ddd-java

Preface

It is DDD sample implementation from Spring Boot.
It is not a framework, This is a simple example of the implementation based on Evans's DDD.

Concept of Layering

It is three levels of famous models, but considers the infrastructure layer as cross-sectional interpretation.

Layer
UI	Receive use case request
Application	Use case processing (including the outside resource access)
Domain	Pure domain logic (not depend on the outside resource)
Infrastructure	DI container and ORM, various libraries

Usually perform public handling of UI layer using Thymeleaf, but this sample assume use of different types of clients and perform only API offer in RESTfulAPI.

Use policy of Spring Boot

Spring Boot is available for various usage, but uses it in the following policy with this sample.

• Use standard definitions as much as possible, such as DB settings.
• The configuration file uses yml. do not use xml files for Bean definition.
• The exception handling defines it in a endpoint (RestErrorAdvice).

Use policy of Java coding

• Java 21 over
• Use Lombok positively and remove diffuseness.
• The name as possible briefly.
• Do not abuse the interface.
• DTO becoming a part of the domain defines it in an internal class.

Resource

Refer to the following for the package / resource constitution.

main
  java
    sample
      context                         … Infrastructure Layer
      controller                      … UI Layer
      model                           … Domain Layer
      usecase                         … Application Layer
      util                            … Utilities
      - Application.java              … Bootstrap
  resources
    - application.yml                 … Spring Boot Configuration
    - messages-validation.properties  … Validation Message Resources
    - messages.properties             … Label Message Resources

Use Case

Consider the following as a sample use case.

• A customer with an account balance requests withdrawal. (Event T, Delivery T + 3)
• The system closes the withdrawal request. (Allows cancellation of request until closing)
• The system sets the business day to the forward day.
• The system reflects the cash flow on delivery date to the account balance.

Getting Started

This sample uses Gradle, you can check the operation without trouble with IDE and a console.

Server Start (VSCode DevContainer)

It is necessary to do the following step.

• Check Instablled Docker.
• Check Instablled VSCode with DevContainer Extension.

Do the preparations for this sample in the next step.

1. You move to the cloned ddd-java directory.
2. Run command code ..
3. Choose Open Container

Do the server start in the next step.

1. Open VSCode "Run And Debug".
2. Choose Run ddd-java.
3. If console show "Started Application", start is completed in port 8080.
4. Run command curl http://localhost:8080/actuator/health

Server Start (Console)

Run application from a console of Windows / Mac in Gradle.

It is necessary to do the following step.

• Check Instablled JDK 21+.

Do the server start in the next step.

1. You move to the cloned ddd-java directory.
2. Run command ./gradlew bootRun --args='--spring.profiles.active=dev'.
3. If console show "Started Application", start is completed in port 8080
4. Run command curl http://localhost:8080/actuator/health

Check Use Case

After launching the server on port 8080, you can test execution of RESTful API by accessing the following URL from console.

Customer Use Case

• curl -X POST -H "Content-Type: application/json" -d '{"accountId" : "sample" , "currency" : "JPY", "absAmount": 1000}' http://localhost:8080/asset/cio/withdraw
  • Request for withdrawal.
• curl 'http://localhost:8080/asset/cio/unprocessedOut'
  • Search for outstanding withdrawal requests

Internal Use Case

• curl 'http://localhost:8080/admin/asset/cio?updFromDay=yyyy-MM-dd&updToDay=yyyy-MM-dd'
  • Search for deposit and withdrawal requests.
  • Please set real date for upd*Day

Batch Use Case

• curl -X POST http://localhost:8080/system/job/daily/closingCashOut
  • Close the withdrawal request.
• curl -X POST http://localhost:8080/system/job/daily/processDay
  • Set the business day to the next day.
• curl -X POST http://localhost:8080/system/job/daily/realizeCashflow
  • Realize cash flow. (Reflected to the balance on the delivery date)

Please execute according to the business day appropriately

License

The license of this sample includes a code and is all MIT License. Use it as a base implementation at the time of the project start using Spring Boot.