tx-money-service

An RESTful API for money transfers between accounts. Provides 6 accounts, 5 example money transactions and an interface to fetch account balance, transaction details and create new transactions (sending money between those six accounts).

An executable jar with project can be downloaded from link.

Getting Started

Prerequisites

Java 11

Run prebuild jar file

Executing java -jar tx-money-service-0.1.0.jar will start application on http://localhost:3137

Jar file with application is located in ./jars

Build and run from sources

In the project root directory run:

• ./gradlew clean build run to build and run project
• ./gradlew clean jar to build executable jar archive and then java -jar ./build/libs/tx-money-service-0.1.0.jar

Project structure

├── jars                                                        # Prebuilt executable jars 
│   └── tx-money-service-0.1.0.jar
└── src
    ├── main
    │   ├── java
    │   │   └── com
    │   │       └── bank
    │   │           ├── app
    │   │           │   ├── ApplicationContext.java             
    │   │           │   └── JavalinApplication.java             # Javalin configuration  
    │   │           ├── db
    │   │           │   └── Functions.java                      # Embedded database stored procedures
    │   │           ├── exception
    │   │           │   ├── DatabaseException.java
    │   │           │   ├── EntityNotFoundException.java
    │   │           │   └── NotEnoughMoneyException.java
    │   │           ├── Main.java                               # Application entry point
    │   │           ├── pojo
    │   │           │   ├── AccountDto.java
    │   │           │   ├── ErrorResponse.java
    │   │           │   ├── PostTransactionDto.java
    │   │           │   └── TransactionDto.java
    │   │           ├── repository
    │   │           │   └── Repository.java
    │   │           ├── resource
    │   │           │   ├── AccountResource.java
    │   │           │   └── TransactionResource.java
    │   │           └── service
    │   │               ├── AccountService.java
    │   │               └── TransactionService.java
    │   └── resources
    │       └── initdb.sql                                      # Embedded database initialization script                               
    └── test
        └── java
            └── com
                └── bank
                    ├── ApplicationTest.java                    # Integration test
                    ├── db
                    │   └── FunctionsTest.java
                    ├── repository
                    │   └── RepositoryTest.java
                    └── service
                        ├── AccountServiceTest.java
                        └── TransactionServiceTest.java

API Overview

1. Introduction
2. Get account balance
3. Get transaction details
4. Create new transaction

Introduction

Application comes with six accounts:

accountId	balance (coins)
1	1_000_000.00
2	500_000.00
3	500_000.00
4	474_999.75
5	25_000.25
6	0.00

and five example transactions:

transactionId	creation_time	amount	recipient	sender
1	2019-08-13 00:00	2500000.00	1	0
2	2019-08-13 01:01	500000.00	2	1
3	2019-08-13 02:02	500000.00	3	1
4	2019-08-13 03:03	500000.00	4	1
5	2019-08-13 04:04	25000.25	5	4

where:

• sender - accountId that sends money
• recipient - accountId that receives money

The API allows you to create new transactions thereby sending money between those six accounts.

Get account balance

curl -X GET http://localhost:3137/account/{accountId}

For example, curl -X GET http://localhost:3137/account/1 will return

{
  "accountId": 1,
  "balance": 1000000.00
}

Get transaction details

curl -X GET http://localhost:3137/transaction/{transactionId}

For example, curl -X GET http://localhost:3137/transaction/1 will return

{
  "transactionId": 1,
  "creationTime": "2019-08-13T00:00:00",
  "amount": 2500000.00,
  "sender": 0,
  "recipient": 1
}

where:

• sender - accountId that sends money
• recipient - accountId that receives money

Create new transaction

curl -d '{ "amount":{amount}, "recipient":{accountId}, "sender":{accountId} }' -H "Content-Type: application/json" -X POST http://localhost:3137/transaction

returns

{
  "transactionId": "{id of created transaction}"
}

For example:

curl -d '{"amount":2000, "recipient":6, "sender":5}' -H "Content-Type: application/json" -X POST http://localhost:3137/transaction

will return

{
  "transactionId": 6
}

Then, we can check that transaction is created:

curl -X GET http://localhost:3137/transaction/6

{
  "transactionId": 6,
  "creationTime": "2019-08-27T00:00:00",
  "amount": 2000,
  "sender": 5,
  "recipient": 6
}

and sender and recipient balances are updated:

curl -X GET http://localhost:3137/account/5 - sender

{
  "accountId": 5,
  "balance": 23000.25
}

curl -X GET http://localhost:3137/account/6 - recipient

{
  "accountId": 6,
  "balance": 2000.00
}