Feed With Cursor Navigation

We have a feed of 10000 string elements saved in an ordered set in Redis.

Implement a service, allowing to get a part of the feed and to navigate it using cursors. Service responses should also include flags to determine if the previous and/or the next part exists.

Please, use embedded Redis and generate test data on the start of an application.

Do NOT use Spring pagination mechanism. We’re interested in you implementing it from scratch.

Good luck!

Request examples

Feed beginning

GET /feed?limit=3

{
    "items": [
        "first",
        "second",
        "third"
    ],
    "navigation": {
        "prev": "-1",
        "next": "3",
        "hasPrev": false,
        "hasNext": true,
    }
}

Second feed part

Passing .navigation.next as a next GET-parameter to scroll forward. Similarly, use prev to scroll backwards.

GET /feed?limit=3&next=3

{
    "items": [
        "fourth",
        "fifth",
        "sixth"
    ],
    "navigation": {
        "prev": "2",
        "next": "6",
        "hasPrev": true,
        "hasNext": true,
    }
}

Feed end

GET /feed?limit=3&next=9999

{
    "items": [
        "last"
    ],
    "navigation": {
        "prev": "9998",
        "next": "-1",
        "hasPrev": true,
        "hasNext": false
    }
}