Code challenge (Aleksei Chaika, statistics service)

About

This is implementation of service for handling transactions and generating statistics about them oin real-time(based on REST API).

Notes

By default statistics is stored for transactions not older than 60 secs (configurable in application.yml) Port could be configured in properties too. Main logic happens inside of StatisticMonitor. Endpoint for getting statistics executes in O(1), as it was required, because statistic getting doe not require any math operations - it just uses statistics that changes in real time. It was achieved by using scheduled transactions removing from collection with recalculating stats (in another thread in ScheduledExecutorService). There were no requirements about logging or old transactions storing, so all deleted from StatisticMonitor transactions will be lost forever.

Start Application

To run application just use gradlew bootRun, I've also added simple integration test that actually helped me a little bit, to run it use gradlew clean test --info

Using application

Use next endpoints:

• submit transaction - POST 127.0.0.1:8000/transactions with {"amount":"2.20","timestamp":"999999999"}
• get statistics - GET 127.0.0.1:8000/statistics Port is configurable