[FIXED] How can I put a delayed method execution to the Map?

Issue

How can I put a delay Spring repository method execution to Map? Is it possible to do something like this?

final Map<T, Function<T, R>> maps = new LinkedHashMap<>();
maps.put(product, productRepository::save);
maps.put(client, clientRepository::save);

The productRepository and the clientRepository there're Spring repositories.

Solution

You can do it, for instance like that:

public class Sample {

    public static void main(String[] args) {
        Demo<Integer, String> demo = new Demo<>();
        demo.put(1, String::valueOf);

        System.out.println(demo.get(1).apply(15).getClass());
    }

    static class Demo<T, R> {

        private final Map<T, Function<T, R>> maps = new ConcurrentHashMap<>();

        void put(T key, Function<T, R> mapper) {
            maps.put(key, mapper);
        }

        Function<T, R> get(T key) {
            return maps.get(key);
        }
    }
}

Output: class java.lang.String

Answered By - Dmitrii B
Answer Checked By - Pedro (JavaFixing Volunteer)