├── README.md
├── product-command-service
    ├── pom.xml
    └── src
    │   ├── main
    │       ├── java
    │       │   └── com
    │       │   │   └── javatechie
    │       │   │       ├── ProductCommandServiceApplication.java
    │       │   │       ├── controller
    │       │   │           └── ProductCommandController.java
    │       │   │       ├── dto
    │       │   │           └── ProductEvent.java
    │       │   │       ├── entity
    │       │   │           └── Product.java
    │       │   │       ├── repository
    │       │   │           └── ProductRepository.java
    │       │   │       └── service
    │       │   │           └── ProductCommandService.java
    │       └── resources
    │       │   ├── application.properties
    │       │   └── application.yml
    │   └── test
    │       └── java
    │           └── com
    │               └── javatechie
    │                   └── ProductCommandServiceApplicationTests.java
└── product-query-service
    ├── pom.xml
    └── src
        ├── main
            ├── java
            │   └── com
            │   │   └── javatechie
            │   │       ├── ProductQueryServiceApplication.java
            │   │       ├── controller
            │   │           └── ProductQueryController.java
            │   │       ├── dto
            │   │           └── ProductEvent.java
            │   │       ├── entity
            │   │           └── Product.java
            │   │       ├── repository
            │   │           └── ProductRepository.java
            │   │       └── service
            │   │           └── ProductQueryService.java
            └── resources
            │   ├── application.properties
            │   └── application.yml
        └── test
            └── java
                └── com
                    └── javatechie
                        └── ProductQueryServiceApplicationTests.java


/README.md:
--------------------------------------------------------------------------------
 1 | # cqrs-design-pattern
 2 | 
 3 | ### CreateProduct Event
 4 | 
 5 | ```
 6 | curl --location 'http://localhost:9191/products' \
 7 | --header 'Content-Type: application/json' \
 8 | --data '{
 9 |     "type": "CreateProduct",
10 |     "product": {
11 |         "name": "Books",
12 |         "description": "KK publication",
13 |         "price": 999
14 |     }
15 | }'
16 | ```
17 | ### UpdateProduct Event
18 | 
19 | ```
20 | curl --location --request PUT 'http://localhost:9191/products/1' \
21 | --header 'Content-Type: application/json' \
22 | --data '{
23 |     "type": "UpdateProduct",
24 |     "product": {
25 |         "id": 1,
26 |         "name": "Watch",
27 |         "description": "Samsung latest model",
28 |         "price": 58000.0
29 |     }
30 | }'
31 | ```
32 | 


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/product-command-service/pom.xml:
--------------------------------------------------------------------------------
 1 | <?xml version="1.0" encoding="UTF-8"?>
 2 | <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 3 | 	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
 4 | 	<modelVersion>4.0.0</modelVersion>
 5 | 	<parent>
 6 | 		<groupId>org.springframework.boot</groupId>
 7 | 		<artifactId>spring-boot-starter-parent</artifactId>
 8 | 		<version>3.1.2</version>
 9 | 		<relativePath/> <!-- lookup parent from repository -->
10 | 	</parent>
11 | 	<groupId>com.javatechie</groupId>
12 | 	<artifactId>product-command-service</artifactId>
13 | 	<version>0.0.1-SNAPSHOT</version>
14 | 	<name>product-command-service</name>
15 | 	<description>Demo project for Spring Boot</description>
16 | 	<properties>
17 | 		<java.version>17</java.version>
18 | 	</properties>
19 | 	<dependencies>
20 | 		<dependency>
21 | 			<groupId>org.springframework.boot</groupId>
22 | 			<artifactId>spring-boot-starter-data-jpa</artifactId>
23 | 		</dependency>
24 | 		<dependency>
25 | 			<groupId>org.springframework.boot</groupId>
26 | 			<artifactId>spring-boot-starter-web</artifactId>
27 | 		</dependency>
28 | 		<dependency>
29 | 			<groupId>org.springframework.kafka</groupId>
30 | 			<artifactId>spring-kafka</artifactId>
31 | 		</dependency>
32 | 		<dependency>
33 | 			<groupId>com.mysql</groupId>
34 | 			<artifactId>mysql-connector-j</artifactId>
35 | 			<scope>runtime</scope>
36 | 		</dependency>
37 | 		<dependency>
38 | 			<groupId>org.projectlombok</groupId>
39 | 			<artifactId>lombok</artifactId>
40 | 			<optional>true</optional>
41 | 		</dependency>
42 | 		<dependency>
43 | 			<groupId>org.springframework.boot</groupId>
44 | 			<artifactId>spring-boot-starter-test</artifactId>
45 | 			<scope>test</scope>
46 | 		</dependency>
47 | 	</dependencies>
48 | 
49 | 	<build>
50 | 		<plugins>
51 | 			<plugin>
52 | 				<groupId>org.springframework.boot</groupId>
53 | 				<artifactId>spring-boot-maven-plugin</artifactId>
54 | 				<configuration>
55 | 					<excludes>
56 | 						<exclude>
57 | 							<groupId>org.projectlombok</groupId>
58 | 							<artifactId>lombok</artifactId>
59 | 						</exclude>
60 | 					</excludes>
61 | 				</configuration>
62 | 			</plugin>
63 | 		</plugins>
64 | 	</build>
65 | 
66 | </project>
67 | 


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/product-command-service/src/main/java/com/javatechie/ProductCommandServiceApplication.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie;
 2 | 
 3 | import org.springframework.boot.SpringApplication;
 4 | import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 | 
 6 | @SpringBootApplication
 7 | public class ProductCommandServiceApplication {
 8 | 
 9 | 	public static void main(String[] args) {
10 | 		SpringApplication.run(ProductCommandServiceApplication.class, args);
11 | 	}
12 | 
13 | }
14 | 


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/product-command-service/src/main/java/com/javatechie/controller/ProductCommandController.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie.controller;
 2 | 
 3 | import com.javatechie.dto.ProductEvent;
 4 | import com.javatechie.entity.Product;
 5 | import com.javatechie.service.ProductCommandService;
 6 | import org.springframework.beans.factory.annotation.Autowired;
 7 | import org.springframework.web.bind.annotation.*;
 8 | 
 9 | @RestController
10 | @RequestMapping("/products")
11 | public class ProductCommandController {
12 | 
13 |     @Autowired
14 |     private ProductCommandService commandService;
15 | 
16 |     @PostMapping
17 |     public Product createProduct(@RequestBody ProductEvent productEvent) {
18 |         return commandService.createProduct(productEvent);
19 |     }
20 | 
21 |     @PutMapping("/{id}")
22 |     public Product updateProduct(@PathVariable long id, @RequestBody ProductEvent productEvent) {
23 |         return commandService.updateProduct(id, productEvent);
24 |     }
25 | }
26 | 


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/product-command-service/src/main/java/com/javatechie/dto/ProductEvent.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie.dto;
 2 | 
 3 | import com.javatechie.entity.Product;
 4 | import lombok.AllArgsConstructor;
 5 | import lombok.Data;
 6 | import lombok.NoArgsConstructor;
 7 | 
 8 | @Data
 9 | @AllArgsConstructor
10 | @NoArgsConstructor
11 | public class ProductEvent {
12 | 
13 |     private String eventType;
14 |     private Product product;
15 | }
16 | 


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/product-command-service/src/main/java/com/javatechie/entity/Product.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie.entity;
 2 | 
 3 | import jakarta.persistence.Entity;
 4 | import jakarta.persistence.GeneratedValue;
 5 | import jakarta.persistence.Id;
 6 | import jakarta.persistence.Table;
 7 | import lombok.AllArgsConstructor;
 8 | import lombok.Data;
 9 | import lombok.NoArgsConstructor;
10 | 
11 | @Entity
12 | @Table(name = "PRODUCT_COMMAND")
13 | @Data
14 | @AllArgsConstructor
15 | @NoArgsConstructor
16 | public class Product {
17 |     @Id
18 |     @GeneratedValue
19 |     private Long id;
20 |     private String name;
21 |     private String description;
22 |     private double price;
23 | }
24 | 


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/product-command-service/src/main/java/com/javatechie/repository/ProductRepository.java:
--------------------------------------------------------------------------------
1 | package com.javatechie.repository;
2 | 
3 | import com.javatechie.entity.Product;
4 | import org.springframework.data.jpa.repository.JpaRepository;
5 | 
6 | public interface ProductRepository extends JpaRepository<Product,Long> {
7 | }
8 | 


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/product-command-service/src/main/java/com/javatechie/service/ProductCommandService.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie.service;
 2 | 
 3 | import com.javatechie.dto.ProductEvent;
 4 | import com.javatechie.entity.Product;
 5 | import com.javatechie.repository.ProductRepository;
 6 | import org.springframework.beans.factory.annotation.Autowired;
 7 | import org.springframework.kafka.core.KafkaTemplate;
 8 | import org.springframework.stereotype.Service;
 9 | 
10 | @Service
11 | public class ProductCommandService {
12 | 
13 |     @Autowired
14 |     private ProductRepository repository;
15 | 
16 |     @Autowired
17 |     private KafkaTemplate<String,Object> kafkaTemplate;
18 | 
19 |     public Product createProduct(ProductEvent productEvent){
20 |         Product productDO = repository.save(productEvent.getProduct());
21 |         ProductEvent event=new ProductEvent("CreateProduct", productDO);
22 |         kafkaTemplate.send("product-event-topic", event);
23 |         return productDO;
24 |     }
25 | 
26 |     public Product updateProduct(long id,ProductEvent productEvent){
27 |         Product existingProduct = repository.findById(id).get();
28 |         Product newProduct=productEvent.getProduct();
29 |         existingProduct.setName(newProduct.getName());
30 |         existingProduct.setPrice(newProduct.getPrice());
31 |         existingProduct.setDescription(newProduct.getDescription());
32 |         Product productDO = repository.save(existingProduct);
33 |         ProductEvent event=new ProductEvent("UpdateProduct", productDO);
34 |         kafkaTemplate.send("product-event-topic", event);
35 |         return productDO;
36 |     }
37 | 
38 | }
39 | 


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/product-command-service/src/main/resources/application.properties:
--------------------------------------------------------------------------------
1 | spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
2 | spring.datasource.url = jdbc:mysql://localhost:3306/javatechie
3 | spring.datasource.username = root
4 | spring.datasource.password = Password
5 | spring.jpa.show-sql = true
6 | spring.jpa.hibernate.ddl-auto = update
7 | spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQLDialect
8 | server.port=9191
9 | 


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/product-command-service/src/main/resources/application.yml:
--------------------------------------------------------------------------------
1 | spring:
2 |   kafka:
3 |     producer:
4 |       bootstrap-servers: localhost:9092
5 |       key-serializer: org.apache.kafka.common.serialization.StringSerializer
6 |       value-serializer:  org.springframework.kafka.support.serializer.JsonSerializer


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/product-command-service/src/test/java/com/javatechie/ProductCommandServiceApplicationTests.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie;
 2 | 
 3 | import org.junit.jupiter.api.Test;
 4 | import org.springframework.boot.test.context.SpringBootTest;
 5 | 
 6 | @SpringBootTest
 7 | class ProductCommandServiceApplicationTests {
 8 | 
 9 | 	@Test
10 | 	void contextLoads() {
11 | 	}
12 | 
13 | }
14 | 


--------------------------------------------------------------------------------
/product-query-service/pom.xml:
--------------------------------------------------------------------------------
 1 | <?xml version="1.0" encoding="UTF-8"?>
 2 | <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 3 | 	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
 4 | 	<modelVersion>4.0.0</modelVersion>
 5 | 	<parent>
 6 | 		<groupId>org.springframework.boot</groupId>
 7 | 		<artifactId>spring-boot-starter-parent</artifactId>
 8 | 		<version>3.1.2</version>
 9 | 		<relativePath/> <!-- lookup parent from repository -->
10 | 	</parent>
11 | 	<groupId>com.javatechie</groupId>
12 | 	<artifactId>product-query-service</artifactId>
13 | 	<version>0.0.1-SNAPSHOT</version>
14 | 	<name>product-query-service</name>
15 | 	<description>Demo project for Spring Boot</description>
16 | 	<properties>
17 | 		<java.version>17</java.version>
18 | 	</properties>
19 | 	<dependencies>
20 | 		<dependency>
21 | 			<groupId>org.springframework.boot</groupId>
22 | 			<artifactId>spring-boot-starter-data-jpa</artifactId>
23 | 		</dependency>
24 | 		<dependency>
25 | 			<groupId>org.springframework.boot</groupId>
26 | 			<artifactId>spring-boot-starter-web</artifactId>
27 | 		</dependency>
28 | 		<dependency>
29 | 			<groupId>org.springframework.kafka</groupId>
30 | 			<artifactId>spring-kafka</artifactId>
31 | 		</dependency>
32 | 		<dependency>
33 | 			<groupId>com.mysql</groupId>
34 | 			<artifactId>mysql-connector-j</artifactId>
35 | 			<scope>runtime</scope>
36 | 		</dependency>
37 | 		<dependency>
38 | 			<groupId>org.projectlombok</groupId>
39 | 			<artifactId>lombok</artifactId>
40 | 			<optional>true</optional>
41 | 		</dependency>
42 | 		<dependency>
43 | 			<groupId>org.springframework.boot</groupId>
44 | 			<artifactId>spring-boot-starter-test</artifactId>
45 | 			<scope>test</scope>
46 | 		</dependency>
47 | 	</dependencies>
48 | 
49 | 	<build>
50 | 		<plugins>
51 | 			<plugin>
52 | 				<groupId>org.springframework.boot</groupId>
53 | 				<artifactId>spring-boot-maven-plugin</artifactId>
54 | 				<configuration>
55 | 					<excludes>
56 | 						<exclude>
57 | 							<groupId>org.projectlombok</groupId>
58 | 							<artifactId>lombok</artifactId>
59 | 						</exclude>
60 | 					</excludes>
61 | 				</configuration>
62 | 			</plugin>
63 | 		</plugins>
64 | 	</build>
65 | 
66 | </project>
67 | 


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/product-query-service/src/main/java/com/javatechie/ProductQueryServiceApplication.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie;
 2 | 
 3 | import org.springframework.boot.SpringApplication;
 4 | import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 | 
 6 | @SpringBootApplication
 7 | public class ProductQueryServiceApplication {
 8 | 
 9 | 	public static void main(String[] args) {
10 | 		SpringApplication.run(ProductQueryServiceApplication.class, args);
11 | 	}
12 | 
13 | }
14 | 


--------------------------------------------------------------------------------
/product-query-service/src/main/java/com/javatechie/controller/ProductQueryController.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie.controller;
 2 | 
 3 | import com.javatechie.dto.ProductEvent;
 4 | import com.javatechie.entity.Product;
 5 | import com.javatechie.service.ProductQueryService;
 6 | import org.springframework.beans.factory.annotation.Autowired;
 7 | import org.springframework.web.bind.annotation.GetMapping;
 8 | import org.springframework.web.bind.annotation.RequestMapping;
 9 | import org.springframework.web.bind.annotation.RestController;
10 | 
11 | import java.util.List;
12 | 
13 | @RequestMapping("/products")
14 | @RestController
15 | public class ProductQueryController {
16 | 
17 |     @Autowired
18 |     private ProductQueryService queryService;
19 | 
20 |     @GetMapping
21 |     public List<Product> fetchAllProducts(){
22 |         return queryService.getProducts();
23 |     }
24 | 
25 | 
26 | }
27 | 


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/product-query-service/src/main/java/com/javatechie/dto/ProductEvent.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie.dto;
 2 | 
 3 | import com.javatechie.entity.Product;
 4 | import lombok.AllArgsConstructor;
 5 | import lombok.Data;
 6 | import lombok.NoArgsConstructor;
 7 | 
 8 | @Data
 9 | @AllArgsConstructor
10 | @NoArgsConstructor
11 | public class ProductEvent {
12 | 
13 |     private String eventType;
14 |     private Product product;
15 | }
16 | 


--------------------------------------------------------------------------------
/product-query-service/src/main/java/com/javatechie/entity/Product.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie.entity;
 2 | 
 3 | import jakarta.persistence.Entity;
 4 | import jakarta.persistence.GeneratedValue;
 5 | import jakarta.persistence.Id;
 6 | import jakarta.persistence.Table;
 7 | import lombok.AllArgsConstructor;
 8 | import lombok.Data;
 9 | import lombok.NoArgsConstructor;
10 | 
11 | @Entity
12 | @Table(name = "PRODUCT_QUERY")
13 | @Data
14 | @AllArgsConstructor
15 | @NoArgsConstructor
16 | public class Product {
17 |     @Id
18 |     @GeneratedValue
19 |     private Long id;
20 |     private String name;
21 |     private String description;
22 |     private double price;
23 | }
24 | 


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/product-query-service/src/main/java/com/javatechie/repository/ProductRepository.java:
--------------------------------------------------------------------------------
1 | package com.javatechie.repository;
2 | 
3 | import com.javatechie.entity.Product;
4 | import org.springframework.data.jpa.repository.JpaRepository;
5 | 
6 | public interface ProductRepository extends JpaRepository<Product,Long> {
7 | }
8 | 


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/product-query-service/src/main/java/com/javatechie/service/ProductQueryService.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie.service;
 2 | 
 3 | import com.javatechie.dto.ProductEvent;
 4 | import com.javatechie.entity.Product;
 5 | import com.javatechie.repository.ProductRepository;
 6 | import org.springframework.beans.factory.annotation.Autowired;
 7 | import org.springframework.kafka.annotation.KafkaListener;
 8 | import org.springframework.stereotype.Service;
 9 | 
10 | import java.util.List;
11 | import java.util.Optional;
12 | 
13 | @Service
14 | public class ProductQueryService {
15 | 
16 |     @Autowired
17 |     private ProductRepository repository;
18 | 
19 |     public List<Product> getProducts() {
20 |         return repository.findAll();
21 |     }
22 | 
23 |     @KafkaListener(topics = "product-event-topic",groupId = "product-event-group")
24 |     public void processProductEvents(ProductEvent productEvent) {
25 |         Product product = productEvent.getProduct();
26 |         if (productEvent.getEventType().equals("CreateProduct")) {
27 |             repository.save(product);
28 |         }
29 |         if (productEvent.getEventType().equals("UpdateProduct")) {
30 |             Product existingProduct = repository.findById(product.getId()).get();
31 |             existingProduct.setName(product.getName());
32 |             existingProduct.setPrice(product.getPrice());
33 |             existingProduct.setDescription(product.getDescription());
34 |             repository.save(existingProduct);
35 |         }
36 |     }
37 | }
38 | 


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/product-query-service/src/main/resources/application.properties:
--------------------------------------------------------------------------------
 1 | spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
 2 | spring.datasource.url = jdbc:mysql://localhost:3306/javatechie
 3 | spring.datasource.username = root
 4 | spring.datasource.password = Password
 5 | spring.jpa.show-sql = true
 6 | spring.jpa.hibernate.ddl-auto = update
 7 | spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQLDialect
 8 | server.port=9292
 9 | 
10 | 


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/product-query-service/src/main/resources/application.yml:
--------------------------------------------------------------------------------
 1 | spring:
 2 |   kafka:
 3 |     consumer:
 4 |       bootstrap-servers: localhost:9092
 5 |       key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
 6 |       value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
 7 |       properties:
 8 |         spring:
 9 |           json:
10 |             trusted:
11 |               packages: com.javatechie.dto


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/product-query-service/src/test/java/com/javatechie/ProductQueryServiceApplicationTests.java:
--------------------------------------------------------------------------------
 1 | package com.javatechie;
 2 | 
 3 | import org.junit.jupiter.api.Test;
 4 | import org.springframework.boot.test.context.SpringBootTest;
 5 | 
 6 | @SpringBootTest
 7 | class ProductQueryServiceApplicationTests {
 8 | 
 9 | 	@Test
10 | 	void contextLoads() {
11 | 	}
12 | 
13 | }
14 | 


--------------------------------------------------------------------------------