reactive-bank

This is a proposal of a bank API written using reactive programming and concurrent operations in memory. It exposes a web interface to the external world and handles multiple requests concurrently. Bear in mind that this project was not meant to be ran in a distributed environment since it's data is kept locally without persistance after killing the process.

• Used an in-memory data store. (will not work in distributed systems)
• Chose atomic data models with append-only structures to avoid dealing with ACID transactions.
• Wrote in Java 8 using Streams and immutable objects for composability and thread safety.
• Chose to use async request handling with Javalin and ComputableFuture to allow more web concurrency.
• Designed based on onion/hexagonal architecture. (core domain and infra classes are separeted)
• Followed SOLID principles such as dependency injection and inversion.
• Handled debit account operations with a single Java synchronized for locking to avoid deadlocks.
• Used TDD with JUnit and Mockito for unit and integration tests.

API

Method	Resource	Description
POST	/accounts	Creates an account
GET	/accounts/:id/balance	Retrieves the account balance
POST	/transfers	Transfer money between accounts
POST	/load	Load money into the account
POST	/unload	Unload money from the account

Installing

$ ./gradlew build

Running API

$ ./gradlew run

Default port 8080

Testing

$ ./gradlew test