CSV parse project

Task

This repository contains solution for the given problem:

On the input you've got 3 files containing:

• data.csv - product representation with price, currency, quantity, matching_id
• currencies.csv - currency code and ratio to PLN, ie. GBP,2.4 can be converted to PLN with procedure 1 PLN * 2.4
• matchings.csv - matching data matching_id, top_priced_count

Now, read all the data. From products with particular matching_id take those with the highest total price (price * quantity), limit data set by top_priced_count and aggregate prices. Result save to top_products.csv with five columns: matching_id,total_price,avg_price,currency,ignored_products_count.

Notes

As I didn't have more details for the implementation itself I have decided that guys giving me task wanted to see my code so I have used pure Java as much as possible.

In real world I would rather implement whole (or biggest part of) logic inside some DB engine.

Next point - parsing of the csv document. I have also implemented my own bicycle and in the real world I would rather use library jackson-dataformat-csv or delegate the task to DB engine.

Implementation decisions

Not sure that I've got the result wanted from me but I've implemented the logic for average value calculation for the product currency.

That said if we have products with different currencies but the same matching id than average will be calculated and written to each row in its own currency.