ashish1189 / transaction-statistics-service

Concurrent transactions statistics service

Transaction Statistics Service

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RESTful API to to calculate realtime statistics for the last 60 seconds of transactions.

URL

• /transactions

Method

• POST | DELETE

  ####Create Transactions POST /transactions endpoint is called to create a new transaction. It executes in constant time and memory (O(1)).

  Request Body

  {
      "amount": "30",
      "timestamp": "2021-04-04T11:37:35.312Z"
  }

  Where

    * amount -  transaction amount; a string of arbitrary length that is parsable as a BigDecimal
    * timestamp - transaction time in the ISO 8601 format YYYY-MM-DDThh:mm:ss.sssZ in the UTC timezone (this is not the current timestamp)
  

  Response

  Empty body with one of the following:
      201 – in case of success
      204 – if the transaction is older than 60 seconds
      400 – if the JSON is invalid
      422 – if any of the fields are not parsable or the transaction date is in the future
  

  ####Delete Transactions DELETE /transactions This endpoint causes all existing transactions to be deleted. The endpoint should accept an empty request body and return a 204 status code.

URL

• /statistics

Method

• GET

  ####Get realtime statistics GET /statistics endpoint returns the statistics based on the transactions that happened in the last 60 seconds. It MUST execute in constant time and memory (O(1)).

  Response

  {
      "sum": "60.00",
      "avg": "20.00",
      "max": "30.00",
      "min": "10.00",
      "count": 3
  }

  Where

    ● sum – a BigDecimal specifying the total sum of transaction value in the last 60 seconds
  
    ● avg – a BigDecimal specifying the average amount of transaction value in the last 60 seconds
  
    ● max – a BigDecimal specifying single highest transaction value in the last 60 seconds
    
    ● min – a BigDecimal specifying single lowest transaction value in the last 60 seconds
    
    ● count – a long specifying the total number of transactions that happened in the last 60 seconds
  
    * Note - All BigDecimal values always contain exactly two decimal places and use `HALF_ROUND_UP` 
             rounding. eg: 10.345 is returned as 10.35, 10.8 is returned as 10.80