First, some facts:
There is key-value storage: Redis.
Java has interface java.util.Map
We like Redis a lot, but using it through a separate client library in Java doesn't really appeal to us. It works, it's convenient, but it's not fun. Again, Java has a basic interface for implementing hash tables - Map. And Redis has a hash data structure.
We would like to work with hashes in Redis through this base interface. That is - I have some object that implements the Map interface, I just pull its get/put/etc. methods, and the data is actually stored in Redis, not in my Java application. Then I could pass that object anywhere the Map interface is expected and everything would just work.
All sorts of other thoughts:
We have a lot of data and it just won't fit on a single Redis machine. It would be nice if the implementation itself could split the data across a cluster of Redis's, completely hiding details about the number of Redis instances and whatnot.
Support for adding/removing Redis servers on the fly is very good. The key word is "on the fly".
Redundancy of data storage in this cluster of redis is an interesting thought. Well, it's so that one redis goes down and its data doesn't go anywhere.
In Java Collections Framework there are other interfaces besides Map - List, Set, SortedSet, Queue, Deque, SortedMap. Here we go.
Details:
It will be quite enough to make only Map[String, Integer] support. You don't need a universal solution for any data types. For List, Set, etc. it will be enough to make List[Integer] or List[String]
You can use any redis-solutions: standalone redis, sentinel or redis-cluster.
You don't need to write your own library to work with Redis, you can use a ready-made one (for example, jedis).
You should write in Java (version 21 and above) or Kotlin.
The assignment must have a working main() method, to demonstrate how it works
In general - do whatever you want, as long as it works.
If you have any questions, feel free to write to join-ecom@lightspeedhq.com.
The completed task should be placed on GitHub
