Statistics API

The main use case for this API is to calculate realtime statistic from the last 60 seconds. There are two APIs, one of them is called every time a transaction is made. It is also the sole input of this rest API. The other one returns the statistic based of the transactions of the last 60 seconds.

API Endpoints

1. POST /transactions

Every time a new transaction happened, this endpoint is called.

Request

POST /transactions HTTP/1.1
Host: localhost:8080
Content-Type: application/json
{
  "amount": 9.99, 
  "timestamp": 1529750938000
}

Response

Returns empty body with either 201 or 204.

• 201 - in case of success
• 204 - if transaction is older than 60 seconds

HTTP/1.1 201 Created
Content-Type: application/json

2. GET /statistics

It returns the statistic of transactions happened in the last 60 seconds.

Request

GET /statistics HTTP/1.1
Host: localhost:8080

Response

HTTP/1.1 200
Content-Type: application/json;charset=UTF-8
{
    "sum": 1179.89,
    "avg": 168.5557142857143,
    "max": 999.5,
    "min": 0.99,
    "count": 7
}

Usage

In order to build this application, run the following gradle command:

gradlew build

To run this applicatin, use the following gradle command:

gradlew bootRun

License

MIT