Question 121638 in Redis Question posted in
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How to map HSCAN response to Map<key, value> using Vert.x Redis

I am using io.quarkus.redis.client.RedisClient which inside use Vert.x for a Redis Client in Java. When I use HSCAN method it return a list of key and values in differents rows like this:

enter image description here

The keys are 0,2,4… and the values are the JSONs. Is there a way to obtain a Map<key,value> instead of a list with a key and values mix in a elegant/clean way?

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2

Answers


  1. 0

    You will need to iterate over the Response in order to get the map.

    Here is an example for Map<String, String> with for loop:

    Map<String, String> map = new HashMap<>();
for (String key : results.getKeys()) {
    map.put(key, results.get(key).toString());
}

    Here is the same example but using java lambdas:

    Map<String, String> map = result.getKeys().stream()
    .collect(Collectors.toMap(key -> key, key -> result.get(key).toString()));

    For your case with json you can just change the transformation function from .toString() to something that suits your need.

    Edit 1:

    As HSCAN returns array as defined:

    return a two elements multi-bulk reply, where the first element is a
    string representing an unsigned 64 bit number (the cursor), and the
    second element is a multi-bulk with an array of elements.

    There is not a simple solution to create a map but this is what I recommend:

    Iterator<Response> iterator = response.get(1).stream().iterator();
Map<String, String> map = new HashMap<>();
    while (iterator.hasNext()) {
        map.put(iterator.next().toString(), iterator.next().toString());
    }
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  2. 0

    You can do it with a simple for

            Map<String, String> result = new HashMap<>();

        for (int i = 0; i < source.length; i+=2) {
            result.put(source[i], source[i + 1]);
        }

    In Kotlin you can use a more elegant solution but I think this one works

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