviews = new ArrayList<>(r1.reviews);
+        combined.reviews.addAll(r2.reviews);
+        combined.computeRating();
+        return combined;
+    }
+
+    public double getPoints() {
+        return points;
+    }
+
+    public List<Review> getReviews() {
+        return reviews;
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/streamreduce/entities/Review.java

@@ -0,0 +1,28 @@
+package com.baeldung.streamreduce.entities;
+
+public class Review {
+
+    int points;
+    String review;
+
+    public Review(int points, String review) {
+        this.points = points;
+        this.review = review;
+    }
+
+    public int getPoints() {
+        return points;
+    }
+
+    public void setPoints(int points) {
+        this.points = points;
+    }
+
+    public String getReview() {
+        return review;
+    }
+
+    public void setReview(String review) {
+        this.review = review;
+    }
+}

core-java-modules/core-java-8/src/main/java/com/baeldung/streamreduce/entities/User.java

@@ -4,6 +4,7 @@ public class User {
 
     private final String name;
     private final int age;
+    private final Rating rating = new Rating();
 
     public User(String name, int age) {
         this.name = name;
@@ -17,7 +18,11 @@ public class User {
     public int getAge() {
         return age;
     }
-    
+
+    public Rating getRating() {
+        return rating;
+    }
+
     @Override
     public String toString() {
         return "User{" + "name=" + name + ", age=" + age + '}';