Merge pull request #15334 from etrandafir93/features/BAEL-7143-virtual_threads_vs_webflux_2

Features/bael 7143 virtual threads vs webflux 2

spring-reactive-modules/pom.xml

@@ -30,6 +30,9 @@
         <module>spring-reactive-exceptions</module>
         <module>spring-reactor</module>
         <module>spring-webflux-amqp</module>
+
+        <!--    the following submodules are commented out as a workaround in order to use java 19+ and SB 3.2.x -->
+        <!--    <module>spring-reactive-performance</module>-->
     </modules>
 
     <build>

spring-reactive-modules/spring-reactive-performance/.gitignore

@@ -0,0 +1,25 @@
+/target/
+!.mvn/wrapper/maven-wrapper.jar
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/build/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/

spring-reactive-modules/spring-reactive-performance/README.md

@@ -0,0 +1,3 @@
+## Spring Reactive Performance
+
+This module contains articles about reactive Spring Boot.

spring-reactive-modules/spring-reactive-performance/pom.xml

@@ -0,0 +1,77 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.spring</groupId>
+    <artifactId>spring-reactive-performance</artifactId>
+    <version>1.0.0-SNAPSHOT</version>
+    <name>spring-reactive-performance</name>
+    <packaging>jar</packaging>
+    <description>Spring Reactive Performance</description>
+
+    <parent>
+        <groupId>com.baeldung.spring.reactive</groupId>
+        <artifactId>spring-reactive-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <!-- Import dependency management from Spring Boot -->
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+                <version>${spring-boot.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-webflux</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-webflux</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-mongodb</artifactId>
+        </dependency>
+
+    </dependencies>
+
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>21</source>
+                    <target>21</target>
+                    <!-- Needed due to a bug with JDK 21, described here: https://issues.apache.org/jira/browse/MCOMPILER-546?page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel&focusedCommentId=17767513 -->
+                    <debug>false</debug>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <argLine>--enable-preview</argLine>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <java.version>21</java.version>
+        <spring-boot.version>3.2.0</spring-boot.version>
+    </properties>
+</project>

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/Application.java

@@ -0,0 +1,13 @@
+package com.baeldung.spring.reactive.performance;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+    
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/KafkaTemplate.java

@@ -0,0 +1,14 @@
+package com.baeldung.spring.reactive.performance;
+
+import java.util.concurrent.CompletableFuture;
+
+public class KafkaTemplate<K, V> {
+
+    // For simplicity in this example and article, an actual Kafka client isn't utilized.
+    // The focus remains on demonstrating the basic principles without the complexities of a full Kafka client setup.
+
+    public CompletableFuture<Void> send(String topic, K key, V value) {
+        System.out.println("Sending message to topic: " + topic + " with value: " + value);
+        return CompletableFuture.completedFuture(null);
+    }
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/ProductAddedToCartEvent.java

@@ -0,0 +1,6 @@
+package com.baeldung.spring.reactive.performance;
+
+import java.math.BigDecimal;
+
+public record ProductAddedToCartEvent(String productId, BigDecimal price, String currency, String cartId) {
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/model/Price.java

@@ -0,0 +1,9 @@
+package com.baeldung.spring.reactive.performance.model;
+
+import java.math.BigDecimal;
+
+public record Price(BigDecimal value, String currency) {
+    public Price applyDiscount(BigDecimal discount) {
+        return new Price(value.subtract(discount), currency);
+    }
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/model/Product.java

@@ -0,0 +1,43 @@
+package com.baeldung.spring.reactive.performance.model;
+
+import java.math.BigDecimal;
+
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+@Document(collation = "products")
+public record Product (
+    @Id
+    String id,
+    String name,
+    BigDecimal basePriceValue,
+    String currency,
+    Category category
+) {
+
+    public Price basePrice() {
+        return new Price(basePriceValue, currency);
+    }
+
+    public enum Category {
+        ELECTRONICS(false),
+        CLOTHING(true),
+        ACCESSORIES(false),
+        GARDENING(false),
+        SPORTS(true);
+
+        private final boolean eligibleForPromotion;
+
+        Category(boolean eligibleForPromotion) {
+            this.eligibleForPromotion = eligibleForPromotion;
+        }
+
+        public boolean isEligibleForDiscount() {
+            return eligibleForPromotion;
+        }
+
+        public boolean notEligibleForPromotion() {
+            return !eligibleForPromotion;
+        }
+    }
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/virtualthreads/DiscountService.java

@@ -0,0 +1,11 @@
+package com.baeldung.spring.reactive.performance.virtualthreads;
+
+import java.math.BigDecimal;
+
+class DiscountService {
+
+    public BigDecimal discountForProduct(String productId) {
+        return BigDecimal.valueOf(10);
+    }
+
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/virtualthreads/ProductRepository.java

@@ -0,0 +1,8 @@
+package com.baeldung.spring.reactive.performance.virtualthreads;
+
+import org.springframework.data.mongodb.repository.MongoRepository;
+
+import com.baeldung.spring.reactive.performance.model.Product;
+
+interface ProductRepository extends MongoRepository<Product, String> {
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/virtualthreads/ProductService.java

@@ -0,0 +1,45 @@
+package com.baeldung.spring.reactive.performance.virtualthreads;
+
+import java.math.BigDecimal;
+
+import com.baeldung.spring.reactive.performance.KafkaTemplate;
+import com.baeldung.spring.reactive.performance.ProductAddedToCartEvent;
+import com.baeldung.spring.reactive.performance.model.Price;
+import com.baeldung.spring.reactive.performance.model.Product;
+
+class ProductService {
+    private final String PRODUCT_ADDED_TO_CART_TOPIC = "product-added-to-cart";
+
+    private final ProductRepository repository;
+    private final DiscountService discountService;
+    private final KafkaTemplate<String, ProductAddedToCartEvent> kafkaTemplate;
+
+    public ProductService(ProductRepository repository, DiscountService discountService) {
+        this.repository = repository;
+        this.discountService = discountService;
+        this.kafkaTemplate = new KafkaTemplate<>();
+    }
+
+    public void addProductToCart(String productId, String cartId) {
+        Thread.startVirtualThread(() -> computePriceAndPublishMessage(productId, cartId));
+    }
+
+    private void computePriceAndPublishMessage(String productId, String cartId) {
+        Product product = repository.findById(productId)
+          .orElseThrow(() -> new IllegalArgumentException("not found!"));
+
+        Price price = computePrice(productId, product);
+
+        var event = new ProductAddedToCartEvent(productId, price.value(), price.currency(), cartId);
+        kafkaTemplate.send(PRODUCT_ADDED_TO_CART_TOPIC, cartId, event);
+    }
+
+    private Price computePrice(String productId, Product product) {
+        if (product.category().isEligibleForDiscount()) {
+            BigDecimal discount = discountService.discountForProduct(productId);
+            return product.basePrice().applyDiscount(discount);
+        }
+        return product.basePrice();
+    }
+
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/webflux/DiscountService.java

@@ -0,0 +1,11 @@
+package com.baeldung.spring.reactive.performance.webflux;
+
+import java.math.BigDecimal;
+
+import reactor.core.publisher.Mono;
+
+class DiscountService {
+    public Mono<BigDecimal> discountForProduct(String productId) {
+        return Mono.just(BigDecimal.valueOf(10));
+    }
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/webflux/ProductRepository.java

@@ -0,0 +1,8 @@
+package com.baeldung.spring.reactive.performance.webflux;
+
+import org.springframework.data.mongodb.repository.ReactiveMongoRepository;
+
+import com.baeldung.spring.reactive.performance.model.Product;
+
+interface ProductRepository extends ReactiveMongoRepository<Product, String> {
+}

spring-reactive-modules/spring-reactive-performance/src/main/java/com/baeldung/spring/reactive/performance/webflux/ProductService.java

@@ -0,0 +1,39 @@
+package com.baeldung.spring.reactive.performance.webflux;
+
+import com.baeldung.spring.reactive.performance.KafkaTemplate;
+import com.baeldung.spring.reactive.performance.ProductAddedToCartEvent;
+import com.baeldung.spring.reactive.performance.model.Price;
+import com.baeldung.spring.reactive.performance.model.Product;
+
+import reactor.core.publisher.Mono;
+
+class ProductService {
+    private final String PRODUCT_ADDED_TO_CART_TOPIC = "product-added-to-cart";
+
+    private final ProductRepository repository;
+    private final DiscountService discountService;
+    private final KafkaTemplate<String, ProductAddedToCartEvent> kafkaTemplate;
+
+    public ProductService(ProductRepository repository, DiscountService discountService) {
+        this.repository = repository;
+        this.discountService = discountService;
+        this.kafkaTemplate = new KafkaTemplate<>();
+    }
+
+    public void addProductToCart(String productId, String cartId) {
+        repository.findById(productId)
+          .switchIfEmpty(Mono.error(() -> new IllegalArgumentException("not found!")))
+          .flatMap(this::computePrice)
+          .map(price -> new ProductAddedToCartEvent(productId, price.value(), price.currency(), cartId))
+          .subscribe(event -> kafkaTemplate.send(PRODUCT_ADDED_TO_CART_TOPIC, cartId, event));
+    }
+
+    private Mono<Price> computePrice(Product product) {
+        if (product.category().isEligibleForDiscount()) {
+            return discountService.discountForProduct(product.id())
+              .map(product.basePrice()::applyDiscount);
+        }
+        return Mono.just(product.basePrice());
+    }
+
+}

spring-reactive-modules/spring-reactive-performance/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

spring-reactive-modules/spring-reactive-performance/src/test/java/com/baeldung/spring/reactive/performance/ApplicationUnitTest.java

@@ -0,0 +1,12 @@
+package com.baeldung.spring.reactive.performance;
+
+import org.junit.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+public class ApplicationUnitTest {
+
+    @Test
+    public void whenSpringContextIsBootstrapped_thenNoExceptions() {
+    }
+}