/money-transfer

Primary LanguageGroovy

Money Transfer Backend

Simple implementation of money transfer API.

  • It uses in memory H2 DB
  • To ensure data consistency pessimistic lock is acquired on the accounts being involved in the money transfer
  • Event sourcing approach is used to store the account balances

Libraries used

  • spark
  • gson
  • sql2o
  • h2

How to run

Directly from gradle:

./gradlew run

or produce fat jar and run it:

./gradlew fatJar && java -jar ./build/libs/money-transfer-fat.jar

API

  • POST /accounts new account
    Body: {"balance": 10.0}
    Response: {"id": 1, "balance": 10.0}
  • GET /accounts/:id account balance
    Response: {"id": 1, "balance": 10.0}
  • GET /accounts/:id/transfers account transfer history
    [{"fromAccount": 1, "toAccount": 2, "amount": 100, "timestamp": "2019-01-27T21:30:36.023"}]
  • POST /transfers new transfer
    Body: {"fromAccount": 1, "toAccount": 2, "amount": 100.0}
    Response: {"fromAccount": 1, "toAccount": 2, "amount": 100, "timestamp": "2019-01-27T21:30:36.023"}

Error responses format:

{
   "exception": "com.example.moneytransfer.exceptions.InsufficientFundsException",
   "message": "Account 1 has insufficient funds to debit 100.00"
}