CQRS and event sourcing app

CQRS and event sourcing using plain embedded into jdk com.sun.net.httpserver with dynamic groovy spock tests

TL;DR

this is an example of event sourced system I'm using for teaching my students, so please, don't even try use it in production: Also read: Why Developers Should Not Write Programs That Call 'sun' Packages

Status: in progress...

RoadMap:

• Setup Gradle / Groovy repository with Spring IoC dependency injection and Spock test framework
• Implement REST API with plain java embedded http server
• Implement basic REST API info and shutdown endpoints
• Implement and cover with tests User Account aggregate functionality
• Implement and cover with tests User Account aggregate repository functionality
• Implement user-account REST API endpoints
• Implement Friend Request aggregate functionality
• Implement Friend Request aggregate repository functionality
• Implement friend-request REST API endpoints
• Implement messenger aggregate functionality
• Implement messenger aggregate repository functionality
• Implement messenger REST API endpoints
• Implement async PubSub / Queue functionality to decouple direct REST API calls from aggregate repository
• Introduce read (query) side to avoid non efficient event sourcing repository querying
• Split current REST API into CQRS for eventual consistency and projections efficiency
• Implement CLI interface which is going to be interact with REST API by using CQRS
• Prepare future RoadMap for EventStore persistence introduction:
  • MapDB
  • JDBC
  • JPA
  • Spring Data
  • NoSQL
  • etc...
• Prepare future RoadMap for PubSub introduction:
  • plain pub-sub patter implementation
  • simple im-memory pub-sub solution from Google or Android library
  • Using spring application events
  • Kafka

NOTE: For better developer experience during testing, use idea cURL integration tests from rest-client* files. Read more: https://www.jetbrains.com/help/idea/http-client-in-product-code-editor.html

why?

just see how everything is clear in next analitics:

events:
- OrderCreated(id=123)
- ItemAdded(product=Bose Headphones, price=400)
- FollowSimilarItemsLink(product=Sony Headphones)
- AccessReviews()
- VoteReviewHelpful(answer=5/5)
- ItemAdded(product=Sony Headphones, price=450)
- ItemRemoved(product=Bose Headphones, price=400)
- OrderConfirmed()
- OrderShipped()

resources:

• @Log4l2